To the Editor: In their randomized trial comparing sodium bicarbonate vs sodium chloride for prevention of contrast medium–induced nephropathy (CIN), Dr Brar and colleagues1 used a lower dose of bicarbonate than described in other studies2- 4 and found that this lower dose of bicarbonate was inadequate to significantly reduce CIN. Their study did not document urine pH as was done in other studies.2,3,5 The bicarbonate concentration in their study was 130 mEq/L compared with 154 mEq/L in the other studies. The administered dose of bicarbonate anion was higher in the studies by Merten et al2 (by 18%), Ozcan et al3 (by 58%), and Recio-Mayoral et al4 (by 202%). The higher doses would likely result in a higher urine pH, although the bicarbonate effect on urine pH is nonlinear.
Burgess W, Merten GJ, Rittase RA. Sodium Bicarbonate vs Sodium Chloride in Preventing Contrast Medium–Induced Nephropathy. JAMA. 2009;301(4):377-380. doi:10.1001/jama.2009.16