KDIGO clinical practice guidelines for bisphosphonate treatment in chronic kidney disease

To the Editor: We have read the letter to the editor by Jerzy Przedlacki1 and the response from the authors2 of the Kidney Disease-Improving Global Outcomes (KDIGO) clinical practice guidelines for bisphosphonate (BP) treatment in chronic kidney disease (CKD), and would like to share our concerns regarding the use of BP treatment of CKD. The kidney is the organ that excretes many drugs, and any change in renal function will affect the pharmacology of these drugs. Existing or residual renal function of the patient will have to be taken into account while prescribing drugs. This is just as important for the patient with CKD 4 or 5, including those with CKD 5 already on peritoneal dialysis or hemodialysis, who may still have residual renal function. Nephrotoxic drugs including nonsteroidal anti-inflammatory drugs can very readily destroy whatever residual renal function patients may still have. Residual renal function is important to preserve as it contributes to less patient morbidity and mortality3 in the dialysis patient. Recently, there have been adverse reports of a certain BP that works by inhibiting osteoclast-mediated bone resorption, thereby slowing the breakdown of bone to reduce the risk of fractures. As of 14 August 2009, there have been 139 post-marketing reports of renal impairment following its use as an infusion worldwide. Many of these occur in patients with pre-existing medical conditions or risk factors (elderly, renal impairment, and/or concurrent dehydration), or in those on nonsteroidal anti-inflammatory drugs or other concurrent exposure to other nephrotoxic agents. There have also been cases requiring dialysis, and occasional fatal outcomes have been reported in patients with pre-existing renal impairment and concomitant risk factors.4, 5, 6, 7