Heterogeneity of effect estimates for trials assessing the effect of exercise for patients diagnosed with depression explored by comparing subgroups
| Subgroups | Number of trials (participants) | Random-effects meta-analysis SMD (95% CI, p, I2) | Subgroup explains heterogeneity p Value |
| Risk of bias | |||
| Less than high risk of bias1 | 4 (530) | −0.11 (−0.41 to 0.18; p=0.45; I2=62%) | <0.001 |
| High risk of bias | 31 (1968) | −0.75 (−0.98 to −0.52; p<0.001; I2=81%) | |
| Age | |||
| Old (>59 years) | 5 (492) | −0.77 (−1.34 to −0.19; p=0.009; I2=87%) | 0.78 |
| Young (<59 years) | 30 (2006) | −0.68 (−0.90 to −0.45; p<0.001; I2=83%) | |
| Exercise context | |||
| Group exercise | 26 (1785) | −0.75 (−1.01 to −0.50; p<0.001; I2=83%) | 0.30 |
| Individual exercise | 9 (713) | −0.52 (−0.88 to −0.16; p=0.005; I2=73%) | |
| Duration | |||
| <10 weeks | 15 (721) | −0.92 (−1.09 to −0.74; p<0.001; I2=14%) | 0.007 |
| 10 weeks or more | 20 (1777) | −0.49 (−0.75 to −0.23; p<0.001; I2=83%) | |
| Attention control | |||
| Attention control | 10 (733) | −0.56 (−0.98 to −0.15; p=0.008; I2=85%) | 0.91 |
| Waitlist | 2 (47) | −0.67 (−2.48 to 1.13; p=0.47; I2=88%) | |
| Pharmacotherapy | |||
| Add-on | 11 (734) | −0.92 (−1.38 to −0.46; p<0.001; I2=86%) | 0.82 |
| No medication | 6 (318) | −0.82 (−1.58 to −0.06; p=0.03; I2=88%) | |
| Somatic comorbidity | |||
| Somatic comorbidity | 0 | N/A | |
| No comorbidity | 35 (2331) | N/A | |
| Minor depression | |||
| Including minor depression | 6 (350) | −0.90 (−1.65 to −0.15; p=0.02; I2=86%) | 0.53 |
| No minor depression | 25 (2148) | −0.65 (−0.87 to −0.43; p<0.001; I2=81%) | |
| Patient setting | |||
| Inpatients | 10 (549) | −0.88 (−1.07 to −0.70; p<0.001; I2=6%) | 0.07 |
| Outpatients | 21 (1782) | −0.60 (−0.85 to −0.35; p<0.001; I2=83%) | |
| Trial size | |||
| Trials n≤50 | 18 (578) | −1.11 (−1.52 to −0.72; p<0.001; I2=78%) | 0.001 |
| Trials n>50 | 17 (1920) | −0.37 (−0.57 to −0.18; p<0.001; I2=75%) | |
| Increase in exercise capacity | |||
| VO2max>2.8 mL/kg/min | 5 (340) | −0.48 (−1.08 to 0.13; p=0.12; I2=86%) | 0.65 |
| VO2max≤2.8 mL/kg/min | 6 (661) | −0.32 (−0.61 to 0.02; p=0.03; I2=68%) |
VO2max, maximal oxygen uptake.