Statistical methods
SECONDARY
The study used a cluster randomized controlled trial design. Both simple means, as well as generalized estimating equation models, with compound symmetric working correlation structure, were used to estimate the difference in accomplishment of our composite outcome between groups randomized to the PP intervention arm versus the wait-list control arm. Participants who were missing 12-months follow-up information used for estimation of the composite outcome measure were excluded from our primary analysis. For primary study objectives, we analyzed groups (with non-missing baseline/follow-up data) as randomized using a modified ITT principle; whereas for secondary objectives related to COVID-19 pandemic impacts on trial implementation we also present per protocol estimates of the PP intervention effect (the per-protocol sub-analyses acknowledge that some sites had trouble implementing the PP intervention during the pandemic). To evaluate demographic and clinical characteristics associated with differences in composite outcome score, estimates of the adjusted impact of intervention/PP after controlling or accounting for other variables in the linear GEE model (with compound symmetric working correlation structure) were used.