Systolic blood pressure relates to the rate of progression of albuminuria in NIDDM

Summary We prospectively followed a cohort of 278 non-insulin-dependent (NIDDM) patients for a 6-year period, intending to estimate the rate of increase of albuminuria and to identify clinical variables that influence this increase. At baseline, normo-albuminuria (N) was seen in 74%, microalbuminuria (M) in 19% and 7% presented with proteinuria (P). A total of 80 patients died; they were older (p<0.001) and had higher albumin excretion both at baseline and as an average during follow-up (p<0.01). At baseline, patients with proteinuria had higher blood pressures (systolic and diastolic), whereas there was no difference between patients with normo- and microalbuminuria. Glycaemic control was increasingly poor throughout the three groups. At follow-up, an average relative rate of increase of albuminuria (slope) of 17% per year was seen both for patients with complete 6 years, follow-up (n=135) and patients with at least 4 years follow-up (n=178). Slope correlated significantly with systolic blood pressure (r=0.26 and 0.29) in both groups, diastolic blood pressure only in the 4-year group (r=0.22) and average albuminuria in both (r=0.31 and 0.24). By multiple regression analyses systolic blood pressure and average albuminuria remained with significant influence on slope. Progression was defined as an increase in the category (e. g. normoto microalbuminuria) as well as an increase of more than 20% in albumin excretion, and was seen in 46 patients with at least 4 years' follow-up. Progressors (patients demonstrating progression) had higher systolic blood pressure (165 mm Hg±20 vs 156±17) and poorer glycaemic control (HbA_1C: 8.2%±1.5 vs 7.7±1.3) p<0.05, as well as a higher level of albuminuria at baseline. The present study points to systolic blood pressure and general level of albuminuria as factors determining the rate of progression of albuminuria. However, only a modest fraction of the variation between subjects was explained by these variables.Abbreviations IDDM insulin-dependent diabetes mellitus - NIDDM non-insulin-dependent diabetes mellitus - N normal urinary albumin excretion - M microalbuminuria - P proteinuria - Slope relative rate of increase - UAC urinary albumin concentration - UAE urinary albumin excretion rate