MICROALBUMINURIA AS A PREDICTOR OF A DROP IN GLOMERULAR-FILTRATION RATE IN SUBJECTS WITH NON-INSULIN-DEPENDENT DIABETES-MELLITUS AND HYPERTENSION

Hypertension and non-insulin-dependent diabetes mellitus (NIDDM) are t wo major risk factors for end-stage renal failure. The value of microa lbuminuria (urinary albumin excretion [UAE]: 30-300 mg/24 h) as an ind icator of the glomerular filtration rate (GFR) is not known in these p atients. Methods: The relationships between microalbuminuria and GFR i n subjects with NIDDM and hypertension were studied cross-sectionally (Study I) and longitudinally (Study II). Results: In study I, 205 NIDD M subjects with hypertension (151 with normoalbuminuria [UAE <30 mg/24 h] and 54 with microalbuminuria) were studied. The GFR of subjects wi th normoalbuminuria (97 +/- 30 ml/min) (mean +/- SD), and microalbumin uria (97 +/- 27 ml/min; NS) were similar. Study II examined 51 of the subjects with normoalbuminuria and 21 with microalbuminuria 22 months (range 13-57) later. The GFR of subjects with microalbuminuria (-10 +/ - 19 ml/min) declined more than in those with normoalbuminuria (+4 +/- 17 ml/min; Student's t-test: p = 0.0022). The predictive value of mic roalbuminuria for a drop in GFR was independent of the antihypertensiv e treatment used, the follow-up time, or changes in UAE, The only vari able linked to GFR loss in subjects with microalbuminuria was an incre ase in diastolic blood pressure (p = 0.0298). Conclusion: Microalbumin uria is a risk factor for a drop in GRF in NIDDM subjects with hyperte nsion, and a reduction in blood pressure is the only effective way to prevent a loss of GFR in subjects with microalbuminuria.