Objective To explore the comorbidity patterns of chronic diseases and their associated factors in the elderly population aged 60 and above in China.

Methods Based on the data from the 2018 China Health and Retirement Longitudinal Study (CHARLS), the Apriori algorithm in R4.0.4 software was used to extract frequent itemsets and construct an association rule model between chronic diseases and their associated factors, targeting the information on 14 chronic diseases in people aged 60 and above in the database.

Results Among the 13 206 participants, 3 691 cases (27.90%) suffered from at least one chronic disease, while 6 217 cases (47.08%) suffered from two or more chronic diseases. Analysis of association rules showed that the most common comorbidity patterns included heart disease and hypertension, dyslipidemia and hypertension, diabetes and hypertension, as well as "heart disease, arthritis→high blood pressure" "high blood pressure, stomach disease→arthritis" "dyslipidemia, arthritis→hypertension", with support degrees of 8.93%, 8.29%, 5.44%, 3.82%, 3.71% and 3.22%, and confidence degrees of 55.15%, 59.64%, 60.13%, 53.67%, 51.58% and 60.11% respectively. Irregular sleep patterns, urban living backgrounds, and high social participation were strongly associated with hypertension; while irregular sleep patterns, rural residency, and female were highly associated with arthritis.

Conclusion Given the universality of hypertension in multiple chronic disease comorbidity patterns, the prevention and screening of hypertension and its complications in the elderly population should be strengthened. For the comorbidity patterns of chronic diseases coexisting with hypertension, special attention should be paid to the daily disease screening and management of the elderly who participate in social activities in cities. At the same time, for elderly women, poor sleep quality, and rural residents, the screening and attention to the comorbidity patterns of chronic diseases with arthritis need to be strengthened.