Metabolic control and its variability are major risk factors for microalbuminuria in children with type 1 diabetes

Abstract

Introduction: To assess in a prospective study the course and the predictors of microalbuminuria in children and adolescents with type 1 diabetes.

Material and methods: 438 children and adolescents who developed diabetes in the years 1985–2004 were followed for 9.2 ± 3.4 years from the diagnosis. Microalbuminuria was assessed on the basis of timed overnight urine collections performed once per year. Variability of glycated haemoglobin was expressed as a coefficient of variation (%) calculated by dividing standard deviation (adjusted for the number of measurements) by mean of HbA1c.

Results: Microalbuminuria was noted in 99 patients (22.6%) after 8.27 ± 3.3 years of diabetes. In 29 individuals (6.6%), microalbuminuria was persistent. The prevalence of microalbuminuria was not dependent on the period of diabetes diagnosis. During followup, 17 (58.6%) patients with persistent MA reverted to normoalbuminuria. Children without any episodes of microalbuminuria had significantly lower HbA1c variability (8.44%; 95% CI 7.81–9.08%) than those with one (10.28% 95% CI 9.10–11.47%; p = 0.007). The difference of HbA1c variability between patients with and without microalbuminuria persisted after correction by mean HbA1c (p = 0.04). Risk factors for ever developing microalbuminuria during the observation period in multivariate analysis included: mean HbA1c (HR [95% CI]: 1.17 [1.00–1.37; p = 0.05]) and its variability (1.04 [1.00–1.07]; p = 0.05), insulin dose (HR per 0.1 unit*kg- 1*day–1: 0.87 [0.79–0.96]; p = 0.005), presence of arterial hypertension (1.63 [1.07–2.49]; p = 0.02), and age at onset of diabetes (1.15 [1.08–1.21]; p < 0.0001).

Conclusions: Children who develop microalbuminuria are characterised by poorer and more variable metabolic control, hinting at the importance of interventions aimed at both improvement and stabilisation of HbA1c levels. (Endokrynol Pol 2014; 65 (2): 83–89)