The influence of bias in randomized controlled trials on rehabilitation intervention effect estimates: what we have learned from meta-epidemiological studies.

The review found only a small number of rehabilitation studies, and the included studies were exploratory, underpowered, and heterogeneous, so no definitive conclusion could be drawn. The search was narrow and only published English reports were included, so relevant studies may have been missed. The included studies did not assess their own risk of bias, and they included randomized trials of any methodological quality. Definitions of attrition bias and intention-to-treat analysis varied across studies, and one study found overestimation while another found underestimation. Most interventions were physical therapy or exercise, with little information about controls or outcome measurements, limiting generalizability to other rehabilitation interventions. The review did not examine interactions between different biases or other biases such as publication bias and outcome measurement bias. The included studies did not meet recommended sample size standards for adequate power.

The authors certified that there is no conflict of interest with any financial organization regarding the material discussed in the manuscript.