Blood pressure and renal function decline: a 7-year prospective cohort study in middle-aged rural Chinese men and women.

BACKGROUND: The most recent guidelines for the management of hypertension (Eighth Joint National Committee) indicate the need of more evidence for hypertensive persons aged below 60 years. We sought to examine the relationship between baseline blood pressure (BP) and renal function decline in a 7-year prospective cohort study of 2383 rural Chinese men and women aged 40-60 years.

METHODS: Multiple linear and logistic regressions were applied to estimate sex-specific associations between baseline BP level and annual estimated glomerular filtration rate (eGFR) change estimated by the Chronic Kidney Disease Epidemiology Collaboration method and rapid eGFR decline (>3 ml/min per 1.73 m per year), respectively. Regression coefficients or odds ratios (ORs) [95% confidence interval (CI)] were presented, with adjustment for age, BMI, cigarette smoking, alcohol consumption, total cholesterol level, triglycerides, fasting glucose and physical activity level. Furthermore, we examined if the associations varied by baseline eGFR strata.

RESULTS: There was a dose-response association between baseline SBP/DBP and annual eGFR decline (P for trend <0.001). When stratified by baseline eGFR strata (low <110 vs. high ≥110), the highest risk of rapid eGFR decline was found in men with low baseline eGFR and SBP above 140  mm Hg (OR 2.9, 95% CI 1.6-5.1) or DBP above 90  mm Hg (OR 2.7, 95% CI 1.6-4.6), and there was a significant interaction between baseline SBP/DBP and eGFR strata on renal function decline in men, but not in women.

CONCLUSION: In this prospective cohort of middle-aged Chinese adults, we showed a dose-response relationship between baseline SBP/DBP and eGFR decline without a clear threshold, and such relationship differed remarkably by sex and baseline eGFR level. Men with eGFR below 110 were particularly vulnerable to the adverse renal effects of elevated SBP and DBP.