Original Research: COPDUrinary Albumin-Creatinine Ratio, Estimated Glomerular Filtration Rate, and All-Cause Mortality Among US Adults With Obstructive Lung Function

BACKGROUNDElevated urinary albumin-creatinine ratio (UACR) and decreased estimated glomerular filtration rate (eGFR) predict all-cause mortality, but whether these markers of kidney damage and function do so in adults with obstructive lung function (OLF) is unclear. The objective of this study was to examine the associations between UACR and eGFR and all-cause mortality in adults with OLF.METHODSData of 5,711 US adults aged 40 to 79 years, including 1,390 adults with any OLF who participated in the National Health and Nutrition Examination Survey III (1988-1994), were analyzed. Mortality follow-up was conducted through 2006.RESULTSDuring the median follow-up of 13.7 years, 650 adults with OLF died. After maximal adjustment, mean levels of UACR were higher in adults with moderate-severe OLF (7.5 mg/g; 95% CI, 6.7-8.5) than in adults with normal pulmonary function (6.2 mg/g; 95% CI, 5.8-6.6) (P = .003) and mild OLF (6.2 mg/g; 95% CI, 5.5-6.9) (P = .014). Adjusted mean levels of eGFR were lower in adults with moderate-severe OLF (87.6 mL/min/1.73 m2; 95% CI, 86.0-89.1) than in adults with normal lung function (89.6 mL/min/1.73 m2; 95% CI, 88.9-90.3) (P = .015). Among adults with OLF, hazard ratios for all-cause mortality increased as levels of UACR, modeled as categorical or continuous variables, increased (maximally adjusted hazard ratio for quintile 5 vs 1: 2.23; 95% CI, 1.56-3.18). eGFR, modeled as a continuous variable but not as quintiles, was significantly associated with mortality.CONCLUSIONSUACR and eGFR, in continuous form, were associated with all-cause mortality among US adults with OLF.