Risk stratification by 24-hour ambulatory blood pressure and estimated glomerular filtration rate in 5322 subjects from 11 populations

Abstract

No previous study addressed whether in the general population estimated glomerular filtration rate (eGFR [Chronic Kidney Disease Epidemiology Collaboration formula]) adds to the prediction of cardiovascular outcome over and beyond ambulatory blood pressure. We recorded health outcomes in 5322 subjects (median age, 51.8 years; 43.1% women) randomly recruited from 11 populations, who had baseline measurements of 24-hour ambulatory blood pressure (ABP24) and eGFR. We computed hazard ratios using multivariable-adjusted Cox regression. Median follow-up was 9.3 years. In fully adjusted models, which included both ABP24 and eGFR, ABP24 predicted (P≤0.008) both total (513 deaths) and cardiovascular (206) mortality; eGFR only predicted cardiovascular mortality (P=0.012). Furthermore, ABP24 predicted (P≤0.0056) fatal combined with nonfatal events as a result of all cardiovascular causes (555 events), cardiac disease (335 events), or stroke (218 events), whereas eGFR only predicted the composite cardiovascular end point and stroke (P≤0.035). The interaction terms between ABP24 and eGFR were all nonsignificant (P=0.082). For cardiovascular mortality, the composite cardiovascular end point, and stroke, ABP24 added 0.35%, 1.17%, and 1.00% to the risk already explained by cohort, sex, age, body mass index, smoking and drinking, previous cardiovascular disease, diabetes mellitus, and antihypertensive drug treatment. Adding eGFR explained an additional 0.13%, 0.09%, and 0.14%, respectively. Sensitivity analyses stratified for ethnicity, sex, and the presence of hypertension or chronic kidney disease (eGFR <60 mL/min per 1.73 m) were confirmatory. In conclusion, in the general population, eGFR predicts fewer end points than ABP24. Relative to ABP24, eGFR is as an additive, not a multiplicative, risk factor and refines risk stratification 2-to 14-fold less. © 2012 American Heart Association, Inc.