Smaller Declines in Kidney Function Still Predict ESRD and Death

Kidney function declines of less than a doubling of serum creatinine are common and are strong predictors of ESRD and mortality, according to a meta-analysis in the Journal of the American Medical Association.

The analysis included individual-level data on 1.7 million patients from 35 cohorts included in the CKD Prognosis Consortium, including repeated measurements of serum creatinine over 1 to 3 years. The 2-year percentage change in eGFR was analyzed as a predictor of all-cause mortality and ESRD, with adjustment for confounders and baseline eGFR. The analysis included a total of 12,344 ESRD events and 223,944 deaths.

Greater declines in eGFR carried larger increases in risk for both outcomes. For patients with a baseline eGFR less than 60 mL/min/1.73 m2, the adjusted hazard ratio for ESRD was 32.1 with a 57 percent drop in eGFR versus 5.4 for a 30 percent reduction. However, the larger decline in eGFR occurred in just 0.79 percent of patients, whereas the smaller decline occurred in 6.9 percent.

The association was consistent across groups defined by length of baseline period, baseline eGFR level, patient age, diabetes status, or albuminuria. At a baseline eGFR of 35 mL/min/1.73 m2, the adjusted 10-year risks of ESRD were 99 percent for patients with a 57 percent reduction in eGFR, 83 percent with a 40 percent reduction, 64 percent with a 30 percent reduction, and 18 percent with no change in eGFR. The risks of death were 77 percent, 60 percent, 50 percent, and 32 percent, respectively.

Doubling of serum creatinine—corresponding to a 57 percent reduction in eGFR—is typically regarded as a late event in CKD. The new study shows that lesser declines in kidney function are much more common but are still “strongly and consistently” associated with an increased risk of ESRD and death. The authors suggest that a 30 percent reduction in eGFR over 2 years might be a useful alternative end point in studies of CKD progression [Coresh J, et al. Decline in estimated glomerular filtration rate and subsequent risk of end-stage renal disease and mortality. JAMA 2014; 311:2518–2531].