A. Trajman, R. Long, D. Zylberberg, M. J. Dion, B. Al-Otaibi, D. Menzies
SETTING: Randomised controlled trial of latent tuberculosis infection (LTBI) treatment in 10 clinics in Canada, Saudi Arabia and Brazil.
OBJECTIVE: To identify early predictors of LTBI treatment adherence, including pre-treatment characteristics.
DESIGN: Patients randomised to 4 months of rifampicin (RMP; n = 420) or 9 months of isoniazid (n = 427) were monitored for adherence using an electronic device. Outcomes were 1) treatment completion, defi ned as intake of ⩾80% of the prescribed doses, and further categorised as completed within the allotted time or not; and 2) treatment regularity, measured by the time interval between doses. Relative risk (RR) and adjusted odds ratios (aOR) of patients’ pre-treatment characteristics and adherence at fi rst follow-up visit were calculated.
RESULTS: Completion of treatment was higher with RMP (aOR 4.3, 95%CI 2.7–6.8). Early predictors (fi rst follow-up visit) of non-adherence were late fi rst visit attendance (RR for completion in time 0.9, 95%CI 0.8– 0.98), >20% of missed doses (RR 0.4, 95%CI 0.3–0.6) and greater variation of hours between doses (0.209 vs. 0.131, P < 0.001). Serious adverse events were not associated with irregularity of treatment.
CONCLUSION: The shorter RMP regimen was associated with better adherence. Patients with poor adherence could be identifi ed at the fi rst follow-up visit from their punctuality in follow-up, missed doses and variability of pill-taking.
KEY WORDS: adherence; compliance; isoniazid; rifampicin; tuberculosis