A Cluster-Randomized Trial on Small Incentives to Promote Physical Activity

Introduction: There has been limited research investigating whether small financial incentives can promote participation, behaviour change, and engagement in physical activity promotion programs. This study evaluates the effects of two types of small financial incentives within a physical activity promotion program of a Swiss health insurance company.
Study Design: Three-arm cluster-randomized trial comparing small personal financial incentives and charity financial incentives (10 Swiss Francs, equal to $10.4) for each month with an average step count of at least 10,000 steps per day) to control. Insurees' federal state of residence was the unit of randomization. We collected data in 2015 and completed the analyses in 2018.
Setting/participants: We invited German-speaking insurees of a large health insurer in Switzerland. Invited insurees were aged ≥ 18 years, enrolled in complementary insurance plans and registered on the insurer's online platform.
Main outcome measures: Primary outcome was the participation rate. Secondary outcomes were steps per day, participant days that more than 10,000 steps were achieved and non-usage attrition over the first three months of the program.
Results: Participation rate was 5.94% in the personal financial incentive group (OR: 1.96; 95% CI: 1.55 to 2.49) and 4.98% in the charity financial incentive group (OR: 1.59; 95% CI: 1.25 to 2.01) compared to 3.23% in the control group. At the start of the program, the charity financial group had a 12% higher chance to walk 10,000 steps per day than the control group (OR: 1.68; 95% CI: 1.23 to 2.30), but this effect dissipated after three months. Steps per day and non-usage attrition did not differ significantly between the groups.
Conclusions: Small personal and charity financial incentives can increase participation in physical activity promotion programs. Incentives may need to be modified in order to prevent attrition and promote behaviour change over a longer period of time.