Remission to normoalbuminuria during multifactorial treatment preserves kidney function in patients with type 2 diabetes and microalbuminuria

Background. Intervention studies in microalbuminuric type 2 diabetic patients have demonstrated that it is possible to avoid progression to overt diabetic nephropathy and even to achieve regression to normoalbuminuria. However, the long-term impact of stabilization/regression in albuminuria on decline in glomerular filtration rate (GFR) has not been established. Methods. 151 patients with type 2 diabetes and microalbuminuria at baseline in whom GFR was measured at least three times during 7.8 years of follow-up were divided into three groups according to the level of albuminuria during follow-up. Overt nephropathy was diagnosed as a urinary albumin excretion rate (AER) >300 mg/24 h and remission to normoalbuminuria was defined as an AER <30 mg/24 h at the last examination. Results. During follow-up, 46 patients achieved remission to normoalbuminuria, 58 remained microalbuminuric and 47 patients progressed to overt nephropathy. The mean (± SE) yearly decline in GFR was lowest (2.3 ± 0.4 ml/min/year) in patients who obtained remission, in comparison with patients remaining microalbuminuric, in whom the decline was 3.7 ± 0.4 ml/min/year, and patients progressing to overt nephropathy, who had a decline in GFR of 5.4 ± 0.5 ml/min/year (ANOVA, P<0.001). Start of antihypertensive treatment during follow-up was strongly associated with remission to normoalbuminuria [odds ratio: 2.32; 95% confidence interval (CI): 1.09-4.93] whereas a decrease in HbA_1c by 1% increased the probability for remission (odds ratio: 1.48; 95% CI: 1.11-1.97). Conclusions. Remission to normoalbuminuria was associated with a decreased GFR decline during 7.8 years of follow-up in type 2 diabetic patients with microalbuminuria. Antihypertensive therapy and improved glycaemic control were independent predictors for remission.