Table 2

Proportion of positive, negative, and neutral abstracts in each subgroup

SubgroupSample (n)*PositiveNegativeNeutral
All included studies11553 (46.1%)22 (19.1%)50 (34.8%)
Both general and neuraxial anesthesia2612 (46.2%)7 (26.9%)7 (26.9%)
Only general anesthesia2412 (50%)7 (29.2%)5 (20.8%)
Only neuraxial anesthesia4922 (44.9%)5 (10.2%)22 (44.9%)
Hip arthroplasty2712 (44.4%)5 (18.5%)10 (37.1%)
Knee arthroplasty9241 (44.6%)19 (20.6%)32 (34.8%)
Studies with >80 patients5517 (30.9%)17 (30.9%)21 (38.2%)
Studies with <80 patients6036 (60%)5 (8%)19 (32%)
High risk of bias studies3723 (62.2%)3 (8.1%)11 (29.7%)
Low risk of bias studies7830 (38.5%)19 (24.4%)29 (37.1%)
Observational studies4015 (37.5%)11 (27.5%)14 (35%)
Randomized control trials7538 (50.7%)11 (14.7%)26 (34.6%)
  • *These subgroups are not all mutually exclusive and there may be overlap between groups.