Study designs of evaluations included in the review
All study designs appear to have been eligible for inclusion. The included studies were all retrospective observational studies.
Specific interventions included in the review
Studies were eligible for inclusion if they reported outcomes associated with individual immunomodulator drugs. The immunomodulator drugs used in the included studies were azathioprine, 6-mercaptopurine, cyclosporin, methotrexate and infliximab. These were sometimes taken in combination with corticosteroids (with some controls being on corticosteroids as well).
Participants included in the review
IBD patients treated with immunomodulator drugs who underwent abdominal surgery without discontinuation of the drug were eligible for inclusion in the intervention group. The included patients had CD or UC. The patients in the control groups were frequently taking corticosteroids and in some cases were taking a different immunomodulator.
Outcomes assessed in the review
Studies that included post-operative infective or total complication rates associated with the use of individual immunomodulator drugs were eligible for inclusion. The specific post-operative complications tracked varied between studies.
How were decisions on the relevance of primary studies made?
The authors did not state how the papers were selected for the review, or how many reviewers performed the selection.