Journal of Rehabilitation Medicine 51-3 | Page 11

Objective feedback on physical activity in healthcare interventions study. The study focused on patients of healthcare institutions, who were mostly patients with (chronic) neurological or cardiovascular diseases. These patients may experience more barriers to increasing their PA compared with healthy individuals (6). In addition, participants in the current study were slightly older (mostly around 65 years of age) compared with other studies. It is possible that older individuals increase their PA less because they experience difficulty using new technologies, such as activity monitors, to increase PA. Nevertheless, the overall positive results suggest that using wearable technology is also a promising tool to promote PA in healthcare settings. Similar to other reviews (14, 16), large heterogeneity was found in the study characteristics. However, after excluding 2 studies based on leave-one-out sensitivity analyses, heterogeneity was acceptable. Mediating effects of study characteristics (setting, duration and population) were explored by calculation of pooled SMDs of grouped characteristics (Table III). Regarding intervention setting, the effect sizes of studies were smaller in an inpatient setting compared with home- based interventions, suggesting that the difference between the intervention and control groups is smaller when both groups are situated in an inpatient setting, as stated by Dorsch et al. (28), who found comparable results. It can be assumed that both the intervention and control groups in inpatient populations were more dedicated to a strict treatment schedule. Thus, the chance that behaviour of both the control and interven- tion groups was similar was higher compared with an outpatient- or home-based setting. In other words, a free-living environment allows more voluntary phy- sical behaviour. This statement may also explain the difference in magnitude of the overall effect in the current study (0.34) in comparison with, for example, the overall effect in the meta-analysis by Kang et al. (20) amongst mostly healthy and younger free-living populations (0.68). Analysis of intervention duration in the current study agreed with the study of Goode et al. (17), since shorter intervention durations showed larger effects on PA compared with longer-lasting interventions. SMD calculation in the current study was based on post-intervention measurements. Adherence to use of wearables for a longer time in daily life may be more difficult, and thus the chance of relapsing to previous behaviour is higher. Future studies should include more follow-up measurements to examine the sustainability of behaviour change due to these interventions. The frequency of applying different intervention strategies was explored in this study and the results em- phasize the importance of combining objective PA feed- back with BCT strategies (Table II). All interventions 157 included in this review were combined with multiple BCT components (Tables I and II), assuming that re- searchers find BCT a substantial element for designing RCTs for promotion of PA in healthcare. In addition, Nolan et al. (26) explained the lack of improvement in PA by the low levels of added behavioural counselling. Nevertheless, BCT is an umbrella construct, and the BCT components in the studies included in the current review varied considerably. Not all studies described the content of the BCT sufficiently in the intervention and control groups, hence BCT could only be assessed approximately. Therefore, only careful suggestions for effect directions could be drawn regarding specific BCT components. Goal-setting, education and barrier identification are factors that are probably important, since they were often present in interventions with a relatively large positive effect size. Nevertheless, in 12 of the 14 included studies, the control group received usual care, and it can be assumed that, in most cases, BCT was also present in usual care. As Hakala et al. (16) have suggested previously; the effect size is influenced by the load of the control treatment. With respect to the current study, this could mean that the magnitude of the effect is relatively small because of the amount of BCT that is already present in usual care, and thereby also in control groups. Study limitations First, due to the heterogeneity in intervention strategies and treatments of control groups, the specific effect of the objective PA feedback component could not be determined. Furthermore, the SMDs of PA were calculated based on post-intervention measurements assuming that the RCTs in this meta-analysis included an ac- ceptable randomization procedure. However, baseline comparison of PA was often not taken into account in randomization procedures. Therefore, intervention and control groups may have differed in baseline PA, which might have influenced the results. Future studies should compare the intervention and control group based on mean changes between pre- and post-measurements. Another methodological limitation in the current meta- analysis concerns comparison of the intervention ef- fects based on SMD. In the included studies, the SMDs were calculated using diverse PA outcome measures and generated by different methods of data-processing using various devices. These methodological differen- ces between studies in accelerometer data-processing limit comparability (36). Using a standardized version of the effect size, such as the SMD, only partly resol- ves the problem of comparing different PA outcomes measured using different devices. J Rehabil Med 51, 2019