Bolen E, Stern K, Humphreys M, et al. - In this largest study of transplant nephrolithiasis, kidney transplant recipients who were diagnosed with transplant nephrolithiasis were retrospectively evaluated for retrieving data on urine metabolic risk factors and presence of stones after follow-up.

• Researchers identified data of 6,548 kidney transplant recipients between 2009–2019; incidence of allograft kidney stone formation was 0.86%.

• There were 56 cases, 17 of whom (30%) had pretransplant history of nephrolithiasis.

• A known kidney stone was received by only 4 (7%) patients at the time of allograft implantation.

• The most significant urine metabolic risk factors associated with allograft nephrolithiasis were hypocitraturia and hyperoxaluria and the most prevalent driver for calcium oxalate stone composition was hyperoxaluria.

• In this study, for the first time, low stone free rates at last follow-up are shown and there was a significant proportion that required surgical intervention.