RELATIONSHIP BETWEEN EARLY METABOLIC CONTROL AND THE DEVELOPMENT OF MICROALBUMINURIA - A LONGITUDINAL-STUDY IN CHILDREN WITH TYPE-1 (INSULIN-DEPENDENT) DIABETES-MELLITUS

The cumulative incidence of microalbuminuria from onset up to 15 years of Type 1 (insulin-dependent) diabetes mellitus and the relative impo rtance of age, duration, blood pressure and metabolic control for subs equent microalbuminuria was studied in 156 children. Urinary albumin e xcretion and HbA1c were followed at 3-month intervals from onset and s ystolic and diastolic blood pressure at the same interval from 5 years of diabetes. Persistent microalbuminuria over 20 mug/min developed in 17 children. The cumulative incidence by duration was 24.2% at 15 yea rs of diabetes. Eleven patients developed microalbuminuria after more than 5 years. Among these, first 5-year mean HbA1c was 8.4 +/- 1.3% vs 7.2 +/- 1.1% in normoalbuminuric children (p < 0.001). The crude rela tive risk of developing microalbuminuria with a first 5-year mean HbA1 c greater than 7.5% was 4.49 (95 % confidence interval 1.13-17.84). Th e age- and duration-adjusted relative risk was 3.51% (0.90-14.42). The year before transition to microalbuminuria neither mean HbA1c nor yea rly mean blood pressures, sex or age at onset of diabetes differed fro m normoalbuminuric children at the same diabetes duration. Age and dur ation were higher (p = 0.04). The relative importance of early vs late r hyperglycaemia, yearly blood pressures, age, age at onset and durati on of diabetes for increased albumin excretion rate after more than 5 years, was shown in a multiple regression analysis where the first 5-y ear mean HbA1c was the only independent predictor (p = 0.02). Six pati ents had an onset of microalbuminuria before 5 years of diabetes. In t his group age, age at onset and yearly mean HbA1c levels did not diffe r from normoalbuminuric children at the same duration. We conclude tha t one-fourth of diabetic youth under the age of 21 years develop micro albuminuria within 14 years of diagnosis. Some patients have an early onset of microalbuminuria, not necessarily related to hyperglycaemia, while in later onset cases early hyperglycaemia is strongly related to subsequent microalbuminuria.