Lower estimated glomerular filtration rate and higher albuminuria are associated with all-cause and cardiovascular mortality. A collaborative meta-analysis of high-risk population cohorts

Screening for chronic kidney disease is recommended in people at high risk, but data on the independent and combined associations of estimated glomerular filtration rate (eGFR) and albuminuria with all-cause and cardiovascular mortality are limited. To clarify this, we performed a collaborative meta-analysis of 10 cohorts with 266,975 patients selected because of increased risk for chronic kidney disease, defined as a history of hypertension, diabetes, or cardiovascular disease. Risk for all-cause mortality was not associated with eGFR between 60-105 ml/min per 1.73 m², but increased at lower levels. Hazard ratios at eGFRs of 60, 45, and 15 ml/min per 1.73 m² were 1.03, 1.38 and 3.11, respectively, compared to an eGFR of 95, after adjustment for albuminuria and cardiovascular risk factors. Log albuminuria was linearly associated with log risk for all-cause mortality without thresholds. Adjusted hazard ratios at albumin-to-creatinine ratios of 10, 30 and 300 mg/g were 1.08, 1.38, and 2.16, respectively compared to a ratio of five. Albuminuria and eGFR were multiplicatively associated with all-cause mortality, without evidence for interaction. Similar associations were observed for cardiovascular mortality. Findings in cohorts with dipstick data were generally comparable to those in cohorts measuring albumin-to-creatinine ratios. Thus, lower eGFR and higher albuminuria are risk factors for all-cause and cardiovascular mortality in high-risk populations, independent of each other and of cardiovascular risk factors.