Periodic email prompts to re-use an internet-delivered computer-tailored lifestyle program: Influence of prompt content and timing

Background: adherence to internet-delivered lifestyle interventions using multiple tailoring is suboptimal. therefore,it is essential to invest in proactive strategies,such as periodic email prompts,to boost re-use of the intervention. objective: this study investigated the influence of content and timing of a single email prompt on re-use of an internet-delivered computer-tailored (ct) lifestyle program. methods: a sample of municipality employees was invited to participate in the program. all participants who decided to use the program received an email prompting them to revisit the program. a 2×3 (content × timing) design was used to test manipulations of prompt content and timing. depending on the study group participants were randomly assigned to,they received either a prompt containing standard content (an invitation to revisit the program),or standard content plus a preview of new content placed on the program website. participants received this prompt after 2,4,or 6 weeks. in addition to these 6 experimental conditions,a control condition was included consisting of participants who did not receive an additional email prompt. clicks on the uniform resource locator (url) provided in the prompt and log-ins to the ct program were objectively monitored. logistic regression analyses were conducted to determine whether prompt content and/or prompt timing predicted clicking on the url and logging in to the ct program. results: of all program users (n=240),206 participants received a subsequent email prompting them to revisit the program. a total of 53 participants (25.7%) who received a prompt reacted to this prompt by clicking on the url,and 25 participants (12.1%) actually logged in to the program. there was a main effect of prompt timing; participants receiving an email prompt 2 weeks after their first visit clicked on the url significantly more often compared with participants that received the prompt after 4 weeks (odds ratio [or] 3.069,95% ci 1.392-6.765,p=.005) and after 6 weeks (or 4.471,95% ci 1.909-10.471,p=.001). furthermore,participants who received an email prompt 2 weeks after their first visit logged in to the program significantly more often compared to participants receiving the prompt after 6 weeks (or 16.356,95% ci 2.071-129.196,p=.008). a trend was observed with regard to prompt content. participants receiving a prompt with additional content were more likely to log in to the program compared to participants who received a standard prompt. however,this result was not statistically significant (or 2.286,95% ci 0.892-5.856,p=.09). conclusions: the key findings suggest that boosting revisits to a ct program benefits most from relatively short prompt timing. furthermore,a preview of new website content may be added to a standard prompt to further increase its effectiveness in persuading people to log in to the program. © filippo castiglione.