Cockcroft-Gault versus modification of diet in renal disease: importance of glomerular filtration rate formula for classification of chronic kidney disease in patients with non-ST-segment elevation acute coronary syndromes.

OBJECTIVES: Our purpose was to compare formulae for estimating glomerular filtration rate (GFR) in non-ST-segment elevation acute coronary syndromes (NSTE ACS) patients.
BACKGROUND: Assessment of GFR is important for antithrombotic dose adjustment in NSTE ACS patients.
METHODS: We assessed estimated glomerular filtration rate (eGFR) with Cockcroft-Gault (C-G) and Modification of Diet in Renal Disease (MDRD) formulae in 46,942 NSTE ACS patients from 408 CRUSADE (Can Rapid risk stratification of Unstable angina patients Suppress ADverse outcomes with Early implementation of the American College of Cardiology/American Heart Association Guidelines) hospitals. Formula agreement was shown continuously and by chronic kidney disease (CKD) stages. We determined in-hospital outcomes and the association between antithrombotic dose adjustment and bleeding for moderate CKD as determined by each formula.
RESULTS: The median (interquartile range [IQR]) eGFR was 53.2 ml/min (34.7, 75.1 ml/min) by C-G and 65.8 ml/min (47.6, 83.5 ml/min) by MDRD. The mean eGFR was higher with MDRD (approximately 9.1 ml/min), but this difference was greater in age, weight, and gender subgroups. Chronic kidney disease classification differed in 20% of the population and altered when antithrombotic dose adjustment was required by C-G versus MDRD (eptifibatide: 45.7% vs. 27.3%; enoxaparin: 19.0% vs. 9.6%).
CONCLUSIONS: Important CKD disagreements occur in approximately 20% of acute coronary syndrome patients, affecting dosing adjustments in those already susceptible to bleeding. Dosing based on C-G formula is preferable, particularly in the small, female, or elderly patient.