Blinding in surgical randomized clinical trials in 2015

Lack of blinding in randomized clinical trials can bias the effect estimates of the observed intervention. In trials assessing nonpharmacological interventions (eg, surgical randomized clinical trials) blinding is usually more difficult. In this mini-review the blinding and reporting of blinding was assessed from surgical randomized clinical trials that were published in leading medical and surgical journals in 2015. Conducting a systematic search on PubMed, a total of 99 studies were deemed as relevant and blinding status assessed. Blinding was explicitly stated for practitioners, patients, and outcome observers in 3%, 37%, and 52%, respectively. The blinding status was not clearly stated in a large proportion of studies or had sometimes a misleading classification. Hence, authors and journals publishing randomized controlled trials should pay attention that status of blinding is unambiguously reported