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<front>
<journal-meta>
<journal-id journal-id-type="publisher-id">Front. Med.</journal-id>
<journal-title>Frontiers in Medicine</journal-title>
<abbrev-journal-title abbrev-type="pubmed">Front. Med.</abbrev-journal-title>
<issn pub-type="epub">2296-858X</issn>
<publisher>
<publisher-name>Frontiers Media S.A.</publisher-name>
</publisher>
</journal-meta>
<article-meta>
<article-id pub-id-type="doi">10.3389/fmed.2025.1666703</article-id>
<article-categories>
<subj-group subj-group-type="heading">
<subject>Medicine</subject>
<subj-group>
<subject>Original Research</subject>
</subj-group>
</subj-group>
</article-categories>
<title-group>
<article-title>Dynamic performance and scenario-based screening strategy of six COPD questionnaires: a cross-sectional study with prevalence-driven robustness validation</article-title>
</title-group>
<contrib-group>
<contrib contrib-type="author" equal-contrib="yes">
<name><surname>Wang</surname> <given-names>Qinqin</given-names></name>
<xref ref-type="aff" rid="aff1"><sup>1</sup></xref>
<xref ref-type="aff" rid="aff2"><sup>2</sup></xref>
<xref ref-type="author-notes" rid="fn002"><sup>&#x2020;</sup></xref>
<uri xlink:href="http://loop.frontiersin.org/people/3135304/overview"/>
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<contrib contrib-type="author" equal-contrib="yes">
<name><surname>Liu</surname> <given-names>Lingjun</given-names></name>
<xref ref-type="aff" rid="aff1"><sup>1</sup></xref>
<xref ref-type="aff" rid="aff2"><sup>2</sup></xref>
<xref ref-type="author-notes" rid="fn002"><sup>&#x2020;</sup></xref>
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<contrib contrib-type="author">
<name><surname>Zhang</surname> <given-names>Qiao</given-names></name>
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<contrib contrib-type="author">
<name><surname>Li</surname> <given-names>Hong</given-names></name>
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<xref ref-type="aff" rid="aff2"><sup>2</sup></xref>
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<contrib contrib-type="author" corresp="yes">
<name><surname>Ma</surname> <given-names>Qianli</given-names></name>
<xref ref-type="aff" rid="aff1"><sup>1</sup></xref>
<xref ref-type="aff" rid="aff2"><sup>2</sup></xref>
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<aff id="aff1"><sup>1</sup><institution>Department of Chronic Respiratory Disease Management and Rehabilitation Center, Chongqing Songshan General Hospital</institution>, <addr-line>Chongqing</addr-line>, <country>China</country></aff>
<aff id="aff2"><sup>2</sup><institution>Department of Allergy and Immunology, Chongqing Songshan General Hospital</institution>, <addr-line>Chongqing</addr-line>, <country>China</country></aff>
<aff id="aff3"><sup>3</sup><institution>Department of Respiratory and Critical Care Medicine, Chongqing Songshan General Hospital</institution>, <addr-line>Chongqing</addr-line>, <country>China</country></aff>
<author-notes>
<fn fn-type="edited-by"><p>Edited by: <ext-link ext-link-type="uri" xlink:href="https://loop.frontiersin.org/people/1997588/overview">Roberto Giovanni Carbone</ext-link>, University of Genoa, Italy</p></fn>
<fn fn-type="edited-by"><p>Reviewed by: <ext-link ext-link-type="uri" xlink:href="https://loop.frontiersin.org/people/911543/overview">Dinh Tuan Phan Le</ext-link>, New York City Health and Hospitals Corporation, United States</p>
<p><ext-link ext-link-type="uri" xlink:href="https://loop.frontiersin.org/people/3191405/overview">Faisal Yunus</ext-link>, University of Indonesia, Indonesia</p></fn>
<corresp id="c001">&#x002A;Correspondence: Qianli Ma, <email>cqmql@163.com</email></corresp>
<fn fn-type="equal" id="fn002"><p><sup>&#x2020;</sup>These authors have contributed equally to this work and share first authorship</p></fn>
</author-notes>
<pub-date pub-type="epub">
<day>24</day>
<month>09</month>
<year>2025</year>
</pub-date>
<pub-date pub-type="collection">
<year>2025</year>
</pub-date>
<volume>12</volume>
<elocation-id>1666703</elocation-id>
<history>
<date date-type="received">
<day>15</day>
<month>07</month>
<year>2025</year>
</date>
<date date-type="accepted">
<day>10</day>
<month>09</month>
<year>2025</year>
</date>
</history>
<permissions>
<copyright-statement>Copyright &#x00A9; 2025 Wang, Liu, Zhang, Li and Ma.</copyright-statement>
<copyright-year>2025</copyright-year>
<copyright-holder>Wang, Liu, Zhang, Li and Ma</copyright-holder>
<license xlink:href="http://creativecommons.org/licenses/by/4.0/"><p>This is an open-access article distributed under the terms of the Creative Commons Attribution License (CC BY). The use, distribution or reproduction in other forums is permitted, provided the original author(s) and the copyright owner(s) are credited and that the original publication in this journal is cited, in accordance with accepted academic practice. No use, distribution or reproduction is permitted which does not comply with these terms.</p></license>
</permissions>
<abstract>
<sec>
<title>Introduction</title>
<p>Chronic Obstructive Pulmonary Disease (COPD) imposes a high global burden. Spirometry is the diagnostic gold standard but has accessibility barriers. Screening questionnaires provide a feasible alternative.</p>
</sec>
<sec>
<title>Objectives</title>
<p>To compare the diagnostic performance and robustness of six COPD screening questionnaires (LFQ: Lung Function Questionnaire; IPAG: International Primary Care Airways Group Questionnaire; Modified-IPAG; COPD-PS: COPD Population Screener Questionnaire; COPD-SQ: COPD Screening Questionnaire; SCSQ: The Salzburg COPD Screening Questionnaire) within a single cohort population, thereby providing evidence to support targeted screening for COPD.</p>
</sec>
<sec>
<title>Methods</title>
<p>This cross-sectional study enrolled adults &#x2265;40 years without prior asthma or non-COPD chronic lung diseases. Participants completed six screening questionnaires and spirometry. COPD was confirmed by pulmonologists. Receiver operating characteristic (ROC) curves were constructed for each questionnaire; sensitivity, specificity, accuracy (ACC), positive predictive value (PPV), negative predictive value (NPV), and area under the curve (AUC) were calculated. Dynamic variations in screening performance were simulated under different disease prevalence scenarios.</p>
</sec>
<sec>
<title>Results</title>
<p>Modified-IPAG and LFQ showed highest sensitivity (94.78%/91.79%) and NPV (98.11%/97.45%); COPD-PS and COPD-SQ had highest specificity (79.32%/87.05%) and PPV (43.50%/43.87%). AUC ranged 0.681 (SCSQ)&#x2013;0.796 (COPD-PS). Dynamic simulations revealed COPD-PS maintained stable ACC across prevalence (&#x0394;ACC = 0.06; &#x03B2; = &#x2212;0.018; <italic>P</italic> = 0.114), while SQ declined with increasing prevalence (&#x0394;ACC = 0.26; &#x03B2; = &#x2212;0.263; <italic>P</italic> &#x003C; 0.001).</p>
</sec>
<sec>
<title>Conclusion</title>
<p>A &#x201C;Scenario-Priority&#x201D; strategy is proposed: For rule-out screening, use high-sensitivity tools (Modified-IPAG/LFQ); for high-risk identification, prioritize robust COPD-PS; in low-prevalence regions (&#x003C;30%), use high-specificity SQ. This approach transcends the conventional &#x201C;tool-first&#x201D; static framework, delivering evidence-based support for precision COPD screening implementation.</p>
</sec>
</abstract>
<kwd-group>
<kwd>COPD screening</kwd>
<kwd>diagnostic accuracy</kwd>
<kwd>questionnaire comparison</kwd>
<kwd>prevalence effect</kwd>
<kwd>adaptive screening</kwd>
</kwd-group>
<counts>
<fig-count count="2"/>
<table-count count="4"/>
<equation-count count="0"/>
<ref-count count="34"/>
<page-count count="8"/>
<word-count count="5075"/>
</counts>
<custom-meta-wrap>
<custom-meta>
<meta-name>section-at-acceptance</meta-name>
<meta-value>Pulmonary Medicine</meta-value>
</custom-meta>
</custom-meta-wrap>
</article-meta>
</front>
<body>
<sec id="S1" sec-type="intro">
<title>1 Introduction</title>
<p>Chronic obstructive pulmonary disease (COPD) is a chronic respiratory disorder characterized by persistent airflow limitation, imposing a substantial global disease burden (<xref ref-type="bibr" rid="B1">1</xref>, <xref ref-type="bibr" rid="B2">2</xref>). As the third leading cause of death worldwide, COPD disproportionately affects low- and middle-income countries, accounting for 90% of premature COPD-related deaths (<xref ref-type="bibr" rid="B3">3</xref>). The 2019 global prevalence reached 10.3% (approximately 391.9 million cases) in adults aged 30&#x2013;79 years (<xref ref-type="bibr" rid="B4">4</xref>), while Chinese data report higher rates (13.7% in adults &#x2265;40 years) with significant regional disparities (<xref ref-type="bibr" rid="B5">5</xref>). As the disease progresses, symptoms such as dyspnea and restricted activity frequently lead to high disability-adjusted life years and diminished quality of life among COPD patients (<xref ref-type="bibr" rid="B6">6</xref>&#x2013;<xref ref-type="bibr" rid="B8">8</xref>).</p>
<p>Research indicates that early COPD screening enables smoking cessation interventions to delay lung function decline and reduces hospitalization costs associated with acute exacerbations (<xref ref-type="bibr" rid="B9">9</xref>&#x2013;<xref ref-type="bibr" rid="B11">11</xref>), demonstrating significant health economic value. Although spirometry remains the diagnostic gold standard for COPD (<xref ref-type="bibr" rid="B1">1</xref>), its utility as a population-wide screening tool is debated (<xref ref-type="bibr" rid="B12">12</xref>&#x2013;<xref ref-type="bibr" rid="B14">14</xref>). In resource-constrained primary care settings, spirometry faces substantial implementation barriers, including limited accessibility, high technical requirements, and potential suboptimal patient cooperation, resulting in underutilization of high-quality testing and diminishing its efficiency as a case-finding instrument (<xref ref-type="bibr" rid="B15">15</xref>&#x2013;<xref ref-type="bibr" rid="B17">17</xref>). In contrast, brief, user-friendly self-administered questionnaires offer a pragmatic alternative for identifying high-risk individuals requiring spirometry referral, leveraging advantages such as low cost, ease of operation, and capacity for dynamic symptom monitoring (e.g., dyspnea grading).</p>
<p>Although multiple studies have reported the diagnostic performance of COPD screening questionnaires, significant variability exists across different investigations (<xref ref-type="bibr" rid="B18">18</xref>&#x2013;<xref ref-type="bibr" rid="B22">22</xref>). This heterogeneity complicates end-users&#x2019; ability to determine which questionnaire optimally achieves the highest screening efficacy within specific target populations and clinical contexts. A key contributor to this dilemma is the pronounced dependence of questionnaire performance&#x2013;particularly PPV and NPV&#x2013;on the underlying disease prevalence of the target population. Previous evaluations predominantly assessed performance under single, fixed prevalence conditions, neglecting to examine diagnostic robustness across varying prevalence rates. Consequently, their findings demonstrate limited generalizability to real-world settings with divergent prevalence profiles, restricting the broader applicability of screening strategies across diverse implementation scenarios. Therefore, a systematic evaluation of COPD questionnaire performance within a unified cohort&#x2013;accounting for different usage scenarios and prevalence conditions&#x2013;is imperative to generate evidence-based support for precision-based screening strategies.</p>
</sec>
<sec id="S2" sec-type="materials|methods">
<title>2 Materials and methods</title>
<sec id="S2.SS1">
<title>2.1 Study design</title>
<p>A cross-sectional study was conducted among subjects referred for pre- and post-bronchodilator spirometry at the Respiratory Outpatient Clinic of Chongqing Songshan General Hospital between March 2021 and January 2023.</p>
</sec>
<sec id="S2.SS2">
<title>2.2 Participants</title>
<sec id="S2.SS2.SSS1">
<title>2.2.1 Inclusion criteria</title>
<p>Aged &#x2265;40 years; Voluntarily provided written informed consent; Completed six COPD screening questionnaires; Underwent post-bronchodilator spirometry.</p>
</sec>
<sec id="S2.SS2.SSS2">
<title>2.2.2 Exclusion criteria</title>
<p>Current acute exacerbation of respiratory disease; Inability to perform spirometry according to American Thoracic Society and the European Respiratory Society (ATS/ERS) technical standards or contraindications to spirometry; Cognitive or linguistic barriers precluding questionnaire completion.</p>
</sec>
</sec>
<sec id="S2.SS3">
<title>2.3 Data collection and questionnaires</title>
<p>Prior to spirometry testing, a trained coordinator administered an integrated questionnaire to participants. This instrument consolidated items from six established COPD screening tools: the LFQ, IPAG, Modified-IPAG, COPD-PS, COPD-SQ and SCSQ. Data collection encompassed three domains: (1) demographic characteristics including age, gender, height, and weight; (2) risk factors such as history of biomass fuel exposure, long-term exposure to dust or chemical particulates, allergy history, family history of respiratory diseases, and childhood chronic respiratory disease history; and (3) respiratory symptoms comprising cough, sputum production, dyspnea, and quality-of-life impacts attributable to respiratory problems. Body mass index (BMI) was derived from measured height and weight using standard formulae. Smoking exposure was quantified as pack-years, calculated by multiplying the number of cigarette packs smoked daily (standardized at 20 cigarettes per pack) by total years of smoking.</p>
<sec id="S2.SS3.SSS1">
<title>2.3.1 Questionnaires</title>
<sec id="S2.SS3.SSS1.Px1">
<title>2.3.1.1 Lung function questionnaire (LFQ)</title>
<p>Developed by Yawn et al. (<xref ref-type="bibr" rid="B23">23</xref>), this 5-item tool (age, smoking, wheezing, dyspnea, sputum) initially used binary responses (yes/no), with &#x2265;3 positive items indicating airflow limitation risk (AUC = 0.720; sensitivity 73.2%, specificity 58.2%). The validation study Hanania et al. (<xref ref-type="bibr" rid="B24">24</xref>) demonstrated that a 5-point scale (score 5&#x2013;25) with &#x2264;18 as the threshold achieved sensitivity 82.6%, specificity 47.8%, and ACC 54.3% (AUC = 0.652), significantly outperforming the binary format.</p>
</sec>
<sec id="S2.SS3.SSS1.Px2">
<title>2.3.1.2 COPD population screener questionnaire (COPD-PS)</title>
<p>Developed by Martinez et al. (<xref ref-type="bibr" rid="B25">25</xref>), including 5 items: age, smoking history, breathlessness, productive cough, and activity limitation due to breathing problems. When using a cutoff score of 5 on the COPD-PS, the sensitivity for identifying fixed airflow obstruction (AO) is 84.4%, specificity is 60.7%, PPV is 56.8%, NPV is 86.4%, and the AUC is 0.73.</p>
</sec>
<sec id="S2.SS3.SSS1.Px3">
<title>2.3.1.3 International primary care airways group questionnaire (IPAG)</title>
<p>Its core items originate from the case-finding version of the COPD Diagnostic Questionnaire (CDQ) developed by Price et al. (<xref ref-type="bibr" rid="B26">26</xref>, <xref ref-type="bibr" rid="B27">27</xref>) for smokers aged &#x2265;40 years. It comprises eight items: age, BMI, pack-years of smoking, weather-related cough, phlegm without a cold, morning phlegm, wheezing frequency, and allergy history (termed the IPAG 8-item questionnaire). The IPAG Working Group recommended &#x2265;17 as the screening threshold in its operational manual (2009) (<xref ref-type="bibr" rid="B28">28</xref>).</p>
</sec>
<sec id="S2.SS3.SSS1.Px4">
<title>2.3.1.4 Modified-IPAG</title>
<p>In 2016, Zhang Q et al. (<xref ref-type="bibr" rid="B29">29</xref>) systematically revised the IPAG questionnaire for the Chinese population by removing two low-discriminatory items (&#x201C;coughing up phlegm without a cold&#x201D; and &#x201C;morning phlegm&#x201D;), adjusting BMI scoring to Chinese standards (&#x003C;24, 24&#x2013;28, &#x2265;28), and adding five China-specific risk items: secondhand smoke exposure, coughing without a cold, shortness of breath, long-term dust/chemical exposure, and childhood chronic respiratory disease history (termed the IPAG 11-item questionnaire). The optimal screening threshold (&#x2265;17), determined by the ROC curve&#x2019;s inflection point, achieved 82.5% sensitivity and 72.9% specificity, significantly improving screening efficacy in the Chinese cohort.</p>
</sec>
<sec id="S2.SS3.SSS1.Px5">
<title>2.3.1.5 COPD screening questionnaire (COPD-SQ)</title>
<p>COPD Screening Questionnaire Developed by Zhou YM et al. (<xref ref-type="bibr" rid="B30">30</xref>). Based on China&#x2019;s 2002 national COPD epidemiological survey data, this instrument comprises seven items: age, smoking pack-years, BMI, cough, dyspnea, family history of respiratory diseases, and biomass fuel exposure. A screening threshold of &#x2265;16 is recommended (sensitivity 60.6%, specificity 85.2%, ACC 82.7%).</p>
</sec>
<sec id="S2.SS3.SSS1.Px6">
<title>2.3.1.6 The salzburg COPD screening questionnaire (SCSQ)</title>
<p>The Salzburg COPD Screening Questionnaire Developed by Austrian researchers Weiss et al. (<xref ref-type="bibr" rid="B31">31</xref>) based on the Burden of Obstructive Lung Diseases (BOLD) study cohort in Salzburg, comprises five items: smoking history (current/former/never), breathing problems severely limiting daily activities, health restrictions when climbing multiple flights of stairs, wheezing or whistling in the chest within the past 12 months, and coughing without a cold. A threshold of &#x2265;2 is recommended (sensitivity 69.1%, specificity 60.0%, PPV 23.2%).</p>
</sec>
</sec>
<sec id="S2.SS3.SSS2">
<title>2.3.2 Spirometry</title>
<p>All participants underwent spirometry testing using the MasterScreen Pneumo pulmonary function testing system (Jaeger, Germany).</p>
<p>The procedures strictly adhered to quality control standards established by the ATS/ERS (<xref ref-type="bibr" rid="B32">32</xref>, <xref ref-type="bibr" rid="B33">33</xref>). Subjects demonstrating a pre-bronchodilator forced expiratory volume in 1 s (FEV<sub>1</sub>) to forced vital capacity (FVC) ratio &#x003C; 0.7 received 400 &#x03BC;g salbutamol sulfate via metered-dose inhaler with spacer chamber, with post-bronchodilator spirometry repeated 15&#x2013;20 min after administration. Complete pre- and post-bronchodilator pulmonary function data were documented for all subjects.</p>
<p>According to the Global Initiative for Chronic Obstructive Lung Disease (GOLD) criteria (<xref ref-type="bibr" rid="B1">1</xref>), a post-bronchodilator FEV<sub>1</sub>/FVC ratio &#x003C; 0.7 indicates persistent airflow limitation. After exclusion of other diseases that may cause airflow limitation, this finding supports a clinical diagnosis of COPD.</p>
</sec>
</sec>
<sec id="S2.SS4">
<title>2.4 Statistical analysis</title>
<p>Descriptive statistics were employed to evaluate demographic characteristics and questionnaire scores. Continuous parametric variables were expressed as mean &#x00B1; standard deviation (SD), with between-group comparisons analyzed using independent samples <italic>t</italic>-tests. Categorical variables were presented as frequencies and percentages (%), with between-group comparisons assessed by chi-square tests. Using GOLD criteria as the diagnostic gold standard for COPD, ROC curves were constructed for each questionnaire. Sensitivity, specificity, ACC, PPV, NPV, and AUC were calculated for all screening instruments. Differences in ROC-AUC between questionnaires were analyzed using DeLong&#x2019;s test with Bonferroni correction for multiple comparisons. Linear regression analysis examined the correlation between screening ACC and disease prevalence. All statistical analyses were performed using R version 4.4.1 and MedCalc version 20.0. Statistical significance was set at <italic>p</italic> &#x003C; 0.05.</p>
</sec>
</sec>
<sec id="S3" sec-type="results">
<title>3 Results</title>
<sec id="S3.SS1">
<title>3.1 Participants characteristics</title>
<p>Among 811 initially recruited patients, 806 met the inclusion criteria and were taken to the final analysis. COPD prevalence was 16.63% (134/806). The mean age of the participants was 58.8 years (SD = 10.8), and 43.3% (349/806) were female. A diagnosis of COPD was significantly associated with male gender (83.6% vs. 16.5%, <italic>p</italic> &#x003C; 0.001), older (66.1 &#x00B1; 8.3 vs. 57.3 &#x00B1; 10.7 years, <italic>p</italic> &#x003C; 0.001), lower BMI (23.3 &#x00B1; 3.4 vs. 24.1 &#x00B1; 3.2, <italic>p</italic> = 0.007), high smoking pack-years (36.4 &#x00B1; 30.2 vs. 11.6 &#x00B1; 21.2, <italic>p</italic> &#x003C; 0.001), biomass fuel exposure (25.4% vs. 12.5%, <italic>p</italic> &#x003C; 0.001), long-term dust/chemical particle exposure (40.3% vs. 19.0%, <italic>p</italic> &#x003C; 0.001), and a history of childhood chronic respiratory diseases (21.6% vs. 11.0%, <italic>p</italic> &#x003C; 0.001).</p>
<p>By contrast, no significant association was observed with family history of respiratory diseases or allergy history (<italic>p</italic> &#x003E; 0.05).</p>
<p>All six questionnaires showed statistically significant score differences between groups (<italic>p</italic> &#x003C; 0.001). Complete data are shown in <xref ref-type="table" rid="T1">Table 1</xref> (all <italic>P</italic> &#x003C; 0.001).</p>
<table-wrap position="float" id="T1">
<label>TABLE 1</label>
<caption><p>General characteristics of the participants.</p></caption>
<table cellspacing="5" cellpadding="5" frame="box" rules="all">
<thead>
<tr>
<td valign="top" align="left">Characteristics</td>
<td valign="top" align="left">Total (<italic>N</italic> = 806)</td>
<td valign="top" align="left">Non-COPD (<italic>n</italic> = 672)</td>
<td valign="top" align="left">COPD (<italic>n</italic> = 134)</td>
<td valign="top" align="left"><italic>P-</italic>value</td>
</tr>
</thead>
<tbody>
<tr>
<td valign="top" align="left" colspan="5"><bold>Gender, <italic>n</italic> (%)</bold></td>
</tr>
<tr>
<td valign="top" align="left">&#x2003;Males</td>
<td valign="top" align="left">457 (56.7%)</td>
<td valign="top" align="left">345 (51.3%)</td>
<td valign="top" align="left">112 (83.6%)</td>
<td valign="top" align="left">&#x003C;0.001<bold><xref ref-type="table-fn" rid="t1fns1">&#x002A;</xref></bold></td>
</tr>
<tr>
<td valign="top" align="left">&#x2003;Females</td>
<td valign="top" align="left">349 (43.3%)</td>
<td valign="top" align="left">327 (48.7%)</td>
<td valign="top" align="left">22 (16.5%)</td>
<td/>
</tr>
<tr>
<td valign="top" align="left">Age (years), mean (SD)</td>
<td valign="top" align="left">58.8 (10.8)</td>
<td valign="top" align="left">57.3 (10.7)</td>
<td valign="top" align="left">66.1 (8.3)</td>
<td valign="top" align="left">&#x003C;0.001<xref ref-type="table-fn" rid="t1fnd1"><sup>&#x2020;</sup></xref></td>
</tr>
<tr>
<td valign="top" align="left">Height (cm), mean (SD)</td>
<td valign="top" align="left">162.5 (8.0)</td>
<td valign="top" align="left">162.5 (8.0)</td>
<td valign="top" align="left">162.5 (7.6)</td>
<td valign="top" align="left">0.944<xref ref-type="table-fn" rid="t1fnd1"><sup>&#x2020;</sup></xref></td>
</tr>
<tr>
<td valign="top" align="left">Weight (kg), mean (SD)</td>
<td valign="top" align="left">63.6 (11.1)</td>
<td valign="top" align="left">63.9 (11.0)</td>
<td valign="top" align="left">61.7 (11.4)</td>
<td valign="top" align="left">0.036<xref ref-type="table-fn" rid="t1fnd1"><sup>&#x2020;</sup></xref></td>
</tr>
<tr>
<td valign="top" align="left">BMI, mean (SD)</td>
<td valign="top" align="left">24.0 (3.2)</td>
<td valign="top" align="left">24.1 (3.2)</td>
<td valign="top" align="left">23.3 (3.4)</td>
<td valign="top" align="left">0.007<xref ref-type="table-fn" rid="t1fnd1"><sup>&#x2020;</sup></xref></td>
</tr>
<tr>
<td valign="top" align="left">Smoking pack-years, mean (SD)</td>
<td valign="top" align="left">15.7 (24.7)</td>
<td valign="top" align="left">11.6 (21.2)</td>
<td valign="top" align="left">36.4 (30.2)</td>
<td valign="top" align="left">&#x003C;0.001<xref ref-type="table-fn" rid="t1fnd1"><sup>&#x2020;</sup></xref></td>
</tr>
<tr>
<td valign="top" align="left">Biomass fuel exposure, n (%)</td>
<td valign="top" align="left">118 (14.6)</td>
<td valign="top" align="left">84 (12.5)</td>
<td valign="top" align="left">34 (25.4)</td>
<td valign="top" align="left">&#x003C;0.001<bold><xref ref-type="table-fn" rid="t1fns1">&#x002A;</xref></bold></td>
</tr>
<tr>
<td valign="top" align="left">Long-term exposure to dust or chemical particles, <italic>n</italic> (%)</td>
<td valign="top" align="left">182 (22.6)</td>
<td valign="top" align="left">128 (19.0)</td>
<td valign="top" align="left">54 (40.3)</td>
<td valign="top" align="left">&#x003C;0.001<bold><xref ref-type="table-fn" rid="t1fns1">&#x002A;</xref></bold></td>
</tr>
<tr>
<td valign="top" align="left">Allergy history, <italic>n</italic> (%)</td>
<td valign="top" align="left">57 (7.1)</td>
<td valign="top" align="left">42 (6.2)</td>
<td valign="top" align="left">15 (11.2)</td>
<td valign="top" align="left">0.064<bold><xref ref-type="table-fn" rid="t1fns1">&#x002A;</xref></bold></td>
</tr>
<tr>
<td valign="top" align="left">Family history of respiratory diseases, <italic>n</italic> (%)</td>
<td valign="top" align="left">236 (29.3)</td>
<td valign="top" align="left">195 (29.0)</td>
<td valign="top" align="left">41 (30.6)</td>
<td valign="top" align="left">0.793<bold><xref ref-type="table-fn" rid="t1fns1">&#x002A;</xref></bold></td>
</tr>
<tr>
<td valign="top" align="left">Childhood Respiratory Disease, <italic>n</italic> (%)</td>
<td valign="top" align="left">103 (12.8)</td>
<td valign="top" align="left">74 (11.0)</td>
<td valign="top" align="left">29 (21.6)</td>
<td valign="top" align="left">0.001<bold><xref ref-type="table-fn" rid="t1fns1">&#x002A;</xref></bold></td>
</tr>
<tr>
<td valign="top" align="center">LFQ</td>
<td valign="top" align="left">18.08 (3.77)</td>
<td valign="top" align="left">19.05 (3.00)</td>
<td valign="top" align="left">13.22 (3.49)</td>
<td valign="top" align="left">&#x003C;0.001<xref ref-type="table-fn" rid="t1fnd1"><sup>&#x2020;</sup></xref></td>
</tr>
<tr>
<td valign="top" align="center">Modified-IPAG</td>
<td valign="top" align="left">18.60 (7.90)</td>
<td valign="top" align="left">16.79 (6.78)</td>
<td valign="top" align="left">27.69 (6.79)</td>
<td valign="top" align="left">&#x003C;0.001<xref ref-type="table-fn" rid="t1fnd1"><sup>&#x2020;</sup></xref></td>
</tr>
<tr>
<td valign="top" align="center">COPD-PS</td>
<td valign="top" align="left">3.50 (2.31)</td>
<td valign="top" align="left">2.96 (1.97)</td>
<td valign="top" align="left">6.19 (2.01)</td>
<td valign="top" align="left">&#x003C;0.001<xref ref-type="table-fn" rid="t1fnd1"><sup>&#x2020;</sup></xref></td>
</tr>
<tr>
<td valign="top" align="center">IPAG</td>
<td valign="top" align="left">18.64 (6.37)</td>
<td valign="top" align="left">17.35 (5.72)</td>
<td valign="top" align="left">25.13 (5.43)</td>
<td valign="top" align="left">&#x003C;0.001<xref ref-type="table-fn" rid="t1fnd1"><sup>&#x2020;</sup></xref></td>
</tr>
<tr>
<td valign="top" align="center">COPD-SQ</td>
<td valign="top" align="left">10.80 (5.09)</td>
<td valign="top" align="left">9.83 (4.69)</td>
<td valign="top" align="left">15.66 (4.15)</td>
<td valign="top" align="left">&#x003C;0.001<xref ref-type="table-fn" rid="t1fnd1"><sup>&#x2020;</sup></xref></td>
</tr>
<tr>
<td valign="top" align="center">SCSQ</td>
<td valign="top" align="left">2.67 (2.43)</td>
<td valign="top" align="left">2.17 (2.08)</td>
<td valign="top" align="left">5.16 (2.50)</td>
<td valign="top" align="left">&#x003C;0.001<xref ref-type="table-fn" rid="t1fnd1"><sup>&#x2020;</sup></xref></td>
</tr>
</tbody>
</table>
<table-wrap-foot>
<fn id="t1fns1"><p><bold>&#x002A;</bold>Pearson &#x03C7;<sup>2</sup> test;</p></fn>
<fn id="t1fnd1"><p>&#x2020;Independent <italic>t</italic> test; SD, standard deviation; BMI, body mass index; COPD, chronic obstructive pulmonary disease; LFQ, lung function questionnaire; COPD-PS, COPD population screener questionnaire; IPAG, international primary care airways group questionnaire; COPD-SQ, COPD screening questionnaire; SCSQ, the salzburg COPD screening questionnaire.</p></fn>
</table-wrap-foot>
</table-wrap>
</sec>
<sec id="S3.SS2">
<title>3.2 Diagnostic performance of COPD screening questionnaires</title>
<p>At recommended cut-off values (<xref ref-type="table" rid="T2">Table 2</xref>), the AUC for the six questionnaires ranged from 0.681 (SCSQ) to 0.796 (COPD-PS). Modified-IPAG showed the highest sensitivity (94.78%) and NPV (98.11%), while COPD-SQ demonstrated the highest specificity (87.05%) and PPV (43.87%). Pairwise comparison of AUCs using the DeLong test with Bonferroni correction indicated that COPD-PS had significantly higher AUC than IPAG (<italic>P</italic> &#x003C; 0.001), COPD-SQ (<italic>P</italic> &#x003C; 0.001), and SCSQ (<italic>P</italic> &#x003C; 0.001). In contrast, no statistically significant differences were observed between COPD-PS and LFQ (<italic>P</italic> = 1.000), COPD-PS and Modified-IPAG (<italic>P</italic> = 0.130), Modified-IPAG and LFQ (<italic>P</italic> = 1.000), Modified-IPAG and COPD-SQ (<italic>P</italic> = 0.330), IPAG and COPD-SQ (<italic>P</italic> = 1.000), IPAG and SCSQ (<italic>P</italic> = 1.000), or COPD-SQ and SCSQ (<italic>P</italic> = 1.000) (<xref ref-type="table" rid="T3">Table 3</xref>).</p>
<table-wrap position="float" id="T2">
<label>TABLE 2</label>
<caption><p>Diagnostic performance of COPD screening questionnaires.</p></caption>
<table cellspacing="5" cellpadding="5" frame="box" rules="all">
<thead>
<tr>
<td valign="top" align="left">Questionnaire</td>
<td valign="top" align="center">Cut-off</td>
<td valign="top" align="center">Sen (%)</td>
<td valign="top" align="center">Spe (%)</td>
<td valign="top" align="center">PPV (%)</td>
<td valign="top" align="center">NPV (%)</td>
<td valign="top" align="center">ACC (%)</td>
<td valign="top" align="center">AUC</td>
</tr>
</thead>
<tbody>
<tr>
<td valign="top" align="left">LFQ</td>
<td valign="top" align="center">&#x2264;18</td>
<td valign="top" align="center">91.79</td>
<td valign="top" align="center">62.50</td>
<td valign="top" align="center">32.80</td>
<td valign="top" align="center">97.45</td>
<td valign="top" align="center">67.37</td>
<td valign="top" align="center">0.772</td>
</tr>
<tr>
<td valign="top" align="left">Modified- IPAG</td>
<td valign="top" align="center">&#x2265;17</td>
<td valign="top" align="center">94.78</td>
<td valign="top" align="center">54.02</td>
<td valign="top" align="center">29.13</td>
<td valign="top" align="center">98.11</td>
<td valign="top" align="center">60.79</td>
<td valign="top" align="center">0.744</td>
</tr>
<tr>
<td valign="top" align="left">COPD-PS</td>
<td valign="top" align="center">&#x2265;5</td>
<td valign="top" align="center">79.85</td>
<td valign="top" align="center">79.32</td>
<td valign="top" align="center">43.50</td>
<td valign="top" align="center">95.18</td>
<td valign="top" align="center">79.40</td>
<td valign="top" align="center">0.796</td>
</tr>
<tr>
<td valign="top" align="left">IPAG</td>
<td valign="top" align="center">&#x2265;17</td>
<td valign="top" align="center">91.79</td>
<td valign="top" align="center">47.92</td>
<td valign="top" align="center">26.00</td>
<td valign="top" align="center">96.70</td>
<td valign="top" align="center">55.21</td>
<td valign="top" align="center">0.699</td>
</tr>
<tr>
<td valign="top" align="left">COPD-SQ</td>
<td valign="top" align="center">&#x2265;16</td>
<td valign="top" align="center">50.75</td>
<td valign="top" align="center">87.05</td>
<td valign="top" align="center">43.87</td>
<td valign="top" align="center">89.86</td>
<td valign="top" align="center">81.02</td>
<td valign="top" align="center">0.689</td>
</tr>
<tr>
<td valign="top" align="left">SCSQ</td>
<td valign="top" align="center">&#x2265;2</td>
<td valign="top" align="center">89.55</td>
<td valign="top" align="center">46.73</td>
<td valign="top" align="center">25.10</td>
<td valign="top" align="center">95.73</td>
<td valign="top" align="center">53.85</td>
<td valign="top" align="center">0.681</td>
</tr>
</tbody>
</table>
<table-wrap-foot>
<fn><p>Sen, sensitivity; Spe, specificity; PPV, positive predictive value; NPV, negative predictive value; ACC, accuracy; AUC, area under the curve.</p></fn>
</table-wrap-foot>
</table-wrap>
<table-wrap position="float" id="T3">
<label>TABLE 3</label>
<caption><p>Pairwise comparison of AUCs (&#x002A;Adjusted <italic>P</italic> values).</p></caption>
<table cellspacing="5" cellpadding="5" frame="box" rules="all">
<thead>
<tr>
<td valign="top" align="left">Questionnaire</td>
<td valign="top" align="center">LFQ</td>
<td valign="top" align="center">Modified- IPAG</td>
<td valign="top" align="center">COPD-PS</td>
<td valign="top" align="center">IPAG</td>
<td valign="top" align="center">COPD-SQ</td>
<td valign="top" align="center">SCSQ</td>
</tr>
</thead>
<tbody>
<tr>
<td valign="top" align="left">LFQ</td>
<td valign="top" align="center">&#x2013;</td>
<td valign="top" align="center">&#x2013;</td>
<td valign="top" align="center">&#x2013;</td>
<td valign="top" align="center">&#x2013;</td>
<td valign="top" align="center">&#x2013;</td>
<td valign="top" align="center">&#x2013;</td>
</tr>
<tr>
<td valign="top" align="left">Modified- IPAG</td>
<td valign="top" align="center">1.0</td>
<td valign="top" align="center">&#x2013;</td>
<td valign="top" align="center">&#x2013;</td>
<td valign="top" align="center">&#x2013;</td>
<td valign="top" align="center">&#x2013;</td>
<td valign="top" align="center">&#x2013;</td>
</tr>
<tr>
<td valign="top" align="left">COPD-PS</td>
<td valign="top" align="center">1.0</td>
<td valign="top" align="center">0.130</td>
<td valign="top" align="center">&#x2013;</td>
<td valign="top" align="center">&#x2013;</td>
<td valign="top" align="center">&#x2013;</td>
<td valign="top" align="center">&#x2013;</td>
</tr>
<tr>
<td valign="top" align="left">IPAG</td>
<td valign="top" align="center">0.001</td>
<td valign="top" align="center">0.009</td>
<td valign="top" align="center">&#x003C;0.001</td>
<td valign="top" align="center">&#x2013;</td>
<td valign="top" align="center">&#x2013;</td>
<td valign="top" align="center">&#x2013;</td>
</tr>
<tr>
<td valign="top" align="left">COPD-SQ</td>
<td valign="top" align="center">0.009</td>
<td valign="top" align="center">0.330</td>
<td valign="top" align="center">&#x003C;0.001</td>
<td valign="top" align="center">1.0</td>
<td valign="top" align="center">&#x2013;</td>
<td valign="top" align="center">&#x2013;</td>
</tr>
<tr>
<td valign="top" align="left">SCSQ</td>
<td valign="top" align="center">&#x003C;0.001</td>
<td valign="top" align="center">0.011</td>
<td valign="top" align="center">&#x003C;0.001</td>
<td valign="top" align="center">1.0</td>
<td valign="top" align="center">1.0</td>
<td valign="top" align="center">&#x2013;</td>
</tr>
</tbody>
</table>
<table-wrap-foot>
<fn><p>&#x002A;Adjusted <italic>P</italic> values from DeLong test with Bonferroni correction (<italic>P</italic> &#x003C; 0.05 indicates statistical significance).</p></fn>
</table-wrap-foot>
</table-wrap>
</sec>
<sec id="S3.SS3">
<title>3.3 Dynamic changes in screening accuracy across prevalence levels</title>
<p>This study simulated the screening ACC of six questionnaires across a prevalence spectrum of 5%&#x2013;95% (<xref ref-type="fig" rid="F1">Figure 1</xref>). Linear regression analysis demonstrated significant positive associations between ACC and prevalence for LFQ (&#x03B2; = 0.200, 95% CI: 0.163&#x2013;0.237), Modified- IPAG (&#x03B2; = 0.293, 95% CI: 0.258&#x2013;0.328), IPAG (&#x03B2; = 0.329, 95% CI: 0.301&#x2013;0.357), and SCSQ (&#x03B2; = 0.313, 95% CI: 0.281&#x2013;0.345) (all Bonferroni-adjusted <italic>P</italic> &#x003C; 0.001). A significant negative association was observed for COPD-SQ (&#x03B2; = &#x2212;0.263, 95% CI: &#x2212;0.302 to &#x2212;0.224, <italic>P</italic> &#x003C; 0.001). No significant association was found for COPD-PS (&#x03B2; = &#x2212;0.018, 95% CI: &#x2212;0.041&#x2013;0.005, <italic>P</italic> = 0.114).</p>
<fig id="F1" position="float">
<label>FIGURE 1</label>
<caption><p>Screening performance of six COPD questionnaires across prevalence levels.</p></caption>
<alt-text>Line graphs comparing six metrics (Sensitivity, Specificity, Positive Predictive Value, Negative Predictive Value, Area Under Curve, and Accuracy) across different prevalence levels for COPD-PS, IPAG, Modified-IPAG, COPD-SQ, LFQ, and SCSQ. Each metric shows varying trends with distinct color-coded lines for each assessment method.</alt-text>
<graphic mimetype="image" mime-subtype="tiff" xlink:href="fmed-12-1666703-g001.tif"/>
</fig>
<p>The absolute ACC fluctuation (&#x0394;ACC, maximum-minimum difference) ranged from 0.06 (COPD-PS) to 0.35 (IPAG), with values of 0.24 (LFQ), 0.31 (Modified- IPAG), 0.26 (COPD-SQ), and 0.33 (SCSQ). Complete regression statistics are presented in <xref ref-type="table" rid="T4">Table 4</xref>.</p>
<table-wrap position="float" id="T4">
<label>TABLE 4</label>
<caption><p>Regression analysis of screening accuracy against prevalence.</p></caption>
<table cellspacing="5" cellpadding="5" frame="box" rules="all">
<thead>
<tr>
<td valign="top" align="center">Questionnaire</td>
<td valign="top" align="center">&#x0394;ACC</td>
<td valign="top" align="center">&#x03B2; (Slope)</td>
<td valign="top" align="center">95% CI for &#x03B2;</td>
<td valign="top" align="center"><italic>P-value<xref ref-type="table-fn" rid="t4fna"><sup>a</sup></xref>
</italic></td>
</tr>
</thead>
<tbody>
<tr>
<td valign="top" align="center">LFQ</td>
<td valign="top" align="center">0.24</td>
<td valign="top" align="center">0.200</td>
<td valign="top" align="center">(0.163, 0.237)</td>
<td valign="top" align="center">&#x003C;0.001</td>
</tr>
<tr>
<td valign="top" align="center">Modified-IPAG</td>
<td valign="top" align="center">0.31</td>
<td valign="top" align="center">0.293</td>
<td valign="top" align="center">(0.258, 0.328)</td>
<td valign="top" align="center">&#x003C;0.001</td>
</tr>
<tr>
<td valign="top" align="center">COPD-PS</td>
<td valign="top" align="center">0.06</td>
<td valign="top" align="center">&#x2212;0.018</td>
<td valign="top" align="center">(&#x2212;0.041, 0.005)</td>
<td valign="top" align="center">0.114</td>
</tr>
<tr>
<td valign="top" align="center">IPAG</td>
<td valign="top" align="center">0.35</td>
<td valign="top" align="center">0.329</td>
<td valign="top" align="center">(0.301, 0.357)</td>
<td valign="top" align="center">&#x003C;0.001</td>
</tr>
<tr>
<td valign="top" align="center">COPD-SQ</td>
<td valign="top" align="center">0.26</td>
<td valign="top" align="center">&#x2212;0.263</td>
<td valign="top" align="center">(&#x2212;0.302, &#x2212;0.224)</td>
<td valign="top" align="center">&#x003C;0.001</td>
</tr>
<tr>
<td valign="top" align="center">SCSQ</td>
<td valign="top" align="center">0.33</td>
<td valign="top" align="center">0.313</td>
<td valign="top" align="center">(0.281, 0.345)</td>
<td valign="top" align="center">&#x003C;0.001</td>
</tr>
</tbody>
</table>
<table-wrap-foot>
<fn><p>&#x0394;ACC, Absolute performance fluctuation, calculated as the difference between maximum and minimum ACC; &#x03B2;, Regression coefficient indicating the change in ACC per unit increase in prevalence;</p></fn>
<fn id="t4fna"><p>a, Two-tailed <italic>t</italic>-test was used to assess whether &#x03B2; significantly differed from zero (significance level &#x03B1; = 0.05), with Bonferroni correction for multiple comparisons.</p></fn>
</table-wrap-foot>
</table-wrap>
</sec>
</sec>
<sec id="S4" sec-type="discussion">
<title>4 Discussion</title>
<p>This study conducted a cross-sectional comparison of the static diagnostic performance of six commonly used COPD screening questionnaires (LFQ, Modified-IPAG, COPD-PS, IPAG, COPS-SQ, SCSQ) within a single high-risk cohort (COPD detection rate: 16.63%). Innovatively, by dynamically simulating a wide range of prevalence rates (5%&#x2013;95%), it systematically quantified the sensitivity of each questionnaire&#x2019;s screening accuracy to changes in prevalence (i.e., &#x201C;robustness&#x201D;). The results revealed distinct response patterns in the performance of different COPD screening questionnaires to dynamic changes in prevalence.</p>
<p>The most striking finding was the exceptional robustness demonstrated by the COPD-PS. In the static assessment, PS showed a balanced diagnostic performance with sensitivity (79.85%) and specificity (79.32%) (AUC 0.796). More crucially, under dynamic simulation across varying prevalence rates, its screening accuracy exhibited minimal fluctuation (&#x0394;ACC = 0.06; &#x03B2; = &#x2212;0.018, <italic>P</italic> = 0.114). This indicates that COPS-PS&#x2019;s performance remains relatively stable across different prevalence scenarios, largely unaffected by the level of prevalence in the target screening population. This universal robustness likely stems from its balanced sensitivity and specificity (both &#x2248;79%). Furthermore, its items focus on core risk factors (age, smoking history) and core symptoms (breathlessness, productive cough, activity limitation) with globally recognized associations to COPD (<xref ref-type="bibr" rid="B1">1</xref>, <xref ref-type="bibr" rid="B34">34</xref>), and it has undergone rigorous cognitive testing to ensure consistent comprehension across diverse populations (<xref ref-type="bibr" rid="B25">25</xref>).</p>
<p>In stark contrast to COPS-PS, other questionnaires exhibited significant &#x201C;scenario dependency.&#x201D; Although the COPD-SQ questionnaire achieved the highest specificity (87.05%) and the lowest sensitivity (50.75%) in the static assessment (a pattern maintained in the dynamic evaluation), its accuracy showed a sharp decline as prevalence increased (&#x03B2; = &#x2212;0.263, <italic>P</italic> &#x003C; 0.001), with a substantial fluctuation magnitude of 26% (&#x0394;ACC = 0.26). This makes COPD-SQ the optimal tool for low-prevalence scenarios. When the estimated prevalence is below 30%, its high specificity effectively controls false positives and unnecessary referrals while maintaining the highest accuracy (ACC &#x003E; 80%). However, its accuracy significantly decreases in high-prevalence scenarios (&#x003E;50%). Conversely, the Modified-IPAG and LFQ questionnaires, leveraging their ultra-high sensitivity (94.78% and 91.79%, respectively) and NPV (98.11% and 97.45%, respectively), performed optimally for rule-out screening, minimizing missed diagnoses (false negatives). It is important to note, however, that their accuracy improves with increasing prevalence (Modified-IPAG &#x03B2; = 0.293, LFQ &#x03B2; = 0.200, both <italic>P</italic> &#x003C; 0.001), and their fluctuation range is also larger (&#x0394;ACC = 0.31 and 0.24, respectively). This implies that in very low prevalence scenarios, their relatively lower specificity may lead to an increased false positive rate. The IPAG and SCSQ performed relatively poorly in both this study and the dynamic simulations (lower AUC, poor robustness), highlighting inherent limitations of the tools or insufficient validation.</p>
<p>Based on a comprehensive analysis of the static performance characteristics and dynamic robustness of the six screening questionnaires, this study proposes a &#x201C;Scenario-First&#x201D; adaptive screening strategy for COPD. Specifically, when the core objective is &#x201C;ruling out COPD&#x201D; (prioritizing minimizing missed diagnosis risk), such as during large-scale initial screening in primary care or in settings with extremely limited referral resources needing rapid identification of individuals highly unlikely to have COPD to conserve advanced diagnostics, the Modified-IPAG or LFQ questionnaires should be prioritized; leveraging their ultra-high sensitivity (both &#x003E;90%) and NPV (both &#x003E;97%), these efficiently identify non-COPD individuals, minimizing missed diagnoses, though this may result in a higher false positive rate manageable through subsequent spirometry. Conversely, when the core objective is &#x201C;ruling in COPD or identifying high-risk populations&#x201D; (prioritizing referral accuracy and controlling false positives), such as during pre-referral screening in specialist clinics or screening high-exposure groups (e.g., smokers, occupational dust), the choice must consider estimated prevalence: if prevalence is low (&#x003C;30%), the COPD-SQ questionnaire is optimal due to its outstanding high specificity (&#x003E;87%), effectively reducing false positives and unnecessary referrals; if prevalence is high (&#x2265;30%), difficult to determine, likely to fluctuate significantly (e.g., respiratory clinic patients, high-exposure occupations), or a more stable tool is needed, the COPD-PS questionnaire should be prioritized, as it maintains relatively good specificity and PPV at high prevalence (outperforming COPD-SQ&#x2019;s sharp decline) and its exceptional robustness makes it the &#x201C;safe choice&#x201D; and versatile first-line tool for uncertain or variable contexts. Furthermore, for institutions needing a single, universal tool to adapt to diverse scenarios or simplify processes, COPD-PS is undoubtedly the most reliable and adaptable choice due to its exceptional robustness. This strategy transcends the limitations of traditional comparisons based solely on single, fixed prevalence scenarios. Its core principle lies in precisely matching the optimal screening tool to the specific screening objective and the epidemiological background of the target population (primarily estimated prevalence), providing actionable, evidence-based decision-making support for clinical and public health practice (<xref ref-type="fig" rid="F2">Figure 2</xref>).</p>
<fig id="F2" position="float">
<label>FIGURE 2</label>
<caption><p>Adaptive COPD screening protocol based on purpose and population prevalence.</p></caption>
<alt-text>Flowchart for initiating COPD screening. It begins with determining the screening purpose: rule out COPD with high sensitivity or rule in COPD to identify high-risk patients. For ruling out, use Modified-IPAG or LFQ. For ruling in, consider estimated prevalence: less than thirty percent leads to using COPD-SQ, while thirty percent or more, or unknown, leads to needing a single universal tool, then using COPD-PS.</alt-text>
<graphic mimetype="image" mime-subtype="tiff" xlink:href="fmed-12-1666703-g002.tif"/>
</fig>
</sec>
<sec id="S5">
<title>5 Limitations</title>
<p>However, this study has certain limitations. Firstly, the prevalence simulation assumed a linear effect, whereas real-world COPD prevalence may exhibit non-linear patterns. Secondly, the study is based on single-center data; future external validation in multi-center cohorts is warranted. Finally, the cultural adaptation of questionnaire items and participants&#x2019; comprehension ability may also impact performance, a common challenge for all self-administered screening tools. Future research could explore integrating risk prediction models with questionnaire results to develop more intelligent dynamic decision support tools and evaluate the cost-effectiveness and implementation feasibility of this strategy in real-world application settings.</p>
</sec>
<sec id="S6" sec-type="conclusion">
<title>6 Conclusion</title>
<p>By dynamically simulating prevalence rates, this study quantitatively revealed a key reason for the heterogeneity observed in the diagnostic performance of COPD screening questionnaires across previous studies: the significant influence of target population prevalence on tool performance. Based on this insight, we innovatively propose a &#x201C;Scenario-First&#x201D; screening strategy. This strategy dynamically matches the optimal tool based on estimated prevalence and the screening objective, thereby transcending the limitations of the traditional &#x201C;tool-first&#x201D; static framework and providing an evidence-based decision-making foundation for addressing heterogeneity in screening scenarios.</p>
</sec>
</body>
<back>
<sec id="S7" sec-type="data-availability">
<title>Data availability statement</title>
<p>The original contributions presented in this study are included in this article/supplementary material, further inquiries can be directed to the corresponding author/s.</p>
</sec>
<sec id="S8" sec-type="ethics-statement">
<title>Ethics statement</title>
<p>The studies involving humans were approved by Ethics Committee of Chongqing Songshan General Hospital. The studies were conducted in accordance with the local legislation and institutional requirements. The participants provided their written informed consent to participate in this study.</p>
</sec>
<sec id="S9" sec-type="author-contributions">
<title>Author contributions</title>
<p>QW: Conceptualization, Formal analysis, Investigation, Methodology, Writing &#x2013; original draft. LL: Conceptualization, Formal analysis, Investigation, Methodology, Writing &#x2013; original draft. QZ: Data curation, Investigation, Methodology, Software, Validation, Writing &#x2013; review &#x0026; editing. HL: Project administration, Supervision, Writing &#x2013; review &#x0026; editing. QM: Conceptualization, Project administration, Supervision, Writing &#x2013; review &#x0026; editing.</p>
</sec>
<sec id="S10" sec-type="funding-information">
<title>Funding</title>
<p>The author(s) declare that no financial support was received for the research and/or publication of this article.</p>
</sec>
<ack><p>We thank all patients who participated in this study.</p>
</ack>
<sec id="S11" sec-type="COI-statement">
<title>Conflict of interest</title>
<p>The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest.</p>
</sec>
<sec id="S12" sec-type="ai-statement">
<title>Generative AI statement</title>
<p>The author(s) declare that no Generative AI was used in the creation of this manuscript.</p>
<p>Any alternative text (alt text) provided alongside figures in this article has been generated by Frontiers with the support of artificial intelligence and reasonable efforts have been made to ensure accuracy, including review by the authors wherever possible. If you identify any issues, please contact us.</p>
</sec>
<sec id="S13" sec-type="disclaimer">
<title>Publisher&#x2019;s note</title>
<p>All claims expressed in this article are solely those of the authors and do not necessarily represent those of their affiliated organizations, or those of the publisher, the editors and the reviewers. Any product that may be evaluated in this article, or claim that may be made by its manufacturer, is not guaranteed or endorsed by the publisher.</p>
</sec>
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