Planned comparisons
CM
REGRESSION
Hypothesis 1: We predict that a higher percentage of those in the CM condition will be adherent after 4 weeks of intervention than those in BSM: Comparison of proportions and logistic regression with adherent yes/no as dependent variable includes baseline demographics, etc., as explanatory variables. We are adequately powered to test this hypothesis as well as the question whether there are differences in adherence after the 6-month maintenance period depending on initial treatment assignment.Hypothesis 2: Based upon evidence of diminished effects of CM over time, we predict that those in CM (vs. BSM) will show decreases in adherence during the 8-month follow-up: Approach is as for Hypothesis 1 above but based on all entering the maintenance phase after being adherent for 4 weeks. We have adequate power only if the relative difference between these two groups is large (80% power to detect, e.g., 10% vs. 32% subsequent non-adherence, assuming stage-1 adherence proportions of Hypothesis 3: We predict that the combined CM + BSM will have the highest treatment effect among those who are initially non-adherent, given the greater intensity of intervention. Comparison of the relevant final adherence proportions in the participants re-randomized, using Tukey’s Honest Significant Difference (HSD) procedure to adjust for the multiplicity in the pairwise comparisons. We expect to have a minimum of 23 individuals in the smallest of these re-randomized groups, but do not expect to be powered to authoritatively conclude about this hypothesis. We will report our findings including 95% confidence intervals to facilitate the planning of future clinical trials and subsequent meta-analytical approaches.