Associations of diverse diseases with work productivity among Japanese workers in the context of multimorbidity: additional analysis of a database study.

Objectives: Building on the previous descriptive study of work productivity across various diseases among Japanese workers, this additional analysis aimed to assess the associations between multimorbidity and work productivity, as well as independent associations between each disease and work productivity, accounting for coexisting diseases.

Methods: From the original study population of the secondary dataset derived from health insurance claims and online surveys, including workers aged ≥19 years who completed the Work Productivity and Activity Impairment questionnaire-General Health (WPAI-GH) in an online survey in 2021, we analyzed participants aged <65 years (n = 30 953). The association of a WPAI score >0% with diseases count and each target disease adjusted for other diseases was explored using logistic regression, and the predicted probabilities of having a score >0% for each disease were derived.

Results: The odds ratios (ORs) for having a WPAI score of >0% increased (OR > 1) per additional disease. Associated with higher odds of having a score >0% were, in males, migraine, depression, dysthymia, diarrheal disorders, and insomnia; and in females, migraine, insomnia, and atopic dermatitis. Femoral neck fracture, dysthymia, depression, migraine, and menopausal disorder in males, and migraine and ischemic heart disease in females were among the top diseases with high predicted probabilities.

Conclusions: Each incremental disease was significantly associated with impaired work productivity. After adjusting for other comorbidities, work productivity impairment was associated with psychiatric disorders and migraines. These findings underscore the importance of optimal management of preexisting conditions and prevention of comorbidities.