Figure 3.

ORs for adherence among participants who took study metformin during DPPOS and reported adherence problems at one or more visits (n=478*). Panel A: includes assessing number of barriers metformin adherence (1 vs >1) and number of strategies to promote metformin adherence (1, >1 vs 0). Panel B: includes assessing types of barriers to adherence and types of strategies to improve adherence. ORs and CIs were calculated from a GEE model with metformin adherence as the outcome and variables listed in the figure as covariates in a multivariate model. Age, marital status, educational level, employment status, and income level were all measured at DPP baseline. The follow-up SF-36 and concomitant medications variables are averaged over follow-up visits. In these models, barriers and strategies (both number and category) were included as time-varying covariates (ie, the reported values at each participant-visit). Depression scores, anxiety scores, and number of concomitant medications were included in the models as logged values, so estimates of OR for these covariates are expressed per 1-unit log increase. *Only participants who reported problems taking their study metformin at one or more visits were included in this analysis, as only those participants had interview data collected on barriers and strategies to study metformin use. DPP, Diabetes Prevention Program; DPPOS, DPP Outcomes Study; GEE, generalized estimating equation; SF-36, Short Form-36.