Association between non-communicable diseases and work productivity and health-related quality of life among Japanese workers: a cross-sectional study using a claims database and survey data.

OBJECTIVES: To assess the impact of non-communicable diseases (NCDs) by number and pattern on productivity loss costs (PLCs) and health-related quality of life (HRQoL) in a large working-age population in Japan. DESIGN: Cross-sectional analysis of linked claims-survey data with sex-stratified multivariable regression. SETTING: Employment-Based Health Insurance Associations in Japan. Administrative claims using International Classification of Diseases, Tenth Revision codes were linked to an online questionnaire (November 2022). PARTICIPANTS: Insured workers and families aged 18-65 years who completed the survey (n=18 236; mean age 48.7 years; 66.2% men). PRIMARY AND SECONDARY OUTCOME MEASURES: Primary: PLC, estimated from the Work Productivity and Activity Impairment instrument using the Human Capital Method (annual US$). SECONDARY: HRQoL measured using the EuroQoL 5-Dimension 5-Level index. Exposures were NCD categories, multimorbidity counts and high-impact disease combinations. Models adjusted for sex, age and the number of other conditions. RESULTS: Multimorbidity (≥2 conditions) was present in 58.4% (56.3% men; 62.5% women); 29.3% had ≥5 conditions. Women had higher NCD prevalence (76.9% vs 70.0%), higher median PLC (US$3683 vs US$117) and lower median HRQoL (0.89 vs 1.00) than men. In adjusted analyses, neuropsychiatric conditions were associated with higher PLC in both sexes (men: US$2393 (95% CI 1966 to 2820); women: US$2097 (US$1442 to US$2751)). Musculoskeletal disorders were statistically significant in men but not in women (US$809 (US$381 to US$1236)), whereas genitourinary disorders were statistically significant in women but not in men (US$701 (US$121 to US$1282)). Neuropsychiatric disorders were associated with lower HRQoL in both sexes (men: -0.040 (-0.045 to -0.034); women: -0.044 (-0.053 to -0.035)); musculoskeletal disorders showed similar decrements (men: -0.031 (-0.037 to -0.025); women: -0.040 (-0.049 to -0.031)). Combinations involving sleep and neuropsychiatric disorders produced the highest PLC (eg, depressive episode and sleep disorder: men: US$5219.9 (US$3646.4 to US$6793.4); women: US$5858.5 (US$2634.4 to US$9082.5)). Each additional condition was independently associated with higher PLC and lower HRQoL. CONCLUSIONS: In this cross-sectional study of Japanese workers, specific combinations of chronic conditions, particularly neuropsychiatric conditions co-occurring with sleep disorders and musculoskeletal disorders, were associated with greater productivity loss and lower HRQoL than predicted by the number of co-occurring diseases alone. These findings suggest that workplace health strategies addressing high-impact disease combinations may warrant further investigation in longitudinal studies.