Natural course of untreated microalbuminuria in children and adolescents with type 1 diabetes and the importance of diabetes duration and immigrant status: longitudinal analysis from the prospective nationwide German and Austrian diabetes survey DPV

Objective: To identify risk factors for the development and progression of untreated persistent microalbuminuria in children and adolescents with type 1 diabetes. Design and methods: A total number of 683 children and adolescents with type 1 diabetes recruited from the prospective nationwide German and Austrian diabetes survey (DPV) were included in the analysis. Inclusion criteria were onset of type 1 diabetes under the age of 11 years, diabetes duration of more than 1 year and continuous follow-up over 5 years with at least two documented urine analyses per year. Subjects treated with angiotensin-converting enzyme inhibitors were excluded. Risk factors such as sex, body mass index SDS, diabetes duration, HbA1c, total cholesterol, HDL-cholesterol, LDL-cholesterol, systolic and diastolic blood pressure, and immigrant status were analysed by logistic regression. Results: At baseline (age 10.5 +/- 0.1 years, diabetes duration 4.6 +/- 2.4 years and HbA1c 7.4 +/- 1.1%), 75.6% of children had normoalbuminuria, 15.7% had intermittent microalbuminuria, 8.6% had persistent microalbuminuria and 0.1% had macroalbuminuria. After a follow-up of 5 years, 59.4% of adolescents continued to have normoalbuminuria, 18.4% had progression, 15.2% had regression of microalbuminuria, and in 6.9% of the subjects, microalbuminuria remained unchanged. We found significant associations between persistent microalbuminuria at baseline and during each year of follow-up (P < 0.0001). Logistic regression analysis identified diabetes duration and immigrant status as significant factors for microalbuminuria (P = 0.009 and P = 0.009). Conclusions: The survey in a real-world setting shows that diabetes duration and immigrant status are risk factors for the development and progression of untreated microalbuminuria in children and adolescents with type 1 diabetes.