Abstract
INTRODUCTION: Multimorbidity, the co-occurrence of 2 or more disorders in a patient, can complicate treatment planning and affect health outcomes. Improvements in prevention and management strategies for patients with 3 or more or more co-occurring chronic diseases requires an understanding of the epidemiology of common 3-way disease patterns and their interactions. Our study aimed to describe these common 3-way disease patterns and examine the factors associated with the co-occurrence of 3 or more diseases in elderly Japanese patients. METHODS: We included all Japanese citizens aged 75 or older living in Tokyo who used medical care between September 2013 and August 2014 (N = 1,311,116) in our analysis. The 15 most common 3-way patterns of 22 target diseases according to sex and age were identified from among all possible combinations by using an anonymized medical claims database. We examined the associations of sociodemographic characteristics and health care use with the presence of 1 or 2 co-occurring diseases and 3 or more co-occurring diseases by using multinomial logistic regression. RESULTS: Approximately 65% of patients had 3 or more co-occurring diseases. The most common 3-way pattern was hypertension, coronary heart disease, and peptic ulcer disease in men (12.4%) and hypertension, dyslipidemia, and peptic ulcer disease in women (12.8%). The prevalence of 3 or more diseases was positively associated with men, patients aged 85 to 90, the use of home medical care services, the number of outpatient facilities visited, and hospital admissions. CONCLUSION: The common 3-way disease patterns and multimorbidity factors identified in our study may facilitate the recognition of high-risk patients and support the development of clinical guidelines for multimorbidity.