Power was calculated a priori for the primary outcome of the 3-month dose of methadone. We anticipated that dose escalations after initial titration would be recommended for approximately 70% of participants in the TAU cohort in that time frame, basing this approximation on discussions with clinic staff on the proportion of patients who receive dose increases at this opioid treatment program. Thus, 60 participants per group would yield a power of 0.
We adopted a second, more stringent analysis to account for the potential barrier to analyzing group differences on the 90th-day methadone dose: a missed dose on the 90th day or a temporary need for a lower dose on that day due to 2 or more consecutive missed days just before the 90th day would preclude a stabilization dose of methadone, which would have potentially hidden any group differences.
Among 320 new patients screened for methadone treatment, 131 individuals met eligibility criteria, provided informed consented, were randomized to receive C-OLP or TAU , and completed all of day 1 and baseline procedures (