Abstract
IMPORTANCE: Patients with type 1 diabetes (T1D) and a family history of type 2 diabetes (T2D) appear to be at a high risk of diabetes complications and other cardiovascular diseases. However, estimates of individual risks in patients in Taiwan are largely unavailable or unreliable. OBJECTIVE: To evaluate the risk of diabetes complications and major adverse cardiovascular events (MACEs) in patients with T1D with a family history of T2D. DESIGN, SETTING, AND PARTICIPANTS: A population-based cohort study used the Taiwan National Health Insurance Research Database. Participants included all individuals registered in that database on December 31, 2017, and followed up since March 1, 1995. The data were analyzed from December 6, 2018, to December 5, 2019. EXPOSURE: Patients with T1D and a family history of T2D were evaluated. MAIN OUTCOMES AND MEASURES: The prevalence and hazard ratios (HRs) of diabetes complications and other cardiovascular diseases in patients with T1D were analyzed. The MACEs were identified by diagnostic or procedural codes and heritability was formulated by the registry data of beneficiaries. RESULTS: Of 27 370 965 individuals included in the database, 11 237 (mean [SD] age, 22.7 [14.4] years; 54% were female) had T1D. The crude prevalence of T1D was 0.04%, with a female to male ratio of 1.22: 1. The adjusted HRs in individuals who had a first-degree relative with T2D were 2.61 (95% CI, 1.32-5.16) for MACEs at an age at diagnosis of less than 20 years. Adjusted HRs were 1.44 (95% CI, 1.27-1.64) for diabetic neuropathy, 1.28 (95% CI, 1.12-1.47) for retinopathy, and 1.24 (95% CI, 1.06-1.47) for neuropathy at all ages of diagnosis. CONCLUSIONS AND RELEVANCE: In this study of patients in Taiwan with T1D, having relatives with T2D was associated with an increase in the individual risks of developing diabetes complications. Patients with T1D and a family history of T2D might have more complications and require close management.