We thank Kshirsagar and Colindres for their comments on our article.1 Because we analyzed the percentage change in serum creatinine concentration between visits 1 and 2 of the ARIC study and because creatinine assays for the first 2 ARIC visits were performed at the same laboratory (University of Minnesota) with very similar calibration, there was no need to adjust to the Cleveland Clinic laboratory. We did not use the Modification of Diet in Renal Disease equation and did not classify glomerular filtration rate estimates.2,3 We therefore see no possibility of misclassification bias.
O’Hare AM, Rodriguez RA, Bacchetti P. Systemic Atherosclerosis and Kidney Disease—Reply. Arch Intern Med. 2006;166(2):250. doi:10.1001/archinte.166.2.250-b