Chronic kidney disease may be overestimated in the elderly

Current chronic kidney disease (CKD) definitions that do not consider age-related estimated glomerular filtration rate (eGFR) decline may inflate the burden of CKD in the elderly, according to a study published online Aug. 30 in JAMA Internal Medicine.

Ping Liu, Ph.D., from the University of Calgary in Alberta, Canada, and colleagues compared the outcomes associated with CKD defined by a fixed versus an age-adapted eGFR threshold. The analysis included administrative and laboratory data from adults with incident CKD from April 1, 2009, to March 31, 2017 (127,132 in the fixed cohort and 81,209 in the age-adapted cohort). The fixed eGFR threshold was 60 mL/min/1.73 m2 versus thresholds of 75, 60, and 45 mL/min/1.73 m2 for age younger than 40 years, 40 to 64 years, and 65 years and older, respectively.

The researchers found that the fixed-threshold cohort had lower risks for kidney failure (1.7 versus 3.0 percent at five years) and death (21.9 versus 25.4 percent) compared with the age-adapted cohort. Among 54,342 people ages 65 years and older with baseline eGFR of 45 to 59 mL/min/1.73 m2 and normal/mild albuminuria who were in the fixed-threshold cohort only, five-year risks for kidney failure and death were similar to those of non-CKD controls, with a risk for kidney failure of ≤0.12 percent in both groups across all age categories. Further, the risk for death in this group was 69 times higher than the risk for kidney failure at age 65 to 69 years, 122 times higher at age 70 to 74 years, 279 times higher at age 75 to 79 years, and 935 times higher at age 80 years and older.

“Current criteria for CKD that use the same eGFR threshold for all ages may result in overestimation of the CKD burden in an aging population, overdiagnosis, and unnecessary interventions in many elderly people who have age-related loss of eGFR,” the authors write.

One author disclosed a patent for a Dialysis Measurement Analysis and Reporting (DMAR) data system.