In 2023, 17,209 inpatient cases were recorded with a PCS diagnosis, corresponding to an incidence of 48.9 per 100,000 inhabitants (Figure 1). Among them, 6,856 (40%) were male and 10,353 (60%) were female, with the highest prevalence observed in the 55–60 age group (Figure 2). The mean length of stay (LOS) for hospitalized PCS patients was 8.3 days, with a standard deviation of 11.6 days. LOS showed a right-skewed distribution. The median LOS was 7.1 days [interquartile range (IQR): 3.9–7.9 days].

A total of 1,945 distinct primary diagnoses were associated with PCS. The most frequently documented conditions included chronic fatigue syndrome, dyspnea, malaise, and fatigue, alongside other common diagnoses such as fibromyalgia, chronic pain disorders, pneumonia, and dizziness (Table 1).

The most commonly performed procedures involved respiratory diagnostics, such as whole-body plethysmography, thoracic CT with contrast, and computer-assisted 3D image analysis. Additional frequent procedures included CO diffusion capacity testing, cranial imaging, and care dependency assessments. Neurological evaluations, including electroencephalography (EEG) and neurography, were also frequently documented, alongside therapeutic interventions such as geriatric rehabilitation and tracheobronchoscopy (Table 2). This indicates that while PCS frequently leads to hospitalization, severe functional dependency affects a smaller subset of patients.

All distributional measures were derived from DRG-level mean values weighted by the number of cases per DRG, as patient-level distributions are not available in the InEK Data Browser. The most frequently coded G-DRG was Z65Z (Complaints, Symptoms, Other Anomalies, and Follow-up Treatment), accounting for 17.7% of cases (3,039 patients). The mean reimbursement per inpatient case was €3,947.97, with substantial variability across DRG categories (standard deviation: €916.28), reflecting heterogeneity in clinical complexity and resource utilization. Extrapolating these costs to the 17,209 recorded PCS patients, the total direct healthcare costs for PCS treatment were estimated at €67,940,616.

With over 17,000 recorded hospitalizations, PCS remains a clinically relevant condition in Germany. The demographic distribution of hospitalized PCS patients reveals a notable gender imbalance, with women comprising 60% of cases. This aligns with international findings suggesting higher susceptibility to long-term post-viral sequelae among females (10, 11). Other studies conducted in different countries report around 53% to be female (12, 13). Possible explanations to the greater extent of females developing PCS can be found in the literature pointing towards sex-specific innate and adaptive immune correlates (14, 15). The age group most affected was between 55 and 60 years, consistent with prior data identifying middle-aged and older adults as high-risk populations for prolonged post-infectious sequelae. Notably, compared to prior data published, the number of hospitalized cases decreased from 29,808 by 43% (9).

The clinical presentation of PCS was highly diverse, with a variety of primary diagnoses documented. The most frequent included chronic fatigue syndrome, dyspnea, malaise, fibromyalgia, chronic pain, and neurocognitive symptoms—indicating multi-system involvement. These are consistent with existing literature on PCS symptomatology (16–18).

Importantly, these findings reflect not only residual effects of acute COVID-19, but also secondary complications such as autonomic dysfunction, post-exertional malaise, and psychological distress. This constellation of symptoms often co-occurs with pre-existing conditions or is exacerbated by them, highlighting the need for a multidisciplinary treatment approach that integrates pulmonology, neurology, internal medicine, pain management, and psychosomatic care. Rehabilitation strategies and coordinated outpatient follow-up are likely essential to address the persistent functional impairments in this patient population (19, 20).

The wide range of medical procedures underscores the substantial diagnostic burden PCS imposes on hospitals. This diversity in clinical presentation illustrates the diagnostic complexity of PCS and reinforces the need for comprehensive and systematic clinical evaluation (21, 22).

Respiratory diagnostics such as whole-body plethysmography and CO diffusion testing were frequently used. Extensive application of thoracic CT, MRI, EEG, and lumbar puncture further reflects the multi-organ complexity of PCS. These interventions suggest that clinicians routinely pursue broad differential diagnoses to assess unexplained respiratory, neurological, and systemic complaints. Given the lack of definitive biomarkers or confirmatory tests, PCS remains a diagnosis of exclusion (23, 24). Thus, future studies should aim to identify specific diagnostic markers or imaging signatures that can support early recognition, stratification, and tailored management of PCS.

Notably, care dependency assessments were documented in a considerable proportion of cases, suggesting that PCS can correlate with a significant loss of function and autonomy in a subset of patients. The need for formal evaluation of care requirements reflects the real-world burden not only on patients but also on families, caregivers, and social support systems—a factor that warrants consideration in future healthcare planning and resource allocation (25).

With nearly €67.9 million direct inpatient costs PCS represents a notable financial strain on the healthcare system. These figures varied widely depending on case complexity and resource intensity. In addition to direct medical costs, PCS is associated with substantial indirect economic consequences, including work absenteeism, reduced productivity, and prolonged disability. Previous estimates place the indirect financial burden in Germany at over €3.4 billion (26). These findings underscore the urgent need for healthcare policymakers, insurers, and public health stakeholders to develop coordinated response strategies. Sustainable financing models, investment in multidisciplinary care infrastructure, and support for return-to-work programs will be essential to mitigate both the clinical and economic impact of PCS. The transferability of the reported cost estimates to other healthcare systems should be interpreted with caution. The German DRG-based reimbursement system is characterized by standardized flat-rate payments that reflect average resource use rather than actual expenditure at the individual hospital level. As a result, cost estimates may differ in countries with alternative financing models, such as fee-for-service systems, global hospital budgets, or mixed public–private reimbursement structures. Nevertheless, the observed magnitude of inpatient resource utilization highlights that PCS imposes a substantial economic burden across healthcare systems, irrespective of the specific reimbursement framework. While absolute cost figures may not be directly comparable across countries, the relative intensity of diagnostic procedures, prolonged hospital stays in a subset of patients, and sustained inpatient utilization suggest that PCS represents a relevant cost driver in diverse health system contexts. Healthcare systems relying on fee-for-service reimbursement or global hospital budgets may experience different absolute cost estimates; however, the observed intensity of inpatient diagnostics and prolonged hospitalization in a subset of patients suggests comparable resource implications across systems.

The sustained number of PCS-related hospitalizations and the broad range of diagnostic procedures underscore that PCS represents a structural challenge for hospital systems rather than a transient post-pandemic phenomenon. The frequent use of respiratory and neurological diagnostics, combined with prolonged lengths of stay in a subset of patients, suggests that current inpatient care pathways may not be optimally adapted to the needs of PCS patients. Strengthening outpatient specialized PCS clinics, interdisciplinary rehabilitation programs, and standardized diagnostic pathways may reduce unnecessary hospital admissions and improve continuity of care.

This study has several limitations that should be considered when interpreting the findings. First, the analysis is based on secondary administrative data from the InEK database, which is primarily designed for hospital reimbursement rather than epidemiological research. Since hospital billing data are primarily intended for financial and operational purposes, clinical accuracy may be affected by variations in coding practices. The accuracy of PCS diagnoses depends on proper documentation and ICD-10 coding by hospital staff, introducing a potential risk of misclassification, underreporting, or overcoding. Additionally, PCS remains a relatively new diagnosis, and its clinical definition and diagnostic criteria are still evolving, which may have led to heterogeneous coding across different hospitals. Financial and administrative incentives within DRG-based reimbursement systems thus, may influence diagnostic coding practices, potentially affecting PCS case identification.

Second, this study only includes inpatient cases, meaning that individuals who were diagnosed and treated in outpatient settings were not captured. Since many patients with PCS are managed in primary care, specialized outpatient clinics, or through rehabilitation programs, this exclusion leads to selection bias, overrepresenting more severe cases requiring hospitalization. Consequently, the true burden of PCS in the general population may be underestimated, as milder cases and those managed without hospitalization are not included in the dataset. It is worth noting that in Germany, 248,104 patients received outpatient treatment in the fourth quarter of 2023, according to data from the Zentralinstitut für die kassenärztliche Versorgung (Zi). These figures are based on nationwide pseudonymized billing data from statutory health insurance physicians, compiled across health insurance providers in accordance with § 295 of the German Social Code Book V (SGB V) (27). Third, patient-level characteristics and clinical details such as symptom severity, laboratory values, or imaging findings are not included in the dataset. The analysis does not account for individual risk factors such as pre-existing comorbidities, lifestyle factors, vaccination status, or prior COVID-19 severity, which could significantly influence hospitalization risk and outcomes. Additionally, socioeconomic variables, such as employment status, income, or access to specialized care, are not captured, limiting the ability to assess potential disparities in healthcare access and treatment patterns.

Further, while this study specifically aimed to estimate direct inpatient costs using G-DRG reimbursement data, it does not capture indirect costs or outpatient care expenses. As a result, the economic burden of PCS is likely underestimated, since costs associated with primary care visits, rehabilitation, mental health services, long-term disability, and productivity loss are not included.