Cigarette smoking is associated with augmented progression of renal insufficiency in severe essential hypertension

Hypertension-associated renal disease is a major cause of end-stage renal d isease (ESRD) in the United States, but its risk factors remain incompletel y defined. Identification and correction of amendable ESRD risk factors amo ng patients with essential hypertension could reduce ESRD prevalence, Patie nts referred by their primary care physician for hypertension management to an academic nephrology clinic during calendar year 1995 were followed up p rospectively. Studied patients had no evidence of secondary hypertension, d iabetes, or primary renal disease. All were treated pharmacologically towar d a target mean blood pressure (MBP) of 100 mm Hg or less. The course of re nal function during follow-up was assessed as the slope of the reciprocal o f plasma creatinine concentration (1/P-cr) plotted against months of follow -up and as the change in calculated glomerular filtration rate (GFR) in mil liliters per minute per month. The following patient characteristics were p rospectively examined as possible predictive factors for altered renal func tion: age, sex, ethnicity, initial MBP, initial P-cr level, initial level o f urine protein excretion, and smoking status. Fifty-three patients were en rolled, and follow-up data were available for 51 patients after a mean foll ow-up of 35.5 months. Despite MBP reduction from 126.8 +/- 1.3 to 96.5 +/- 1.1 mm Hg (P < 0.0001), P-cr level increased from 1.5 +/- 0.1 to 1.9 +/- 0. 2 mg/dL (P < 0.01). Multivariate regression analysis showed that smoking, g reater initial P-cr level, and black ethnicity were the only examined param eters that independently predicted both a decrease in the 1/P-cr slope and calculated GFR with at least 95% confidence. Smoking was by far the most po werful of the examined factors, with initial P-cr and ethnicity being much less predictive. These studies show for the first time that smoking is an i ndependent risk factor for renal function decline in patients with severe e ssential hypertension. (C) 2000 by the National Kidney Foundation, Inc.