Instruments assessing risk of bias of randomized trials frequently included items that are not addressing risk of bias issues.

OBJECTIVES: To establish whether items included in instruments published in the last decade assessing risk of bias of randomized controlled trials (RCTs) are indeed addressing risk of bias. STUDY DESIGN AND SETTING: We searched Medline, Embase, Web of Science, and Scopus from 2010 to October 2021 for instruments assessing risk of bias of RCTs. By extracting items and summarizing their essential content, we generated an item list. Items that two reviewers agreed clearly did not address risk of bias were excluded. We included the remaining items in a survey in which 13 experts judged the issue each item is addressing: risk of bias, applicability, random error, reporting quality, or none of the above. RESULTS: Seventeen eligible instruments included 127 unique items. After excluding 61 items deemed as clearly not addressing risk of bias, the item classification survey included 66 items, of which the majority of respondents deemed 20 items (30.3%) as addressing risk of bias; the majority deemed 11 (16.7%) as not addressing risk of bias; and there proved substantial disagreement for 35 (53.0%) items. CONCLUSION: Existing risk of bias instruments frequently include items that do not address risk of bias. For many items, experts disagree on whether or not they are addressing risk of bias.

The association between stage of treatment-resistant depression and clinical utility of ketamine/esketamine: A systematic review.

OBJECTIVE: Ketamine has demonstrated rapid and significant antidepressant effects in patients with treatment resistant depression (TRD). Herein, we conducted a systematic review to determine ketamine's efficacy as a function of the stage of treatment resistance (e.g., number of failed treatments) among individuals with TRD. METHODS: A systematic search of PubMed and Scopus from inception to August 2021 was conducted. Where applicable, the studies were categorized into low and high stages of resistance, where low category included studies where the mean number of failed antidepressants was <3 or had a higher proportion of subjects with ≤2 antidepressant trials. Reported indicators of treatment resistance and efficacy were extracted from randomized-controlled trials (RCTs) assessing ketamine or esketamine for TRD. RESULTS: In total, 18 RCTs were included in the current review. There was variability across reported indicators of disease severity, definition of treatment resistance, as well as treatment protocols, preventing clear direct and indirect comparison of relative efficacy of ketamine at different stages of treatment resistance. Ketamine was effective in reducing depressive symptoms in RCTs at both lower and higher stages of treatment resistance; however, the effect size and duration of effects was greater in RCTs of lower stage of treatment resistance. CONCLUSIONS: Our findings suggested that ketamine has antidepressant efficacy across all identified stages of treatment resistance, however with increasing failed treatment trials, treatment might be less efficacious. At this time, the comparative efficacy as a function of resistance stage remains to be well-established. Evaluation of participant level data is required to more clearly determine the association between level of treatment resistance and likelihood of response.