Combined Effect Sizes and Heterogeneity
| Characteristic (Number of Trials) | Effect Size, g (95% CI) | P Valuea | Heterogeneity, I2 (95% CI) | P Valueb |
|---|---|---|---|---|
| Total (6) | 0.48 (0.18 to 0.77) | .002 | 59c (0 to 83) | |
| Outcome | ||||
| Mental health (5) | 0.56 (0.15 to 0.97) | .007 | 78d (46 to 91) | .24 |
| Quality of life (5) | 0.29 (0.11 to 0.48) | .002 | 0 (0 to 79) | |
| Intervention | ||||
| MBSR (3) | 0.53 (0.26 to 0.81) | <.001 | 0 (0 to 90) | .84 |
| MBCT (3) | 0.47 (−0.11 to 1.05) | .12 | 82d (45 to 94) | |
| Time point | ||||
| Posttest (6) | 0.45 (0.15 to 0.75) | .004 | 62c (7 to 89) | .02 |
| Follow-up <6 months (3) | 1.08 (0.73 to 1.43) | <.001 | 0 (0 to 90) | |
| Follow-up >6 months (2) | 0.13 (−0.14 to 0.39) | .35 | 0 (−) | |
| Comparison | ||||
| Active control (4) | −0.22 (−0.92 to 0.48) | .55 | 89e (75 to 95) | .01 |
| Passive control (4) | 1.22 (0.36 to 2.07) | .005 | 90e (77 to 96) | |
| Disease | ||||
| Mental (3) | 0.62 (0.02 to 1.20) | .04 | 79d (32 to 93) | .44 |
| Somatic (3) | 0.36 (0.08 to 0.63) | .01 | 13 (0 to 91) | |
| Intention-to-treat analysis | ||||
| No (3) | 0.75 (0.27 to 1.22) | .002 | 53 (0 to 86) | .059 |
| Yes (3) | 0.24 (0.01 to 0.47) | .04 | 0 (0 to 90) | |
| Study quality | ||||
| High (2) | 0.15 (−0.11 to 0.41) | .25 | 0 (−) | .01 |
| Low (4) | 0.68 (0.36 to 1.01) | <.001 | 34 (0 to 77) | |
| World region | ||||
| Europe (3) | 0.29 (0.03 to 0.54) | .03 | 31 (0 to 93) | .08 |
| Rest of the world (3) | 0.77 (0.28 to 1.25) | .002 | 46 (0 to 89) |
MBCT = mindfulness-based cognitive therapy; MBSR = mindfulness-based stress reduction.
Notes: The g value is the Hedges effect size. The I2 value is the proportion of real observed dispersion (not calculated for cells having a sample size of fewer than 3 trials).
↵a The P value associated with the effect size.
↵b The P value associated with the mixed effects contrast.
↵c P <.05.
↵d P <.01.
↵e P <.001.