Table 3.
Secondary analyses. Data are outcome measure (95% credible interval) unless stated otherwise
| No of meta-analyses, trials | ROR | Ф | ĸ | |
|---|---|---|---|---|
| Lack of double blinding or unclear double blinding (v double blind) | ||||
| All outcomes | 94, 722 | 0.99 (0.86 to1.09) | 0.07 (0.01 to 0.29) | 0.06 (0.01 to 0.18) |
| Benefit | 74, 583 | 1.02 (0.90 to 1.13) | 0.06 (0.01 to 0.27) | 0.07 (0.01 to 0.19) |
| Harms | 20, 139 | 0.64 (0.38 to 1.04) | 0.15 (0.01 to 0.89) | 0.13 (0.01 to 1.23) |
| Observer reported outcomes: benefit | 36, 374 | 1.04 (0.84 to 1.25) | 0.14 (0.01 to 0.57) | 0.08 (0.01 to 0.23) |
| Subjectively assessed observer reported outcomes: benefit | 27, 221 | 1.11 (0.86 to 1.44) | 0.13 (0.01 to 0.61) | 0.09 (0.01 to 0.42) |
| Patient reported outcomes: benefit | 13, 53 | 0.89 (0.57 to 1.40) | 0.15 (0.01 to 0.83) | 0.12 (0.01 to 0.88) |
| Healthcare provider decision outcomes: benefit | 24, 147 | 0.98 (0.79 to 1.19) | 0.07 (0.01 to 0.31) | 0.07 (0.01 to 0.36) |
| Repeat of the main analyses excluding trials with unclear blinding status | ||||
| (Ia) Effect of blinding patients in trials with patient reported outcomes | 16, 116 | 1.10 (0.72 to 1.69) | 0.19 (0.02 to 0.76) | 0.23 (0.02 to 0.61) |
| (Ib) Effect of blinding patients in trials with blinded observer reported outcomes | 14, 94 | 1.00 (0.70 to 1.44) | 0.11 (0.01 to 0.58) | 0.10 (0.01 to 0.60) |
| (IIa) Effect of blinding healthcare providers in trials with healthcare provider decision outcomes | 28, 160 | 0.97 (0.77 to 1.18) | 0.08 (0.01 to 0.36) | 0.07 (0.01 to 0.39) |
| (IIb) Effect of blinding healthcare providers in trials with blinded observers/patients assessing the outcome | 13, 90 | 0.96 (0.64 to 1.45) | 0.14 (0.01 to 0.82) | 0.10 (0.01 to 0.68) |
| (III) Effect of blinding outcome assessors (that is, observers) in trials with subjective outcomes | 43, 365 | 1.01 (0.85 to 1.20) | 0.11 (0.01 to 0.35) | 0.06 (0.01 to 0.25) |
| Main analysis by type of outcome | ||||
| (III) Effect of blinding outcome assessors (that is, observers) in trials with subjective outcomes: continuous* | 14, 108 | dSMD 0.02 (−0.22 to 0.26) | 0.07 (0.01 to 0.37) | 0.07 (0.01 to 0.31) |
| (III) Effect of blinding outcome assessors (that is, observers) in trials with subjective outcomes: binary* | 32, 289 | 1.01 (0.85 to 1.20) | 0.11 (0.01 to 0.37) | 0.06 (0.01 to 0.23) |
| Main analyses by type of control intervention | ||||
| (III) Effect of blinding outcome assessors (that is, observers) in trials with subjective outcomes: active control* | 12, 61 | 1.01 (0.64 to 1.55) | 0.12 (0.01 to 0.70) | 0.10 (0.01 to 0.56) |
| (III) Effect of blinding outcome assessors (that is, observers) in trials with subjective outcomes: inactive control (placebo/no treatment/standard care)* | 34, 336 | 1.01 (0.85 to 1.21) | 0.10 (0.01 to 0.36) | 0.06 (0.01 to 0.23) |
| Inadequate (or unclear) concealment of the allocation sequence (v adequate) | ||||
| (Ia) Effect of blinding patients in trials with patient reported outcomes† | 13, 116 | 0.95 (0.68 to1.29) | 0.11 (0.01 to0.63) | 0.10 (0.01 to0.51) |
| (IIa) Effect of blinding healthcare providers in trials with healthcare provider decision outcomes† | 22, 154 | 0.90 (0.72 to1.12) | 0.09 (0.01 to0.35) | 0.07 (0.01 to0.32) |
| (III) Effect of blinding outcome assessors (that is, observers) in trials with subjective outcomes† | 40, 349 | 0.88 (0.76 to1.02) | 0.07 (0.01 to0.27) | 0.08 (0.01 to0.30) |
ROR=ratio of odds ratios; ĸ=standard deviation increase in heterogeneity between trials; Ф=standard deviation in mean bias between meta-analyses; dSMD=difference in standardised mean difference.
*
The prespecified minimum of 10 meta-analyses for analysis to be feasible was met only in analysis III.
†
Analyses include meta-analyses from each of the datasets used in the main analyses that were informative for the impact of inadequate (or unclear) concealment of the allocation sequence. The numbers of informative meta-analyses in analyses Ib and IIb did not meet the prespecified minimum of 10 meta-analyses for analysis to be feasible.