Understanding of Blinding and its Reporting in Randomized Controlled Trials

To generate reliable evidence regarding public health care/ clinical practice, a well-designed randomized controlled trial (RCT) is the ultimate answer for assessing the efficacy of a newly proposed intervention/ drug and/ or to identify more efficacious interventions/drugs regarding any of the health problems. In such RCTs, to avoid known as well as unknown biases, the role of random allocation (i.e., randomization) of considered patients in different intervention/ drug arms is already discussed in another continuing medical education (CME) published in the previous issue of this journal. In spite of avoiding allocation bias in every RCT, one may also avoid intentional/ unintentional bias through blinding to strengthen the credentials of observed findings further. To be more specific, if feasible, study participants and/ or researchers/ observers/ outcome assessors and/ or data analysts in an RCT need not be aware of the specific intervention/ drug being received by study participants in various arms and keeping in view of feasibility, one of the various types of blinding (e.g., single; double; triple) may be used. Further, recently reviews of reported RCTs have documented incomplete as well as inaccurate reporting of blinding in the articles. The present write-up therefore addresses important issues related to possible blinding under RCT, its type & method, and its reporting in the reports/ articles.