Renal function changes in hypertensive patients with non-insulin- dependent diabetes mellitus

A group of 146 patients with non-insulin- dependent diabetes mellitus (NIDDM) was studied. They were divided into two groups of 73 age and sex matched patients, according to the presence or absence of hypertension. We recorded the presence of macrovascular and microvascular complications of NIDDM, family history, body mass index (BMI), glycemic control and lipidic profile. Renal parameters included plasma creatinine, urinary albumin excretion rate (UAER), glomerular filtration rate (GFR), effective renal plasma flow (ERPF) and filtration fraction. Hypertensive patients had a higher BMI (30 +/- 4.8 kg/m2 vs. 27.6 +/- 4.4 kg/m2, P < 0.005), total cholesterol (6.34 +/- 1.47 mmol/l vs. 5.72 +/- 1.14 mmol/liter, P < 0.01), creatinine (91.1 +/- 25.6 mumol/liter vs. 81.3 +/- 20.3 mumol/liter, P < 0.05) and UAER [63.7 (range 1 to 5160) mg/24 hr vs. 27.3 (3 to 5500) mg/24 hr, P < 0.001]. GFR was lower in the group with hypertension (113 +/- 35 ml.min-1.1.73 m-2 vs. 127 +/- 29 ml.min-1.1.73 m-2, P < 0.05), but there were no differences in ERPF. The difference in GFR was only apparent in patients without established diabetic nephropathy. Hypertensive patients had higher frequency of ischemic heart disease (18% vs. 6%, P < 0.05) and diabetic nephropathy (62% vs. 38%, P < 0.005). We conclude hypertensive NIDDM patients, when compared with normotensive NIDDM patients, are more obese, hypercholesterolemic and have a higher frequency of ischemic heart disease and diabetic nephropathy. Hypertensive NIDDM patients have a worse renal function than normotensives before clinical proteinuria appears. The deterioration of GFR in hypertensive NIDDM patients possibly has an important influence on the progression of diabetic nephropathy.