Background/aims
To examine how measuring adherence at 3 weeks by self-report and pill counts compares to measurements at 7 weeks in a pre-randomization run-in period.

Methods
Study within a trial of an international parallel group randomized controlled trial (RCT) that compares spironolactone to placebo. Adults receiving dialysis enter an 8-week active run-in period with spironolactone. Adherence was assessed by both self-report and pill counts in a subgroup of participants at both 3 weeks and 7 weeks.

Results
332 participants entered the run-in period of which 166 had complete data. By self-report, 146/166 (94.0%) and 153/166 (92.2%) had at least 80% adherence at 3 and 7 weeks respectively (kappa = 0.27 (95% C.I. 0.16 to 0.38). By pill counts, the mean (SD) adherence was 96.5% (16.1%) and 92.4% (18.2%) at 3 and 7 weeks respectively (r = 0.32) with a mean (SD) difference of 3.1% (17.8%) and a 95% limit of agreement from −31.7% to +37.9%. The proportion of adherent participants by self-report and pill counts at 3 weeks agreed in 87.4% of participants (McNemar’s p-value 0.58, kappa 0.11, p = 0.02) and at 7 weeks agreed in 92.2% (McNemar’s p-value 0.82, kappa 0.47, p < 0.001).

Conclusions
Three and seven-week run-in periods and both self-reported and pill count assessments performed similarly.

Collister D, Mbuagbaw L, Guyatt G, Devereaux PJ, Tennankore KK, Reis G, Sola L, Xavier D, Jha V, Gallagher M, Dans AL, Liu W, de Zoysa J, Félix C, Mark PB, Li Z, Tyrwhitt J, Wilkinson J, Sheridan P, Yuan F, Walsh M; ACHIEVE investigators

Contemporary Clinical Trials

Published 2021

Research Project: ACHIEVE