The National Diabetes Prevention Program (National DPP) is a partnership of public and private organizations working together to build a nationwide infrastructure to deliver a lifestyle change program proven to prevent or delay onset of type 2 diabetes in adults with prediabetes. Much variability exists in the number of days participants stay in the 12-month program. Of the 217,585 eligible participants enrolled in in-person and online organizations as of October 2019, the average length of stay in the program was 163 days (210 for in-person, 134 for online) with interquartile range of 238 (231 for in-person, 161 for online). The reasons for leaving the program are not collected; only information such as participant demographics, type of program delivery (in-person or online), and date of the first session attended can be assessed. To determine whether retention is related to the time of year a participant enters the program, a seasonal model was applied, where the response variable was the number of days a participant stayed in the program. Separate models were run for all participants, and by sex and delivery mode, to look at the impact of start date on retention. Overall, participants who started the program on day 267 (September) were predicted to stay in the program longest: 178 days (95% CI: 176, 179). The range of predicted days was 137-178. Longest predicted number of days in the program for men and women was 161 (158, 164) and 182 (180,184), respectively, and was also associated with September start dates. In-person participants who started on day 270 (September) were predicted to have the longest stay, 218 (216, 220) with range of 192-218. Estimates for online participants showed a maximum of 142 days (140, 144), which was associated with start dates in June (day 163) and had a range of 128-142. All models predicted that the shortest stay in the program was associated with starting in November. Retention is strongly associated with enrollment timing; this information may be helpful as organizations plan future classes.


E. Ely: None. M. Bell: None.

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