Background: Extraintestinal manifestations (EIMs) are common in Inflammatory bowel disease (IBD), adding to the burden of disease, with a prevalence varying from 6% to 46%. The mechanism of nephrolithiasis is different in Ulcerative Colitis (UC) and Crohn’s disease (CD) but it is the most common renal manifestation in both. Methods: We analyzed the National Inpatient Sample (NIS) database for all subjects with discharge diagnosis of IBD (Ulcerative Colitis & Crohn’s disease) with or without Nephrolithiasis as primary or secondary diagnosis via ICD 9 codes during the period from 2002-2014. All analyses were performed with the use of SAS (version 9.4) Results: From 2002-2014 there were total 3359 discharges of Ulcerative Colitis (UC) patients and 9741 discharges of Crohn’s Disease (CD) patients with nephrolithiasis, constituting 1.4% & 2.3% discharges respectively. Most of the patients with Nephrolithiasis were Caucasians (82.1% in UC & 87.8% in CD), with age below 65 (70.2% in UC & 79.9% in CD), males (55.9% in UC & 51.6% in CD). The odds of routine discharge were more and decreased mortality & Charlson index was found in patients with nephrolithiasis. There was a slight rise in incidence of nephrolithiasis in IBD (0.9% of UC discharges & 2.1% of CD discharges in 2002 to 1.8% of UC & 2.6% of CD discharges in 2014). Deficiency anemias, liver disease, arthritis, renal failure, fluid and electrolyte disorders and collagen vascular disorders were the significant predictors of nephrolithiasis in IBD on Multivariate regression analysis. Conclusions: Our analysis concludes that incidence of nephrolithiasis is less than the previously reported figures in some of the population studies, though the incidence is slightly more in CD then UC as previously reported. Our analysis points out an interesting finding that nephrolithiasis in IBD may be predictive of more benign outcome in hospitalized patients of IBD as observed by decreased mortality and more routine discharges.
