Risk of future microvascular and macrovascular disease in people with Type 1 diabetes of very long duration: a national study with 10-year follow-up

Aims To describe factors associated with prevalence or absence of microvascular and macrovascular complications in people with Type 1 diabetes of very long duration and to investigate the risk factors associated with the incidence of such complications. Methods We included individuals with Type 1 diabetes who had been entered in the Swedish National Diabetes Register between 2002 and 2004 (n = 18 450). First, risk factor distribution in people with diabetes duration of ≥ 50 years was compared between people with and without complications. Second, the incidence of complications during a 10‐year follow‐up period was studied in all individuals who had no complications at baseline. Results Among people with a diabetes duration of ≥ 50 years (n = 1023), 453 (44%) had macrovascular disease, 534 (52%) had microvascular disease and 319 (31%) did not have either of the diagnoses. Factors that differed significantly between people with and without macrovascular disease were gender, age, HbA1c, BMI, LDL cholesterol, HDL cholesterol, triglycerides, systolic blood pressure, albuminuria, antihypertensive medication and lipid‐lowering medication. The same factors differed significantly between people with and without microvascular disease, with the exception of gender and HDL cholesterol. During the follow‐up period, 6.1% of the study cohort were diagnosed with macrovascular disease and 19.6% with microvascular disease. Incidence of macrovascular disease was significantly associated with HbA1c levels. Hazard ratios decreased with longer diabetes duration. Conclusions People with Type 1 diabetes who have survived ≥ 50 years without complications are significantly younger, and have significantly lower HbA1c levels, BMI and triglyceride levels than survivors with complications. HbA1c level is a predictor of macrovascular disease, independently of diabetes duration.
What's new? Previous studies in long‐term survivors of Type 1 diabetes have mainly been cross‐sectional, relying on self‐reported data, and the results have been inconsistent.This register‐based study of 18 450 people with Type 1 diabetes shows that those who have survived ≥ 50 years without complications are significantly younger and have significantly lower HbA1c levels, BMI and triglyceride levels than survivors with complications.HbA1c is a predictor of macrovascular disease, independently of diabetes duration, even after 50 years’ duration of Type 1 diabetes.It is important to identify factors that may protect individuals with Type 1 diabetes from major complications.