Identification of dropout predictors to a community-based physical activity programme that uses motivational interviewing

Background: Participant dropout reduces intervention effectiveness. Predicting dropout has been investigated for Exercise Referral Schemes (ERSs), but not physical activity (PA) interventions with Motivational Interviewing (MI). Methods: Data from attendees (n=619) to a community-based PA programme utilising MI techniques was analysed using chi-squared to determine dropout and attendance group differences. Binary logistic regression investigated the likelihood of dropout before 12-weeks. Results: 44.7% dropped out, with statistical (P<0.05) differences between groups for age, PA, and disability. Regression for each variable showed participants aged 61-70 years (OR=0.28, CI=0.09 to 0.79; P=0.018), >70 years (OR=0.30, CI=0.09 to 0.90; P=0.036), and HEPA (OR=0.40, CI=0.20 to 0.75; P=0.006) reduced dropout likelihood. Endocrine system disorders (OR=4.24, CI=1.19 to 19.43; P=0.036) and musculoskeletal disorders (OR=3.14, CI=1.84 to 5.45; P<0.001) increased dropout. Significant variables were combined in a single regression model. Dropout significantly reduced for 61-70 year olds (OR=0.31, CI=0.10 to 0.90; P=0.035), and HEPA (OR=0.39, CI=0.19 to 0.76; P=0.008). Musculoskeletal disorders increased dropout (OR=2.67, CI=1.53 to 4.75; P<0.001). Conclusions: Age, PA, and disability type significantly influence dropout at 12-weeks, the first results specific to MI based programmes indicating the inclusion of MI and highlight the need for further research.