Cockcroft-Gault is better than the Modification of Diet in Renal Disease study formula at predicting outcome after a myocardial infarction: data from the Swedish Web-system for Enhancement and Development of Evidence-based care in Heart disease Evaluated According to Recommended Therapies (SWEDEHEART)

Abstract

Background: The aim was to examine whether the Modification of Diet in Renal Disease (MDRD) or the Cockcroft-Gault (CG) formula is better at predicting prognosis in myocardial infarction (MI) patients.

Methods: All consecutive MI patients entered in a nationwide registry between 2003 and 2006 with glomerular filtration rate (eGFR) estimated by both the MDRD and CG formula (N = 36,137) were analyzed.

Results: Cockcroft-Gault classified a larger proportion of patients as having at least a moderate (39.8% vs 31.1%, P < .001) or at least a severe renal dysfunction (7.6% vs 4.4%, P < .001) compared with the MDRD. The largest difference between the estimations was seen when patients were divided according to gender, age, and weight, where CG estimated a lower eGFR in women, the elderly, and those with low body weight. In a receiver operating characteristic analysis, CG had a stronger association to 1-year mortality (area under the curve 0.78, 95% CI 0.77-0.79) than MDRD (area under the curve 0.73, 95% CI 0.72-0.74). Within each renal function stage classified with the MDRD, there were patients identified with the CG as having both a worse renal function and a higher mortality. After multivariable adjustment, CG predicted 1-year mortality better than the MDRD (renal failure vs normal renal function: hazard ratio 3.00, 95% CI 2.42-3.71 with the CG; hazard ratio 2.56, 95% CI 2.10-3.11 with the MDRD).

Conclusion: Cockcroft-Gault is better than the MDRD equation at predicting mortality after a MI. This is mainly explained by differences in the coefficients and variables included in the eGFR equations, and less to differences in various subgroups of patients.