Rapid Kidney Function Decline and Mortality Risk in Older Adults

TLDR

Impaired kidney function is associated with increased mortality risk in older adults. The study investigates whether longitudinal declines in kidney function independently predict cardiovascular and all‑cause mortality in older adults. Using the Cardiovascular Health Study cohort, the authors estimated annual eGFR decline from serial creatinine and cystatin C measurements at baseline, year 3, and year 7, defining rapid decline as >3 mL/min/1.73 m² per year and following participants for ~10 years to assess mortality. Rapid eGFR decline, whether measured by creatinine or cystatin C, was associated with a 53–70 % higher risk of cardiovascular and all‑cause mortality, independent of baseline kidney function and other demographics.

Abstract

Impaired kidney function is associated with increased mortality risk in older adults. It remains unknown, however, whether longitudinal declines in kidney function are independently associated with increased cardiovascular and all-cause mortality in older adults.The Cardiovascular Health Study evaluated a cohort of community-dwelling older adults enrolled from 1989 to 1993 in 4 US communities with follow-up through 2005. Among 4380 participants, the slope of annual decline in estimated glomerular filtration rate (eGFR) was estimated using both serum creatinine (eGFR(creat)) and cystatin C (eGFR(cys)) rates, which were measured at baseline, year 3, and year 7 of follow-up. Rapid decline in eGFR was defined as a loss greater than 3 mL/min/1.73 m(2) per year, and cardiovascular and all-cause mortality were assessed over a mean of 9.9 years of follow-up.Mean (SD) levels of creatinine and cystatin C were 0.93 (0.30) mg/dL and 1.03 (0.25) mg/L, respectively; mean (SD) eGFR(creat) and eGFR(cys) were 79 (23) mL/min/1.73 m(2) and 79 (19) mL/min/1.73 m(2), respectively. Individuals with rapid decline measured by eGFR(creat) (n = 714; 16%) had increased risk of cardiovascular (adjusted hazard ratio [AHR], 1.70; 95% confidence interval [CI], 1.40-2.06) and all-cause (AHR, 1.73; 95% CI, 1.54-1.94) mortality. Individuals with rapid decline measured by eGFR(cys) (n = 1083; 25%) also had increased risk of cardiovascular (AHR, 1.53; 95% CI, 1.29-1.80) and all-cause (AHR, 1.53; 95% CI, 1.38-1.69) mortality. The association of rapid decline in eGFR with elevated mortality risk did not differ across subgroups based on baseline kidney function, age, sex, race, or prevalent coronary heart disease.Rapid decline in eGFR is associated with an increased risk of cardiovascular and all-cause mortality in older adults, independent of baseline eGFR and other demographic variables.