Impact of achieved blood pressure on renal function decline and first stroke in hypertensive patients with chronic kidney disease

Many cases of end-stage renal disease (ESRD) are ascribed to hypertension. However, because renal disease itself can raise blood pressure, some investigators argue that ESRD seen in patients with hypertension is due to underlying primary renal disease. Previous cohort studies of the relationship between blood pressure and ESRD did not uniformly screen out baseline kidney disease. We conducted a historical cohort study among members of Kaiser Permanente of Northern California, a large integrated health care delivery system. The ESRD cases were ascertained by matching with the US Renal Data System registry. A total of 316 675 adult Kaiser members participated in the Multiphasic Health Checkups from 1964 to 1985. All subjects had estimated glomerular filtration rates of 60 mL /min per 1.73 m(2) or higher and negative dipstick urinalysis results for proteinuria or hematuria. During 8 210 431 person-years of follow-up, 1149 cases of ESRD occurred. Compared with subjects with a blood pressure less than 120/80 mm Hg, the adjusted relative risks for developing ESRD were 1.62 (95% confidence interval [CI], 1.27-2.07) for blood pressures of 120 to 129/80 to 84 mm Hg, 1.98 (95% CI, 1.55-2.52) for blood pressures of 130 to 139/85 to 89 mm Hg, 2.59 (95% CI, 2.07-3.25) for blood pressures of 140 to 159/90 to 99 mm Hg, 3.86 (95% CI, 3.00-4.96) for blood pressures of 160 to 179/100 to 109 mm Hg, 3.88 (95% CI, 2.82-5.34) for blood pressures of 180 to 209/110 to 119 mm Hg, and 4.25 (95% CI, 2.63-6.86) for blood pressures of 210/120 mm Hg or higher. Similar associations between blood pressure level and ESRD risk were seen in all subgroup analyses. Even relatively modest elevation in blood pressure is an independent risk factor for ESRD. The observed relationship does not appear to be due to confounding by clinically evident baseline kidney disease.