Wednesday, May 13, 2015

Goldfarb takes the ACP to the woodshed

David Goldfarb has written a sternly worded letter to the ACP in response to their clinical practice guideline, Dietary and pharmacologic management to prevent recurrent nephrolithiasis in adults. The guidelines took positions that seemed to make no sense when looked at as a whole. Due to insufficient evidence the guidelines recommend:

  • no need to determine stone composition prior to treating stones
  • no need to analyze blood chemistry before treating stones
  • no need to do 24-hour (or 48-hour) urine collections before treating stones
What makes those positions so absurd is that if increased fluid intake did not reduce stones the authors suggested a trial of allopurinol, thiazide diuretics or citrate (without guidance on how to dose, follow or how to choose among those therapies). These recommendations are based on research done on patients where the type of stone had been determined. Not following those enrollment criteria makes the conclusions irrelevant.

It is as if the ACP said not to measure blood pressure because there has never been a randomized controlled trial of patients where blood pressure was measured versus patients who do not measure blood pressure.

Goldfarb's letter added some other incredible details to the story I was unaware of including:
None of the authors of the paper have a single other co-authorship in PubMed relevant to kidney stones, other than the AHRQ review. I believe that none of the authors are nephrologists or urologists, none have a kidney stone clinic, none appear at, or present research at, kidney stone meetings, none have any experience regarding management of kidney stones
And this doozy, in response to a comment of the paper from the lead author:

As we point out in the guideline, we are aware that many physicians do select medications based on stone type, for example, allopurinol for uric acid stones, and we do not discourage that practice. 

Physicians who regularly treat stones or who played NephMadness (2014 edition) know that allopurinol is used to prevent calcium stones not uric acid stones which are best treated with alkalinization.

Read Goldfarb's letter. It is excellent.
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