GLOMERULAR-FILTRATION RATE AND KIDNEY SIZE AFTER 6 YEARS DISEASE DURATION IN NON-INSULIN-DEPENDENT DIABETIC SUBJECTS

The objective of the present study was to estimate how glomerular filt ration rate and kidney size change after six years of diabetes in subj ects with non-insulin-dependent disease. it is a population-based pros pective study of a cohort of non-insulin diabetic patients (n = 150) d iagnosed 1985-1988. The baseline studies utilized a non-diabetic contr ol group, whose basic characteristics were equal to the study group. T he setting was a primary health care center in an urban area. Main out come measures were the glomerular filtration rate and its relation to renal area, mean blood pressure, hemoglobin Ale, serum insulin and cho lesterol. Seventeen patients had died and 109 were eligible for evalua tion at follow-up. The mean (standard deviation) of the glomerular fil tration rate (ml/min/1.73 m(2)) remained elevated at follow-up, 118 (2 8), just as it was at baseline, 118 (28) in the diabetic subjects comp ared to matched non-diabetic subjects, 103 (24) (p = 0.0000). Kidney s ize (cm(2)) was larger in diabetic subjects at follow-up, 114 (19) tha n at baseline, 109 (18) (p = 0.0000) and in non-diabetic subjects 98 ( 14) (p < 0.0000). This resulted in a decline in glomerular filtration rate per unit renal area in the diabetic subjects at follow-up, 1.0 (0 .23) compared to at baseline, 1.09 (0.23) (p = 0.002) and to non-diabe tic subjects, 1.07 (0.23). The renal area at baseline was directly and significantly related to the glomerular filtration rate at follow-up (p < 0.001), The relation of baseline serum cholesterol, hemoglobin Al e and mean arterial blood pressure to the glomerular filtration rate a t follow-up was inverse and reached significance in those diabetic sub jects having had high filtration rates at baseline but displaying a fa ster decline than on average i. e. in those patients who were at incre ased risk of renal insufficiency. We conclude that after the first six years of non-insulin-dependent diabetes the glomerular filtration rat e remains high, Kidney size increases further from the attained increa se at diagnosis and is an important determinant of continuing hyperfil tratian. The deleterious effect of serum cholesterol and high blood gl ucose on the glomerular filtration rate at this early stage of diabeti c kidney disease is suggestive.