Risk of postoperative infectious complications from medical therapies in inflammatory bowel disease

Medications used to treat inflammatory bowel disease (IBD) have significantly improved patient outcomes and delayed time to surgery. However, some of these therapies are recognized to increase the general risk of infection and have an unclear impact on postoperative infection risk.

To assess the impact of perioperative IBD medications on the risk of postoperative infections within 30 days of surgery.

We searched the Cochrane IBD Group's Specialized Register (29 October 2019), MEDLINE (January 1966 to October 2019), Embase (January 1985 to October 2019), the Cochrane Library, ClinicalTrials.gov and the WHO International Clinical Trials Registry Platform from inception up to October 2019, and reference lists of articles.

Randomized controlled trials, quasi-randomized controlled trials, non-randomized controlled trials, prospective cohort studies, retrospective cohort studies, case-control studies and cross-sectional studies comparing participants treated with an IBD medication preoperatively or within 30 days postoperatively to those who were not taking that medication (either another active medication, placebo, or no treatment). We included published study reports and abstracts.

Two review authors independently screened titles and abstracts and extracted data. The primary outcome was postoperative infection within 30 days of surgery. Secondary outcomes included incisional infections and wound dehiscence, intra-abdominal infectious complications and extra-abdominal infections. Three review authors assessed risks of bias using the Newcastle-Ottawa Scale. We contacted authors for additional information when data were missing. For the primary and secondary outcomes, we calculated odds ratios (ORs) and corresponding 95% confidence intervals (95% CIs) using the generic inverse variance method. When applicable, we analyzed adjusted and unadjusted data separately. We evaluated the certainty of the evidence using GRADE.

We included 68 observational cohort studies (total number of participants unknown because some studies did not report the number of participants). Of these, 48 studies reported including participants with Crohn's disease, 36 reported including participants with ulcerative colitis and five reported including participants with indeterminate colitis. All 42 studies that reported urgency of surgery included elective surgeries, with 31 (74%) of those also including emergency surgeries. Twenty-four studies had low risk of bias while the rest had very high risk. Based on pooling of adjusted data, we calculated ORs for postoperative total infection rates in participants who received corticosteroids (OR 1.70, 95% CI 1.38 to 2.09; low-certainty evidence), immunomodulators (OR 1.29, 95% CI 0.95 to 1.76; low-certainty evidence), anti-TNF agents (OR 1.60, 95% CI 1.20 to 2.13; very low-certainty evidence) and anti-integrin agents (OR 1.04, 95% CI 0.79 to 1.36; low-certainty evidence). We pooled unadjusted data to assess postoperative total infection rates for the use of aminosalicylates (5-ASA) (OR 0.76, 95% CI 0.51 to 1.14; very low-certainty evidence). One secondary outcome examined was wound-related complications in participants using: corticosteroids (OR 1.41, 95% CI 0.72 to 2.74; very low-certainty evidence), immunomodulators (OR 1.35, 95% CI 0.96 to 1.89; very low-certainty evidence), anti-TNF agents (OR 1.18, 95% CI 0.83 to 1.68; very low-certainty evidence) and anti-integrin agents (OR 1.64, 95% CI 0.77 to 3.50; very low-certainty evidence) compared to controls. Another secondary outcome examined the odds of postoperative intra-abdominal infections in participants using: corticosteroids (OR 1.53, 95% CI 1.28 to 1.84; very low-certainty evidence), 5-ASA (OR 0.77, 95% CI 0.45 to 1.33; very low-certainty evidence), immunomodulators (OR 0.86, 95% CI 0.66 to 1.12; very low-certainty evidence), anti-TNF agents (OR 1.38, 95% CI 1.04 to 1.82; very low-certainty evidence) and anti-integrin agents (OR 0.40, 95% CI 0.14 to 1.20; very low-certainty evidence) compared to controls. Lastly we checked the odds for extra-abdominal infections in participants using: corticosteroids (OR 1.23, 95% CI 0.97 to 1.55; very low-certainty evidence), immunomodulators (OR 1.17, 95% CI 0.80 to 1.71; very low-certainty evidence), anti-TNF agents (OR 1.34, 95% CI 0.96 to 1.87; very low-certainty evidence) and anti-integrin agents (OR 1.15, 95% CI 0.43 to 3.08; very low-certainty evidence) compared to controls.

The evidence for corticosteroids, 5-ASA, immunomodulators, anti-TNF medications and anti-integrin medications was of low or very low certainty. The impact of these medications on postoperative infectious complications is uncertain and we can draw no firm conclusions about their safety in the perioperative period. Decisions on preoperative IBD medications should be tailored to each person's unique circumstances. Future studies should focus on controlling for potential confounding factors to generate higher-quality evidence.