Table 3

Metaregression

Covariate*‡‡Coefficient (95% CI)P valueR2 analogue
Model 0
 Intercept−0.128 (-0.34 to 0.084)0.2370.57
 Goals and planning0.05 (-0.041 to 0.141)0.281
 Text messaging0.365 (0.107 to 0.624) 0.006
 Personalisation0.252 (0.033 to 0.47) 0.024
 Conflicts of interest0.072 (-0.222 to 0.366)0.631
 Graded tasks−0.132 (-0.424 to 0.159)0.374
 Behaviour change theories0.24 (-0.004 to 0.484)0.054
Model 1
 Intercept−1.054 (-1.875 to -0.232) 0.012 0.67
 Text messaging0.302 (0.112 to 0.492) 0.002
 Personalisation0.365 (0.16 to 0.57) 0.001
 Number of BCTs in the intervention0.02 (-0.007 to 0.047)0.151
 Retention in the intervention0.011 (0.002 to 0.02) 0.021
Model 2
 Intercept−1.081 (-1.914 to -0.248) 0.011 0.64
 Text messaging0.334 (0.147 to 0.522) 0.001
 Personalisation0.427 (0.236 to 0.619) <0.001
 Retention rate in the intervention0.012 (0.004 to 0.02) 0.006
Model 3
 Intercept−1.058 (-1.925 to -0.19) 0.017 0.64
 Text messaging0.32 (0.127 to 0.512) 0.001
 Personalisation0.445 (0.252 to 0.639) <0.001
 Retention rate in the intervention0.013 (0.004 to 0.022) 0.005
 Study duration−0.007 (-0.019 to 0.004)0.192
Model 4
 Intercept−2.077 (-3.395 to -0.759) 0.002 0.71
 Text messaging0.422 (0.222 to 0.623) <0.001
 Personalisation0.49 (0.293 to 0.686) <0.001
 Retention rate in the intervention0.022 (0.009 to 0.036) 0.001
 Studies where the app or tracker was the only difference between intervention and control0.374 (-0.005 to 0.752)0.053

  • Multivariate metaregression models with statistically significant moderators identified in subgroup analyses, a dichotomous variable representing studies where the app or tracker was the only difference between intervention and control, and continuous moderators (number of BCTs in the intervention, retention rate and study duration). Statistically significant moderators were kept in successive models. R2 was calculated to determine the proportion of total between-study variance explained by the model.

  • Italicised numbers correspond to statistically significant p values.

  • *Goals and planning: studies where the intervention includes BCTs in this category.

  • †Text messaging: studies where the intervention includes text messaging.

  • ‡Personalisation: studies mentioning personalisation in the intervention.

  • §Conflicts of interest: studies where the authors mention conflicts of interest.

  • ¶Graded tasks: studies where the intervention included this BCT.

  • **Behaviour change theories: studies mentioning use of behaviour change theories.

  • ††Reference for all dichotomous variables: remaining studies.

  • ‡‡Retention rate: retention rate in the intervention group (continuous variable).

  • BCT, behaviour change technique.