Table 3

 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 comparisonsCommon characteristics (level)HeterogeneityMultivariable meta-regression*
I2 (%)P valueSource of heterogeneity [confounder]Estimate (95% CI)P value
Psychological outcomes
FACT-fatigue (0-52)824 29 31 55 56 6800.86
PFS-fatigue (0-10)365 69Publication year (2007); cancer type (breast)00.64
EORTC-fatigue (0-100)257 60Quality (+)750.05Any one of sources except quality†
BDI (0-63)424 28 53 65Physical activity (aerobic); sex (female)470.13
HADS-depression (0-21)226 60Quality (+)760.04Any one of sources except quality†
HADS-anxiety (0-21)226 60Quality (+)780.03Any one of sources except quality†
POMS-total mood disturbance 258 63530.15
Quality of life outcomes
EORTC:
 Physical function (0-100)257 60Quality (+)00.49
 Emotional function (0-100)357 60 63770.01Quality: + 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 63700.04Quality: + 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 76Quality (+)92<0.001Aerobic + resistance v aerobic8.4 (6.3 to 10.5)<0.001
 Emotional wellbeing (0-24)624 55 56 65 72 76Quality (+)610.03Aerobic + resistance v aerobic2.8 (0.9 to 4.7)0.01
 Social/family wellbeing (0-28)624 55 56 65 72 76Quality (+)150.32
 Functional wellbeing (0-28) 624 55 56 65 72 76Quality (+)93<0.001Aerobic + resistance v aerobic9.6 (7.1 to 12.1)<0.001
 Breast (0-36)455 65 72 76Quality (+); cancer type (breast)780.003Aerobic + resistance v aerobic5.3 (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 76Cancer type (breast)86<0.001Aerobic + resistance v aerobic24.4 (17.9 to 30.9)<0.001
 Colorectal total (0-136)329 31 56Cancer type (colorectal)00.72
 General total (0-108)724 55 56 65 66 72 7692<0.001Aerobic + resistance v aerobic22.1 (16.7 to 27.4)<0.001
SF-36:
 Physical function (0-100)240 620.00.51
 Role physical (0-100)240 62560.13
 Bodily pain (0-100)240 62540.14
 General health (0-100)240 62760.04Any one of sources†
 Vitality (0-100)240 6200.82
 Social function (0-100)240 6200.45
 Role emotion (0-100)240 6200.82
 Mental health (0-100)240,6200.64
SF physical component scale (0-100)‡459 73 78550.09Age−0.9 (−1.8 to −0.04)0.04
SF mental component scale (0-100)†‡459 73 78390.18

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.