JMIR Publications

ABSTRACT

Background:

Despite many advantages of web-based health behavior interventions such as wide accessibility or low costs, these interventions are often accompanied by high attrition rates, particularly in usage under real-life conditions. It would therefore be helpful to implement strategies such as the use of financial incentives to motivate program participation and increase adherence.

Objective:

This ecological study examined program adherence to a 12-week web-based physical activity (PA) intervention (Fitness Coach) among insurants who participated in an additional incentive program (IP group) and those who did not use the incentive program (No IP group). IP users had the perspective of receiving 30 € cash back at the end of the intervention.

Methods:

Registration and usage data of the Fitness Coach were analyzed between September 2016 and June 2018. Depending on the duration of use and the weekly recording of tasks, four adherence groups (low, occasional, strong, complete adherence) were defined. Demographic characteristics were collected by a self-reported questionnaire at registration. We analyzed baseline predictors and moderators of complete adherence such as participation in the IP, age, gender, and BMI using binary logistic regressions.

Results:

A total of 18.613 eligible persons registered for the intervention with 15.482 users choosing to participate in the incentive program (IP; Mage = 42.4 years; MBMI = 24.5 kg/m2; 65.1% female) and 3.131 users deciding not to use the incentive program (No IP; Mage = 40.7 years; MBMI = 26.2 kg/m2; 72.2% female). At the end of the intervention, participants of the IP group showed 4.8 times higher complete adherence rates than the No IP group (39.2% vs 8.1%), also yielding significantly higher odds to complete the intervention (Odds Ratio [OR] = 12.638) for the IP users. Gender significantly moderated the effect with men in the IP group showing higher odds to be completely adherent than women overall and men in the No IP group (OR = 1.761). Furthermore, older age, as well as male gender were significant predictors of complete adherence for all participants whereas BMI did not predict intervention completion.

Conclusions:

A total of 18.613 eligible persons registered for the intervention with 15.482 users choosing to participate in the incentive program (IP; Mage = 42.4 years; MBMI = 24.5 kg/m2; 65.1% female) and 3.131 users deciding not to use the incentive program (No IP; Mage = 40.7 years; MBMI = 26.2 kg/m2; 72.2% female). At the end of the intervention, participants of the IP group showed 4.8 times higher complete adherence rates than the No IP group (39.2% vs 8.1%), also yielding significantly higher odds to complete the intervention (Odds Ratio [OR] = 12.638) for the IP users. Gender significantly moderated the effect with men in the IP group showing higher odds to be completely adherent than women overall and men in the No IP group (OR = 1.761). Furthermore, older age, as well as male gender were significant predictors of complete adherence for all participants whereas BMI did not predict intervention completion.