BABA, T., MURABAYASHI, S., TOMIYAMA, T. and TAKEBE, K. Uncontrolled Hypertension is Associated with a Rapid Progression of Nephropathy in Type 2 Diabetic Patients with Proteinuria and Preserved Renal Function. Tohoku J. Exp. Med., 1990, 161 (4), 311-318-The relationship between blood pressure and progression of nephropathy was studied the mean follow-up period of 32.6± 17.9 (S.D.) months in 20 Type 2 (non-insulin-dependent) diabetic patients with clinical nephropathy (proteinuria >0.5g/day) and preserved renal function (serum creatinine level <150μmol/liter). Fifteen hypertensive patients under antihypertensive treatment were divided into 2 groups: those with the mean diastolic blood pressure ≥90mmHg and/or the mean systolic blood pressure ≥150mmHg during the follow-up period were designated as Group A (n=6) and the remainders as Group B (n=9). Five normotensive patients without any antihypertensive treatment throughout the follow-up period served as a control group (Grgoup C). The decline rate in GFR was significantly greater (p<0.05) in Group A (1.15±0.39 (S.E.) ml/min/month) than those in Groups B (0.33±0.08ml/min/month) and C (0.40±0.09ml/min/month), respectively. The decline rate in GFR showed significant positive correlations both with systolic (r_s=0.553, p<0.05) and diastolic (r_s=0.493, p<0.05) blood pressures in the 15 hypertensive patients. The age, initial glomerular filtration rate, duration of diabetes and mean HbA_1C level during the observation period were comparable in Groups A, B and C, respectively. The results indicate that an uncontrolled hypertension is associated with a rapid progression of kidney impairment in Type 2 diabetic patients with overt nephropathy, as has been suggested in Type 1 (insulin-dependent) diabetic patients.