Effect of multimorbidity patterns on the decline in health-related quality of life: a nationwide prospective cohort study in Japan

OBJECTIVES: Longitudinal studies, which consider multimorbidity patterns, are useful for better clarifying the effect of multimorbidity on health-related quality of life (HRQoL) and for identifying the target population with poorer clinical outcomes among patients with multimorbidity. This study aimed to examine the effects of different multimorbidity patterns on the decline in HRQoL. DESIGN: Nationwide prospective cohort study. SETTING: Japanese adult residents. PARTICIPANTS: Residents aged ≥50 years selected by the quota sampling method. PRIMARY OUTCOME MEASURE: Clinically relevant decline in HRQoL was defined as a 0.50 SD (5-point) decrease in the 36-Item Short Form Health Survey (SF-36) component summary scores for 1 year. RESULTS: In total, 1211 participants completed the follow-up survey. Among the multimorbidity patterns identified using confirmatory factor analysis, multivariable logistic regression analyses revealed that high cardiovascular/renal/metabolic and malignant/digestive/urologic pattern scores were significantly associated with the clinically relevant decline in SF-36 physical component summary score (adjusted OR (aOR)=1.25, 95% CI: 1.08 to 1.44 and aOR=1.28, 95% CI: 1.04 to 1.58, respectively). High cardiovascular/renal/metabolic pattern score was also significantly associated with the clinically relevant decline in SF-36 role/social component summary score (aOR=1.23, 95% CI: 1.06 to 1.42). CONCLUSIONS: Our study revealed that multimorbidity patterns have different effects on the clinically relevant decline in HRQoL for 1 year. These findings can be useful in identifying populations at high risk and with poor clinical outcomes among patients with chronic diseases and multimorbidity for efficient resource allocation.