Objectives: This study aimed to comprehensively assess the implications of long COVID on the health-related quality-of-life (HRQoL) among Japanese adults and to identify its associated factors.
Methods: This study used prospective cohort data from the CARE Japan Study between January 2022 and January 2023. The outcome of this study was HRQoL, which was measured using SF-12 questionnaire. Self-reported long COVID was the primary independent variable. We fitted adjusted beta regression models to calculate beta regression coefficients with 95% confidence intervals (CI) and average marginal effects (AME) to explore the determinants of HRQoL. We also performed latent class analysis (LCA) to identify unobserved patterns of long COVID symptoms.
Results: Final sample size was 1,285. Compared to the participants with no long COVID, the HRQoL among long COVID patients (β: -0.25; 95% CI: -0.36 to -0.14; AME: -0.036) was significantly lower. The effect of long COVID on HRQoL was the most pronounced among the respondents with pre-existing lung diseases (β: -0.72; 95% CI: -1.29 to -0.16; AME: -0.114). LCA identified three subgroups of long COVID patients - class 1, 2, and 3. Compared to the participants with no long COVID, participants belonged to class 1 (β: -0.47; 95% CI: -0.57 to -0.36; AME: -0.065), class 2 (β: -0.48; 95% CI: -0.60 to -0.35; AME: -0.066), and class 3 (β: -0.93; 95% CI: -1.06 to -0.79; AME: -0.148) had poorer HRQoL.
Conclusions: Long COVID patients had reduced HRQoL. Female gender, young-age, thin BMI or pre-existing psychological disorders were associated with lower HRQoL.
Keywords: Health-related quality-of-life; Japanese adult population; Latent class analysis; Long COVID symptoms; Post-COVID conditions; Post-COVID-19 syndrome; Post-acute sequelae of COVID-19; Psychological disorder; SARS-CoV-2 infection.
Now, after five years of COVID-19 pandemic about 779 million of COVID-19 cases were reported, as of October 2025. Survivors of COVID − 19 often report complex, multisystemic, persistent or relapsing symptoms for weeks, months, or even years after the initial infection of COVID-19. When the symptoms are persistent or relapsing even after 12 weeks of initial acute infection, it is termed as long COVID. Due to high prevalence, heterogeneous nature, lack of clear diagnostic markers, prolonged, and obscure recovery process, long COVD is posing challenges on individuals’ lives, public healthcare systems, and workforce. Increasing evidence is suggesting that long COVID is impairing functional and cognitive capacity of the patients resulting poor health-related quality-of-life. Longitudinal studies on health-related quality-of-life among COVID-19 survivors with long follow up period is scarce in Japan. Therefore, in our study we measured the impact of COVID-19 infection on the health-related quality-of-life among Japanese adults with follow up period of 1 year. We found that, long COVID patients had lower health-related quality-of-life compared to the COVID-19 survivors without long COVID. The presence of minimal long COVID symptoms lowered the health-related quality-of-life. For COVID-19 cases with lung disease as a comorbid condition, the risk of reduced quality of life remains high even after recovery. Findings of this research will enhance the understanding of the implications of long COVD on individual’s lives and will underscore the need of coordinated approach for long-term treatment, care, and prevention of long COVID through policies, interventions, and integrated health care system.
© 2026. The Author(s).