Laparoscopic Roux-en-Y gastric bypass elevates the risk of kidney stone formation

According to a pair of studies. The two studies—one from the University of Minnesota, Minneapolis, and a second led by researchers from Wake Forest University Baptist Medical Center, Winston-Salem, NC—had relatively short follow-up periods of 1 year and 6 months, respectively. Owing to their brevity, neither study found an increased incidence of stones among the patients undergoing the surgery, but both found significant increases in oxalate secretion.

Both also found a supersaturation of calcium oxalate in a number of patients relatively soon after the surgical procedure. "The take-home message from our study is that morbidly obese patients should be counseled regarding the increased risks for kidney stones postoperatively," Bryan Hinck, a former research assistant for senior author Manoj Monga, MD, at the University of Minnesota, told Urology Times. "Not that this should dissuade them from the surgery, but rather inform them of the importance of compliant follow-up."

Hinck is currently a medical student at Rosalind Franklin University's Chicago Medical School.
"Based on our findings, patients who have gastric bypass are at increased risk for forming stones," added Bhavin N. Patel, MD, a Wake Forest urology resident who worked on that group's study with Dean G. Assimos, MD, and colleagues. "Indeed, some are at increased risk of nephropathy and perhaps irreversible kidney damage."

Source: Urology Times