In their excellent article, Ensrud and colleagues1 found a significant relationship between estimated glomerular filtration rates (eGFRs) and fractures among elderly white women with mild chronic kidney disease (CKD). Interestingly, the relationship was only significant when the Cockcroft-Gault method was used to calculate eGFR. When the 4 variable Modification of Diet in Renal Disease (MDRD) equation was applied, the association was not significant. One possible explanation for the discrepancy noted by Sprague2 in his accompanying editorial may be an underestimation of GFR by the MDRD equation among patients with moderate CKD.
Thorp ML. Glomerular Filtration Rate Results Reflect Estimation. Arch Intern Med. 2007;167(17):1905–1906. doi:10.1001/archinte.167.17.1905-b