Chronic kidney disease staging in nursing home and community older adults: Does the choice of cockcroft-gault, modification of diet in renal disease study, or the chronic kidney disease epidemiology collaboration initiative equations matter?

Objective: To compare the chronic kidney disease (CKD) stages derived from GFR estimates using 3 different formulae in a sample of older adults from the community and long term care settings. Participants: Data from 1535 older, hospitalized patients (2000-2008) were collected; individuals werehospitalized for acute illness unrelated to renal function. Measurements: Patient demographics, pertinent medical history, and routine laboratory test results were collected. Estimate of glomerular filtration rate and creatinine clearance values were determined by the Cockcroft-Gault, Modification of Diet in RenalDisease Study, and Chronic Kidney Disease Epidemiology Collaboration equations. Results: The Cockcroft-Gault equation generated significantly lower mean estimate of glomerular filtration rate values than either Modification of Diet in Renal Disease Study or Chronic Kidney Disease Epidemiology Collaboration equations in the total sample (P < .0005) and in a subset of patients diagnosed as renal insufficiency (P < .00005). Using the 3formulae produced a significant disconnect in CKD staging resulting in the potential for different recommendations for monitoring and management across formulae (National Kidney Foundation Guidelines) (P < .0005). When stratified by age, the 3 equations produce nearly identical glomerular filtration rate estimates in patients younger than 70 years (P= .989) but significantly different glomerular filtration rate estimates in patients from 70 to 104 years (P < .0005). Conclusions: The Cockcroft-Gault equation systematically provides lower (more severe) estimates of renalfunction than the Modification of Diet in RenalDiseaseStudy and Chronic Kidney Disease Epidemiology Collaboration equation in patients older than 70 years. However, significant differences in CKD staging derived from estimate of glomerular filtration rate or creatinine clearance were not observed in adults from 59 to 69 years of age. These findings do not validate one formula over the others, but demonstrate that disparities exist; it may be prudent to use the same formula over time in a given patient to monitor changes in renal function.