Incidence of Idiopathic Cardiomyopathy in Type 2 Diabetes Patients: Age, Sex, and Urbanization status stratified Analysis

Abstract

Background There are limited data regarding epidemiology of diabetes and idiopathic cardiomyopathy. We investigated the overall and age, sex, and urbanization-specific incidence and relative hazard of idiopathic cardiomyopathy in association with type 2 diabetes in Taiwan. Methods A total of 474,268 type 2 diabetes patients were identified from ambulatory care and inpatient claims in 2007–2009 from Taiwan’s National Health Insurance (NHI) database, and 474,266 age-, sex- and diagnosis date-matched controls were randomly selected from the registry of NHI beneficiaries. All study subjects were linked to ambulatory care and inpatient claims (up to the end of 2016) to identify possible diagnosis of idiopathic cardiomyopathy. The person-year approach with Poisson assumption was used to estimate the incidence; and Cox proportional hazard regression model with Fine and Gray’s method was used to estimate the relative hazards of idiopathic cardiomyopathy in relation to type 2 diabetes. Results The overall incidence of idiopathic cardiomyopathy for men and women patients, respectively, was 4.26 and 3.34/10,000 person-years, which were higher than the corresponding men and women controls (2.40 and 1.69 per 10,000 person-years). Compared with control group, type 2 diabetes patients were significantly associated with an increased hazard of idiopathic cardiomyopathy (adjusted hazard ratio [aHR] 1.39, 95% confidence interval [CI] 1.28–1.51] in all age and sex stratifications except in those aged > 64 years. Type 2 diabetes aged < 45 years confronted the greatest increase in hazard of idiopathic cardiomyopathy, with an aHR of 2.36 (95% CI 1.68–3.32) and 3.72 (95% CI 1.86–7.44) for men and women, respectively. Patients living in rural areas tended to have higher HRs of idiopathic cardiomyopathy. Conclusions In Taiwan, diabetes increased the risk of idiopathic cardiomyopathy in both sexes as well as in all age groups except in those > 64 years. Younger patients and those living in rural areas were especially vulnerable to have higher HRs of idiopathic cardiomyopathy.