The emergence of the coronavirus disease 2019 (COVID-19) pandemic has resulted in a worldwide public health crisis (World Health Organization, 2020a,c), with sudden alterations to daily routines stemming from restrictions on social interactions, physical distancing measures, and isolation protocols potentially leading to psychological harm, including feelings of loneliness, fear, anxiety, and depression (Brooks et al., 2020; Lee, 2020; Luo M. et al., 2020; Talevi et al., 2020; Dorri et al., 2021). Studies have shown that COVID-19 had a negative effect on the quality of life (QoL) and psychological health, such as anxiety and depression (Brooks et al., 2020; Luo M. et al., 2020; Talevi et al., 2020; Dorri et al., 2021), as reflected by the new term “Corona Blues” (combining COVID-19 and blues, meaning depression) (Lee, 2020). A study in China with 1593 participants aged ≥18 years reported that those affected by quarantine had a higher prevalence of anxiety (12.9% vs. 6.7%) and depression (22.4% vs. 11.9%) than those unaffected by quarantine during the COVID-19 pandemic (Lei et al., 2020). Moreover, according to a study from the US including 1441 adults aged ≥18 years, the prevalence of depressive symptoms during the pandemic increased threefold to 27.8% compared with the prevalence obtained by the 2017–2018 National Health and Nutrition Examination Survey that included data on depressive symptoms of 5065 participants (Ettman et al., 2020). In South Korea, the Korean Society of Traumatic Stress Studies conducted a COVID-19 National Mental Health Survey, which revealed that the prevalence of suicidal ideation in June 2022 was 12.7%, which remained elevated in comparison to the 9.7% recorded in March 2020, during the initial phase of the COVID-19 outbreak (Ministry of Health and Welfare, 2022). Additionally, a one-year analysis of anxiety and depression levels following the initial COVID-19 outbreak reported a 55.8% prevalence, representing an 8.3% increase from 2020 (Lee and Kim, 2021). Consequently, in light of these findings, the World Health Organization (WHO) has emphasized the necessity for providing psychosocial support to address the mental burden associated with the COVID-19 pandemic (World Health Organization, 2020b).

The COVID-19 outbreak has also overloaded the healthcare system (e.g., due to limited manpower due to infection among healthcare workers, and shortages of hospital beds, equipment, or medicine) (Jazieh et al., 2020; Ennab and Ibdah, 2021; Romano et al., 2021; Shin et al., 2021). Indeed, some hospitals were forced to suspend regular healthcare services temporarily to respond to COVID-19 (Jazieh et al., 2020; Breast Screening Working Group (WG2) of the COVID-19 and Cancer Global Modelling Consortium et al., 2021), and patients have avoided hospital visits to limit the risk of COVID-19 infection (Cheng et al., 2021; Hammad et al., 2021; Kim et al., 2021). The above circumstances contributed to delays in diagnosis, management, or treatment of disease to some extent (de Joode et al., 2020; Jazieh et al., 2020; Breast Screening Working Group (WG2) of the Covid-19 and Cancer Global Modelling Consortium et al., 2021). Patients with chronic diseases such as hypertension, dyslipidemia, diabetes, cerebrovascular disease, heart disease, or cancer–collectively referred to as patients with underlying medical conditions, who have a higher risk of developing serious illness due to COVID-19 (Aggarwal et al., 2020; Dai et al., 2020; Liang et al., 2020; Zhou et al., 2020; Centers for Disease Control and Prevention, 2022c) might experience psychological burden (de Joode et al., 2020; Kayikcioglu et al., 2020; Wang Y. et al., 2020; Kim and Kim, 2022a,c; Ozkan et al., 2022). For example, a retrospective study in the UK analyzed the impact of COVID-19 on patient-reported health outcomes at a 30-day follow-up after hospitalization for acute stroke (Ozkan et al., 2022). Patients hospitalized during the pandemic (n = 95) had exacerbation of anxiety, depression, fatigue, pain, and sleep disturbance and reduced social participation and physical function compared with those hospitalized before the COVID-19 pandemic (n = 106) (Ozkan et al., 2022). In addition, a study conducted in Turkey assessing the impact of the COVID-19 pandemic on 169 patients with a previous history of premature myocardial infarction indicated that about two-thirds of the study patients reported an increased anxiety level (Kayikcioglu et al., 2020).

The QoL is a multidimensional concept that includes the subjective health status that an individual perceives, and health-related quality of life (HRQoL) can be useful for setting health goals and measuring prognosis among clinical patients (Yun et al., 2004; Nam et al., 2007; Centers for Disease Control and Prevention, 2018). Depression is one of the most seriously considered diseases worldwide, and it is also a risk factor for chronic diseases (Keck, 2010). In addition, the Patient Health Questionnaire-9 (PHQ-9) is widely used as a screening tool to detect depression and depressive symptoms (Park et al., 2010). Given the significance of evaluating the impact of the COVID-19 pandemic on HRQoL and depressive symptoms, particularly in individuals with chronic conditions, it is crucial to conduct assessments in order to establish systematic strategies for preserving and promoting HRQoL and mental well-being for both the population with chronic diseases and the general population. Several studies have reported the mental health of patients with chronic diseases since the COVID-19 outbreak using data from 2020. However, some analyses were without data on mental health status before the pandemic (Ahn et al., 2020; Kim et al., 2021; Kim and Kim, 2022c), while others focused on a specific sex group or on patients with a specific type of cancer (Park et al., 2022; Kim and Kim, 2022b).

In this study, our objective was to comparatively examine the impact of the COVID-19 pandemic on the HRQoL and depressive symptoms in patients with chronic diseases and the general population in South Korea, by utilizing the Korea National Health and Nutrition Examination Survey (KNHANES) 2017–2020, an annual nationally representative survey. We aimed to achieve this by comparing data collected pre-pandemic and during the pandemic period.

The current study examined data from the KNHANES 2017–2020 to compare the HRQoL levels and depressive symptoms among patients with chronic diseases and the general population before and during the COVID-19 pandemic. The analysis revealed that the HRQoL level was significantly lower in patients with chronic diseases compared to the general population both before and during the COVID-19 pandemic. Furthermore, patients with chronic diseases had significantly lower HRQoL levels in the anxiety/depression dimension during the COVID-19 pandemic in comparison to the pre-pandemic period. Additionally, patients with chronic diseases were more likely to experience depressive symptoms during the COVID-19 pandemic. In contrast, the general population did not exhibit a significant difference in the prevalence of depressive symptoms before and during the COVID-19 pandemic.

Previous research has reported that individuals with chronic diseases experience a negative impact on their QoL due to the prolonged nature of treatment and management, and that chronic diseases and mental health are interrelated (Chapman et al., 2005; Calvert et al., 2012; Megari, 2013; Ryoung and Byung-Deog, 2014; Cho, 2021; Centers for Disease Control and Prevention, 2022a). Consistent with these findings, this study revealed that compared to the general population, patients with chronic diseases exhibited lower HRQoL levels in all dimensions, both before and during the COVID-19 pandemic. Furthermore, the COVID-19 pandemic may exacerbate the risk for depression among individuals with chronic illnesses (Chen et al., 2020; Özdin and Bayrak Özdin, 2020; Luo Y. et al., 2020; Wang C. et al., 2020). According to a meta-analysis to assess the levels and prevalence of anxiety, distress, and stress in patients with diabetes during the COVID-19 pandemic, the prevalence of anxiety in type 2 diabetes patients was 20 and 36% in diabetes distress (García-Lara et al., 2022), which were higher than those in the pre-pandemic period [18% (Chaturvedi et al., 2019) and 29.4% (Huynh et al., 2021), respectively]. Similarly, a study in China on 658 patients with breast cancer found that severe anxiety and depression during the COVID-19 pandemic were 8.9 and 9.3%, respectively. This was higher than the results of previous studies of breast cancer patients in China before the COVID-19 pandemic (severe anxiety = 3.5%, moderate to severe depression = 3.5%) (Juanjuan et al., 2020; Lan et al., 2020).

Patients with chronic diseases with weakened immune systems have been identified as a high-risk group for severe COVID-19 infection and its related complications (Centers for Disease Control and Prevention, 2022c), as reported in studies on cancer patients (Dai et al., 2020; Liang et al., 2020; Ofori-Asenso et al., 2020). Therefore, individuals with chronic illnesses may experience increased psychological anxiety due to the fear of COVID-19 exposure. Additionally, disruptions to medical care caused by the outbreak of COVID-19, such as delays or suspensions in testing and treatment (de Joode et al., 2020; Jazieh et al., 2020; Breast Screening Working Group (WG2) of the Covid-19 and Cancer Global Modelling Consortium et al., 2021), are likely to have added a significant mental burden on patients with chronic diseases who require continuous treatment (Guven et al., 2020; Singhai et al., 2020; Kim et al., 2021). According to a study that analyzed the impact of the COVID-19 lockdown on patients with chronic diseases, it was reported that 42% of 181 patients missed regular testing (Saqib et al., 2020). Indeed, a study in China on 141 cancer outpatients reported that 41.8% experienced a delay in treatment, 60.3% feared visiting a hospital, and 85.1% were concerned about treatment delay (Liu et al., 2021). Similarly, a study on 154 patients with breast cancer reported that 18.8% of the patients experienced changes in treatment due to COVID-19, and those who experienced a treatment plan change had higher levels of depression than those who did not (Kim and Kim, 2022b).

Meanwhile, the average age of the chronic disease patients in this study were 64 years old, including mainly the elderly. Elderly individuals have a higher likelihood of developing chronic diseases (National Cancer Information Center, 2019; Korea Disease Control and Prevention Agency, 2020b, 2021; Statistics Korea, 2021). The elderly population, like patients with pre-existing conditions, is more vulnerable to COVID-19, and mortality rates due to COVID-19 are known to be higher than those reported for younger age groups (Wang L. et al., 2020; Centers for Disease Control and Prevention, 2022b,c). Indeed, according to a previous study among the elderly, the prevalence of clinically significant depressive symptoms among older adults increased to 19.8% during the COVID-19 pandemic, as compared to 7.2% before the pandemic onset (Briggs et al., 2021). Moreover, a deeper sense of isolation due to the temporary closure of senior welfare facilities and restrictions on social activities and social exchange since the COVID-19 pandemic could increase the emotional burden on the elderly (Shin et al., 2020). It is also believed that restrictions on visitors through strict control measures in nursing homes during the COVID-19 pandemic could negatively affect the mental health of the elderly in need of care (Chee, 2020).

Despite these interesting findings, the present study had some limitations. Firstly, while potential confounding factors were adjusted through the review of previous studies and a preliminary analysis, some unmeasured or unknown residual confounding factors (e.g., cancer stage, treatment type, treatment stage, and disease severity) that may affect the HRQoL and depressive symptoms of patients with chronic diseases may still exist. Secondly, this study analyzed the period after the COVID-19 pandemic outbreak by limiting it to 2020. There are regional differences in the timing of the COVID-19 epidemic, and HRQoL and the mental health status of patients with chronic diseases and the general population may change according to the different stages of the COVID-19 pandemic. Thus, it is necessary to investigate the long-term effects of COVID-19 on patients with chronic diseases and the general population. Thirdly, the present study was a cross-sectional study, and thus, the causal relationship between the HRQoL and depressive symptoms and COVID-19 could not be identified. Finally, in 2020, the number of participants decreased by about 750 compared with that in the last year due to the COVID-19 pandemic, and information about the HRQoL and depressive symptoms was collected through surveys. Thus, non-differential misclassification errors might have occurred due to these limitations. However, the KNHANES provides clear guidelines for health surveys (Korea Disease Control and Prevention Agency, 2020a), and all surveys were conducted in the same way as in 2017–2019 with the aid of trained staff to minimize the possibility of errors. Despite these limitations, the present study used highly reliable national sample data to analyze the HRQoL and depressive symptoms of Korean patients with chronic diseases and the general population before and during the COVID-19 pandemic.

Given the prolonged nature of the current pandemic, it is crucial to develop healthcare system guidelines for high-risk groups for infectious diseases. Our findings underscore the importance of enhancing the healthcare service environment to provide adequate psychosocial support during the COVID-19 pandemic, as well as fortifying the healthcare system in anticipation of potential future pandemics. Although we utilized the most up-to-date data available for analysis, we could only capture the initial phase of the COVID-19 outbreak. Therefore, follow-up studies are imperative to gain a more comprehensive understanding of the long-term negative effects of COVID-19 on patients with chronic illnesses, particularly with regards to the prolonged impact on HRQoL and mental health by incorporating data collected since 2020, as the pandemic is still ongoing. Finally, future studies should also investigate the effect of contracting COVID-19, by comparing patients with and without COVID-19 experience and examine the impact of changes in access and speed of care on patients’ mental health.

Publicly available datasets were analyzed in this study. This data can be found at: https://knhanes.kdca.go.kr/knhanes/main.do.

The studies involving human participants were reviewed and approved by Institutional Review Board of the Korea Disease Control and Prevention Agency. The patients/participants provided their written informed consent to participate in this study.

YP contributed to the writing the original draft, formal analysis, visualization, and software. KP contributed to the conceptualization, supervision, project administration, resources, funding acquisition, validation, and discussion, along with editing the manuscript. All authors have read and agreed to the final version of the manuscript.

This research was supported by the National Research Foundation of Korea grant funded by the Korea government (grant number: NRF-2021R1A2C1007869). The funding sponsor had no role in the study design; collection, analysis, and interpretation of data; writing of the report; and the decision to submit the article for publication.

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.

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.