Association of polydoctoring and mortality among persons over 85 years with multimorbidity: a prospective cohort study in Japan.

Background: Polydoctoring can increase the risk of care fragmentation among patients with multimorbidity, but its impact on health outcomes remains unclear.

Aim: To determine the effects of polydoctoring, as measured by the regularly visited facilities (RVF) indicator, on patient outcomes among older individuals with multimorbidity.

Design & Setting: Data from the ongoing prospective cohort study, Kawasaki Aging and Wellbeing Project (KAWP), was utilised in this study. Among the 1026 KAWP participants aged 85-89 years, those with two or more chronic conditions were enrolled in this study.

Method: Care fragmentation and polydoctoring was evaluated using the RVF, which is a new indicator that measures the number of medical facilities consistently involved in a patient's care. Based on RVF, mortality was analysed using the Cox proportional hazards model, with adjustments for age, sex, frailty, and number of comorbidities.

Results: A significant reduction in mortality rates was observed in participants with an RVF of ≥3 and 2-4 comorbidities (hazard ratio [HR] 0.43, 95% confidence interval [CI] = 0.18 to 0.99, value = 0.048). However, no significant difference in mortality based on RVF was observed for those with ≥5 comorbidities. Notably, individuals with ≥5 comorbidities and an RVF of 0 had a significantly higher HR for death (HR 2.68, 95% CI = 1.05 to 6.84, value = 0.039).

Conclusion: In older patients with multimorbidity, polydoctoring may reduce mortality in patients with ≤4 coexisting conditions, but it does not significantly impact mortality in those with ≥5 conditions. These findings provide insights for healthcare decision making in managing older patients with multimorbidity.