Inflammatory bowel disease case study

The relation between oral contraceptive use and inflammatory bowel disease was analysed in two case-control studies published in the 1990s (205,206). Both found a significantly increased risk among current users compared with never users for Crohn s disease, but only the former study detected an increased risk of ulcerative colitis a dose-response effect was suggested for Crohn s disease. When the data were stratified by smoking status in the latter study, the increased risk was found only among current smokers. 

Onnie CM, Fisher SA, Pattni R, et al. Associations of allelic variants of the multidrug resistance gene (ABCB1 or MDR1) and inflammatory bowel disease and their effects on disease behavior a case-control and meta-analysis study. Inflamm Bowel Dis 2006 12(4) 263-271. 

In cases of inflammatory bowel disease, no overall increased incidence of cancer was noted after a median of 9 years follow-up in 755 patients who had taken less than 2 mg/kg/day of azathioprine over a median period of 12.5 years (69). Only colorectal cancers (mostly adenocarcinoma) were more frequent, but their incidence was also increased in chronic inflammatory bowel diseases. More specifically, there was no excess of non-Hodgkin s lymphoma, but the power of the study to detect an increased risk of this disorder was low. 

In an international case-control study of 499 patients with chronic inflammatory bowel disease and 998 control patients from nine countries, there was no difference in the risk of inflammatory bowel disease in association with either natural measles or measles immunization (112). 

The causal connection between NSAIDs and large bowel inflammation needs to be confirmed by appropriate epidemiological studies. Many publications have associated NSAID and colonic inflammation (SEDA-10, 77) (SEDA-15, 95), but the differential diagnosis between colonic inflammation arising de novo and exacerbation of underlying inflammatory bowel disease can be difficult, and the role of NSAIDs in aggravating ulcerative colitis or Crohn s disease or other inflammatory bowel disease is controversial (SEDA-10, 76) (SEDA-15, 95). A case-control study showed no association between appendi-cectomy for acute appendicitis and the use of NSAIDs (SEDA-22, 111). 

Felder JB, Korelitz BI, Rajapakse R, Schwarz S, Horatagis AP, Gleim G. Effects of nonsteroidal antiinflammatory drugs on inflammatory bowel disease a case-control study. Am J Gastroenterol 2000 95(8) 1949-54. 

Although three other cases of inflammatory bowel disease during isotretinoin therapy have been reported (70-72), there have also been reports of the safe use of isotretinoin in patents with a history of inflammatory bowel disease (that is without exacerbation of the inflammatory bowel disease) (70,73,74). Since retinoids are being increasingly used to treat moderately severe acne, larger studies are needed to elucidate the relation between retinoid use and inflammatory bowel disease. 

Tumorigenidty In a nested case-control study in 15471 patients with inflammatory bowel disease, azathioprine was compared between cases with a diagnosed cancer and control patients without cancer [168 ]. There was no overall increase in the risk of any cancer in patients with inflammatory bowel disease who had taken azathioprine. 

Armstrong RG, West J, Card TR. Risk of cancer in inflammatory bowel disease treated with azathioprine a UK population-based case-control study. Am J Gastroenterol 2010 105(7) 1604—9. 

Gastrointestinal A systematic search for case reports, case series, and clinical studies of the association between isotretinoin and inflammatory bowel disease yielded 12 case reports and one case series of such an association, to which the Bradford Hill guidelines to evaluate causality [36 ] were applied [37 ]. The cases occurred in seven countries over 23 years and differed with respect to isotretinoin dose, duration of treatment before development of the disease, whether the disease developed on or off medication, and the clinical presentation. There have been no prospective or retrospective studies. An estimated 59 coincident cases of inflammatory bowel disease would be expected in isotretinoin users each year, assuming no increased risk. The current evidence is insufficient to confirm or refute a causal association. 

Observational studies Mesalazine (mesala-mine, 5-aminosalicylic acid) has been linked with tubulointerstitial nephritis in patients with inflammatory bowel disease. In a retrospective analysis of renal impairment during long-term use of aminosalicylates in 171 patients with inflammatory bowel disease, the mean daily dose was 3.65 g/day and the mean treatment duration 8.4 years treatments included mesalazine (74%), sulfasalazine (15%), and the combination (11%) [87 ]. Serum creatinine concentrations increased significantly during treatment, from 77 to 89 pmol/1, and creatinine clearance fell significantly from 105 to 93 ml/minute. The fall in creatinine clearance correlated positively with the mean daily dose. There was one case of interstitial nephritis. 

Etminan M, Bird ST, Delaney JA, Bressler B, Brophy JM. Isotretinoin and risk for inflammatory bowel disease a nested case-control study and meta-analysis of published and unpublished data. JAMA Derm 2013 149(2) 216-20. 

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