Muscle mass and estimates of renal function: a longitudinal cohort study

Abstract Background Creatinine is the most widely used test to estimate the glomerular filtration rate (GFR), but muscle mass as key determinant of creatinine next to renal function may confound such estimates. We explored effects of 24‐h height‐indexed creatinine excretion rate (CER index) on GFR estimated with creatinine (eGFRCr), muscle mass‐independent cystatin C (eGFRCys), and the combination of creatinine and cystatin C (eGFRCr‐Cys) and predicted probabilities of discordant classification given age, sex, and CER index. Methods We included 8076 adults enrolled in the PREVEND study. Discordant classification was defined as not having eGFRCr