Impact of long COVID on health-related quality-of-life among Japanese adults: findings of CARE Japan study.

Publication date: Jun 06, 2026

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. 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. 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. Long COVID patients had reduced HRQoL. Female gender, young-age, thin BMI or pre-existing psychological disorders were associated with lower HRQoL.

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