Thiopurines are the mainstay of treatment for patients with inflammatory bowel disease (IBD). Thiopurine therapy increases the risk of nonmelanoma skin cancers in organ transplant patients.
The data on nonmelanoma skin cancers in patients with IBD on thiopurines is conflicting.
Drs Jonathan Ariyaratnam and Venkataraman Subramanian from the United Kingdom searched electronic databases for full journal articles reporting on the risk of developing nonmelanoma skin cancers in patients with IBD on thiopurine, and hand searched the reference lists of all retrieved articles.
Pooled adjusted hazard ratios and 95% confidence intervals were determined using a random-effects model.
Publication bias was assessed using Funnel plots and Egger's test.
|Hazards ratio of developing nonmelanoma skin cancers after exposure to thiopurines was 2.28|
|American Journal of Gastroenterology|
Heterogeneity was assessed using Cochran's Q and the I2 statistic.
The team identified 8 studies involving 60,351 patients provided data on the risk of developing nonmelanoma skin cancers in patients with IBD on thiopurines.
The pooled adjusted hazards ratio of developing nonmelanoma skin cancers after exposure to thiopurines in patients with IBD was 2.28.
The team observed significant heterogeneity between the studies but no evidence of publication bias.
Meta regression analysis suggested that the population studied, and duration of follow-up contributed significantly to heterogeneity.
The team found that grouping studies based on population studied and duration showed higher hazard rations in hospital-based and shorter duration studies.
Dr Subramanian and colleague commented, "The risk of developing nonmelanoma skin cancers in patients with IBD on thiopurines is only modestly elevated."
"The difference in pooled risk between population-based and hospital-based studies suggests the possibility that ascertainment bias could have contributed to this increased risk."