Risk of Bias
More than half of domains of risk of bias were high or
unclear across studies (Table 3). Selection bias was low or
unclear across studies as they used random sequences for
randomization (86%) while limited information was provided
to assess allocation concealment (71%). Since most
studies used a wait-list or usual care control group (71%),
participants and study personnel were often not blinded. This
could result in a high risk of performance and detection bias.
Some of the studies (42.9%) did not conduct intent-to treat
data analysis, which is associated with attrition bias. Most
studies reported all pre-specified outcomes except two studies
(28.6%) that did not report on some of the subjective outcomes.