By Bruce Sylvester
SAN DIEGO -- October 30, 2009 -- Results from a retrospective study presented here at the American College of Gastroenterology (ACG) 74th Annual Scientific Meeting suggest that use of isotretinoin is associated with the development of inflammatory bowel disease (IBD).
"We performed a case control study looking at the connection between [isotretinoin] and inflammatory bowel disease," said lead investigator Seth Crockett, MD, University of North Carolina Medical School at Chapel Hill, Chapel Hill, North Carolina, on October 27.
"We found that there did appear to be an association between prior [isotretinoin] use and subsequent development of ulcerative colitis. There appeared to be approximately a 4 times increased risk for those who had taken [isotretinoin] compared with those who had not."
The researchers extracted data from a claims database containing information on 55 million patients from over 70 health plans in the United States (PharMetrics, IMS Health, Watertown, MA).
From those with at least 12 months of continuous health plan enrolment, they identified cases of Crohn's disease, ulcerative colitis, and indeterminate IBD. They matched each case (n = 8,189; 56% female) to 3 non-IBD controls (n = 21,832; 56% female) on the basis of age, gender, and geographical region.
They evaluated case records for isotretinoin exposure in the 12 months prior to the first IBD diagnosis, or in the first 12 months of enrolment for controls. They used standard statistical analysis to compare cases with controls.
Case records showed that 3,664 (45%) had Crohn's disease, 4,428 (54%) had ulcerative colitis, and 97 (1%) had indeterminate IBD.
The researchers identified prior isotretinoin use in the records of 60 subjects (24 cases and 36 controls).
They reported that the unadjusted odds ratio (OR) of IBD for isotretinoin use was 1.78 (95% confidence interval [CI], 1.02-3.07). After adjusting for potential confounding variables (age, sex, geographic region), the OR decreased slightly to 1.68 (95% CI, 0.98-2.86).
Dr. Crockett noted that an increase in per-patient prescriptions of isotretinoin was associated with an increasing IBD risk. Four or more prescriptions associated with an OR of 2.67 (95% CI, 1.32-5.41).
He also reported that ulcerative colitis was strongly associated with prior isotretinoin use (OR = 4.36; 95% CI, 1.97-9.66), and that the analysis showed no association between isotretinoin use and Crohn's disease (OR = 0.68; 95% CI, 0.28-1.68).
Dr. Crockett and colleagues concluded that more studies are needed to confirm their findings in other populations, and to describe, on a biological level, the relationship between isotretinoin and the risk of IBD.
Funding for this study was provided by the US National Institutes of Health.
[Presentation title: Accutane Use Is Associated With Inflammatory Bowel Disease: A Case Control Study Using Administrative Data. Abstract 1122]
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