In the kidney stone bracket I think the most disappointed team must be XO inhibitors. Allopurinol has been around for a long time and is one of the mainstays of treatment for gout. More recently, febuxostat hit the scene and can also lower uric acid. The most interesting issue relating to uric acid (for me) is the evidence linking elevated uric acid with risk of developing CKD. This idea is backed by experiments in rats. Raising the uric acid level in rats can induce glomerular hypertension and renal disease as noted by the development of arteriolosclerosis, glomerular injury and tubulointerstitial fibrosis. Some pilot studies in human suggest that lowering uric acid levels can slow the progression of renal disease. If these findings are significant large RCTs, the old man Allopurinol and the young pup febuxostat would be catapulted into the stratosphere! A good review of this literature is found here. Despite these interesting findings, CT scan beat XO inhibitors for me. I think CT scanning, for good or for bad, is ubiquitous in medicine and won by shear prevalence! Another very interesting match up and some learning for me was the Dr Pak vs Dr Coe match-up, two heavy weights of renal stone disease. I vaguely remember learning about Randall’s plaques and supersaturation of urine years ago. The loser of this match up must surely be disappointed!