Side effects are incompletely reported among systematic reviews in gastroenterology

Systematic reviews are an integral component of evidence-based health care. However, little is known on how well they report the potential harms of interventions. We assessed the reporting of harms in recently published systematic reviews of interventions relevant to clinical gastroenterology.

We identified all systematic reviews of randomized trials of gastroenterology interventions published from 2008 to 2012 in highly cited gastroenterology and general medical journals. We adapted the Consolidated Standards of Reporting Trials guidelines for harms and assessed qualitative and quantitative parameters of harms reporting. Regression analyses determined predictors of more comprehensive harms reporting.

In total, 78 systematic reviews were identified, with 72 published in gastroenterology journals and six in general medical journals. Overall, one in three systematic reviews (26/78, 33%) did not refer to harms of the intervention anywhere in the article. Less than half of the studies included adverse events as an outcome measure, and data on absolute rates of adverse events were only provided in 28%. Most (65%) did not include any figures or tables on adverse event; however, all included these on efficacy outcomes (mean, 3 and range, 1-7). Regression analyses indicated that the use of reporting guidelines was significantly associated with better harms reporting (P = 0.04).

The reporting of harms in gastroenterology systematic reviews is largely inadequate and highly asymmetrical compared with the reporting of benefits. We suggest that review authors routinely assess both efficacy and harms outcomes of an intervention and that reporting guidelines specifically targeting harms reporting be developed.