Overall Methodological Quality of the Included Studies
The distribution of AMSTAR scores for includeed studies pubished between the years 2000 – 2020 had a mean (SD) of 6.75 ±1.6 (Figure 2A). Adherence to each specific AMSTAR criteria was inconistent across included studies (Figure 2B).The top three most reported AMSTAR criteria included the assessment of the quality of included studies in the systematic review (Criterion 7: n=45 (94%)), the inclusion of the characteristics of the included studies (Criterion 6: n=44 (92%)), and a tie between an a priori design being provided and appropriate methods used to pool studies in a meta-analysis (Criterion 1 & 9: n=40 (83%)). The AMSTAR criteria that were least frequently reported involved the inclusion of grey literature (Item 4: n=3 (6%)), the assessment of publication bias (Item 10: n=6 (13%)), and the performance of a comprehensive literature search (Item 3: n=18 (38%)). The overall methodological quality was variable with scores from 3/11 (n=2) to 9/11 (n=7).