Motivational strategies to improve adherence to physical activity in breast cancer survivors: A systematic review and meta-analysis

Two behavioral change-based strategies for promoting adherence to physical activity (PA) suggested to have the greatest potential are the pedometer and Motivational Interviewing (MI). However, there are no comparisons between these two strategies identifying which one is more effective for improving PA adherence. This systematic review and meta-analysis aimed to determine which PA motivation strategy is more effective for promoting adherence to self-directed PA in female breast cancer survivors. Studies implementing self-directed PA which used a step tracker and/or MI for motivation in female breast cancer survivors were identified from the following databases at two timepoints, September 2019 and June 2020: CENTRAL, PubMed, CINAHL, PsycINFO, and Sportdiscuss. Sixteen randomized controlled trials (RCTs) were selected for data extraction, whereas ten RCTs were included in meta-analysis. Meta-analysis was performed on pooled data to estimate the standardized mean differences in PA duration and step count, and 95% confidence intervals. The number of participants meeting PA recommendations was also analyzed. Subgroup analysis was performed for three motivational strategies (pedometer combined with counselling, with print material or with motivational interviewing). Meta-analysis showed that pedometer combined with another intervention has a small effect on step count (p = 0.03) and a moderate effect on duration of moderate-vigorous physical activity (MVPA) (p = <0.0001) compared to controls. Additionally, motivational strategies increase the number of participants who meet a PA goal (p = 0.005). The findings of this review endorse the use of a step tracker combined with counselling, print material or MI based on behavioral change theory. This approach provided the most consistent positive effect on adherence to self-directed PA among breast cancer survivors. Future studies should evaluate differences between measures of adherence to self-directed PA, to identify the best motivation strategy for improving patient adherence and health outcomes. Systematic review registration: PROSPERO Registration number CRD42020148542