Study heterogeneity and sources of heterogeneity by meta-regression analysis of effect of physical activity in patients after treatment for cancer
| Outcomes (units or plausible ranges) | No of comparisons | Common characteristics (level) | Heterogeneity | Multivariable meta-regression* | ||||
|---|---|---|---|---|---|---|---|---|
| I2 (%) | P value | Source of heterogeneity [confounder] | Estimate (95% CI) | P value | ||||
| Psychological outcomes | ||||||||
| FACT-fatigue (0-52) | 824 29 31 55 56 68 | — | 0 | 0.86 | — | — | — | |
| PFS-fatigue (0-10) | 365 69 | Publication year (2007); cancer type (breast) | 0 | 0.64 | — | — | — | |
| EORTC-fatigue (0-100) | 257 60 | Quality (+) | 75 | 0.05 | Any one of sources except quality† | — | — | |
| BDI (0-63) | 424 28 53 65 | Physical activity (aerobic); sex (female) | 47 | 0.13 | — | — | — | |
| HADS-depression (0-21) | 226 60 | Quality (+) | 76 | 0.04 | Any one of sources except quality† | — | — | |
| HADS-anxiety (0-21) | 226 60 | Quality (+) | 78 | 0.03 | Any one of sources except quality† | — | — | |
| POMS-total mood disturbance | 258 63 | — | 53 | 0.15 | — | — | — | |
| Quality of life outcomes | ||||||||
| EORTC: | ||||||||
| Physical function (0-100) | 257 60 | Quality (+) | 0 | 0.49 | — | — | — | |
| Emotional function (0-100) | 357 60 63 | — | 77 | 0.01 | Quality: + v – [study size] | −17.4 (−28.9 to −5.8) [−0.22 (−0.37 to −0.06)] | 0.003 [0.006] | |
| Total (0-100) | 357 60 63 | — | 70 | 0.04 | Quality: + v – [study size] | −16.5 (−29.2 to −3.8) [−0.18 (−0.34 to −0.08)] | 0.01 [0.03] | |
| FACT: | ||||||||
| Physical wellbeing (0-28) | 624 55 56 65 72 76 | Quality (+) | 92 | <0.001 | Aerobic + resistance v aerobic | 8.4 (6.3 to 10.5) | <0.001 | |
| Emotional wellbeing (0-24) | 624 55 56 65 72 76 | Quality (+) | 61 | 0.03 | Aerobic + resistance v aerobic | 2.8 (0.9 to 4.7) | 0.01 | |
| Social/family wellbeing (0-28) | 624 55 56 65 72 76 | Quality (+) | 15 | 0.32 | — | — | — | |
| Functional wellbeing (0-28) | 624 55 56 65 72 76 | Quality (+) | 93 | <0.001 | Aerobic + resistance v aerobic | 9.6 (7.1 to 12.1) | <0.001 | |
| Breast (0-36) | 455 65 72 76 | Quality (+); cancer type (breast) | 78 | 0.003 | Aerobic + resistance v aerobic | 5.3 (1.9 to 8.7) | 0.002 | |
| Treatment duration [age] | −0.8 (−1.4 to −0.1) [−0.7 (−1.3 to −0.1)] | 0.02 [0.03] | ||||||
| Breast total (0-140) | 1023 55 59 65 68 72 76 | Cancer type (breast) | 86 | <0.001 | Aerobic + resistance v aerobic | 24.4 (17.9 to 30.9) | <0.001 | |
| Colorectal total (0-136) | 329 31 56 | Cancer type (colorectal) | 0 | 0.72 | — | — | — | |
| General total (0-108) | 724 55 56 65 66 72 76 | — | 92 | <0.001 | Aerobic + resistance v aerobic | 22.1 (16.7 to 27.4) | <0.001 | |
| SF-36: | ||||||||
| Physical function (0-100) | 240 62 | — | 0.0 | 0.51 | — | — | — | |
| Role physical (0-100) | 240 62 | — | 56 | 0.13 | — | — | — | |
| Bodily pain (0-100) | 240 62 | — | 54 | 0.14 | — | — | — | |
| General health (0-100) | 240 62 | — | 76 | 0.04 | Any one of sources† | — | — | |
| Vitality (0-100) | 240 62 | — | 0 | 0.82 | — | — | — | |
| Social function (0-100) | 240 62 | — | 0 | 0.45 | — | — | — | |
| Role emotion (0-100) | 240 62 | — | 0 | 0.82 | — | — | — | |
| Mental health (0-100) | 240,62 | — | 0 | 0.64 | — | — | — | |
| SF physical component scale (0-100)‡ | 459 73 78 | — | 55 | 0.09 | Age | −0.9 (−1.8 to −0.04) | 0.04 | |
| SF mental component scale (0-100)†‡ | 459 73 78 | — | 39 | 0.18 | — | — | — | |
BDI=Beck depression inventory; EORTC=European Organization for Research and Treatment of Cancer; FACT=functional assessment of cancer therapy; HADS=hospital anxiety and depression scale; PFS=revised Piper fatigue scale; POMS=profile of mood states; SF-36=short form-36.
*Values in square brackets correspond to those confounders.
†As there were only two studies.
‡Two studies used SF-36 and one used SF-12.