Description:
<jats:sec><jats:title>Objective</jats:title><jats:p>To evaluate the relative risk (RR) of serious and non-serious adverse events in patients treated with exercise therapy compared with those in a non-exercising control group.</jats:p></jats:sec><jats:sec><jats:title>Design</jats:title><jats:p>Systematic review and meta-analysis.</jats:p></jats:sec><jats:sec><jats:title>Data sources</jats:title><jats:p>Primary studies were identified based on The Cochrane Database of Systematic Reviews investigating the effect of exercise therapy.</jats:p></jats:sec><jats:sec><jats:title>Eligibility criteria</jats:title><jats:p>At least two of the authors independently evaluated all identified reviews and primary studies. Randomised controlled trials were included if they compared any exercise therapy intervention with a non-exercising control. Two authors independently extracted data. The RR of serious and non-serious adverse events was estimated separately.</jats:p></jats:sec><jats:sec><jats:title>Results</jats:title><jats:p>180 Cochrane reviews were included and from these, 773 primary studies were identified. Of these, 378 studies (n=38 368 participants) reported serious adverse events and 375 studies (n=38 517 participants) reported non-serious adverse events. We found no increase in risk of serious adverse events (RR=0.96 (95%CI 0.90 to 1.02, I<jats:sup>2</jats:sup>: 0.0%) due to exercise therapy. There was, however, an increase in non-serious adverse events (RR=1.19 (95%CI 1.09 to 1.30, I<jats:sup>2</jats:sup>: 0.0%). The number needed to treat for an additional harmful outcome for non-serious adverse events was 6 [95%CI 4 to 11).</jats:p></jats:sec><jats:sec><jats:title>Conclusion</jats:title><jats:p>Participating in an exercise intervention increased the relative risk of non-serious adverse events, but not of serious adverse events. Exercise therapy may therefore be recommended as a relatively safe intervention.</jats:p><jats:p>PROSPERO registration number</jats:p><jats:p>CRD42014014819.</jats:p></jats:sec>