Inflammatory bowel disease patients risk developing stones

Inflammatory bowel disease (IBD) is associated with a heightened risk of urolithiasis both before and after diagnosis, a study has found. This association is especially pronounced in patients exposed to antitumour necrosis factor (anti-TNF) therapy and those who have undergone surgery, suggesting that IBD severity and surgery contribute to a risk increase.

The study included 75,236 IBD patients (50,525 with ulcerative colitis [UC] and 24,711 with Crohn’s disease [CD]) and 767,403 matched controls. IBD patients were more likely to have medium-length education (p<0.001) and a higher comorbidity burden (p<0.001), but there was no significant difference in the number of urogenital malformations (p=0.34) compared with controls.

Over a median follow-up of 11 years, covering 989,280 person-years in the IBD group and 10,423,557 person-years in the control group, a total of 2,549 patients and 11,258 controls developed urolithiasis (3 percent vs 2 percent; p<0.001).

There was a twofold increased risk of urolithiasis in the IBD than the control group (hazard ratio [HR], 2.27, 95 percent confidence interval [CI], 2.17–2.38), with higher estimates for CD (HR, 2.89, 95 percent CI, 2.67–3.12) than for UC (HR, 1.95, 95 percent CI, 1.84–2.07).

The IBD group also had a higher risk of repetitive events of urolithiasis (20 percent vs 14 percent; p<0.001; rate ratio [RR] 1.09, 95 percent CI, 1.04–1.15).

Results of an analysis stratified by time of IBD diagnosis showed a similar pattern. The risk of urolithiasis was elevated prior to IBD diagnosis (OR, 1.42, 95 percent CI, 1.34–1.50) and after diagnosis. IBD patients treated with anti-TNF (RR_UC, 2.68, 95 percent CI, 1.98–3.63; RR_CD, 3.56, 95 percent CI, 2.72–4.66) and who had undergone previous surgery (RR_UC, 3.14, 95 percent CI, 2.46–4.01; RR_CD, 2.74, 95 percent CI, 2.12–3.54) were particularly at risk.

In light of the findings, subpopulations of IBD patients, especially those undergoing strong immunosuppression, may benefit from additional urolithiasis screening to facilitate early detection and treatment, as stone formation is associated with adverse outcomes including sepsis.