So who’s right?
The answer is still fuzzy, Dr. Baldwin said. Things looked pretty good for isotretinin through 2009, when a Canadian study looked at 12 years of data on 1 million Manitoba residents. There were no significant associations between the drug and the disease in the case-control analysis.
But earlier this year, an American team came up with a slightly different conclusion. Looking at about 15 million people in 12 health care claims databases, the authors concluded that 24 cases and 36 controls had been exposed to isotretinoin. Cases were 4.5 times more likely than controls to develop ulcerative colitis, but there was no link between the drug and Crohn’s disease.
“With our two most vigorous studies showing conflicting data, we are left not knowing what to do,” Dr. Baldwin said. “It’s very likely there will ever be a reliable conclusion because of the very low incidence of IBD.”
In the meantime, she said, the best physicians can do is strongly warn patients (and their parents) to be on the lookout for GI symptoms, and to report them immediately. The warning must be repeated at every follow-up visit and the medication discontinued if anything untoward develops.
The reality? As Oscar Wilde said, “The truth is rarely pure – and never simple.”
– Michele Sullivan (@MGSullivan on Twitter)