Objective: To determine the level of and reasons associated with adherence to tuberculosis preventive therapy among asymptomatic HIV-infected individuals in northern Thailand.
Design: A prospective cohort study with a 9-month follow-up.
Methods: A total of 412 HIV-infected persons were enrolled in a tuberculosis preventive therapy programme in a hospital. A 9-month isoniazid regimen was prescribed. Adherence was determined by pill count. Participants who missed a scheduled appointment for more than a month were interviewed. Five focus group discussion sessions were held among those who successfully completed the therapy.
Results: Of the 412 participants, 69.4% (286) completed the 9-month regimen. The adherence rate, defined as the proportion of those who took more than 80% of pills, was 67.5% (n = 278). Sex, source of participants and history of physical symptoms were associated with adherence. A significant portion of defaults took place at the beginning of the therapy. Out-migration, denial of HIV status, and perceived side effects of isoniazid were frequently cited as reasons for non-adherence. For those adhering participants, the acceptance of personal HIV status, concern about children and family, and a good health provider relationship were important reasons motivating adherence. Several reminder systems were developed by the participants.
Conclusions: Although a isoniazid preventive therapy programme was shown to be feasible, further adjustments on the selection of participants, enrollment process, and follow-up system based on these findings are necessary to increase the adherence.
PIP: A prospective study of 412 men and women infected with human immunodeficiency virus (HIV) who were enrolled in a hospital-based tuberculosis prevention program in Chiang Rai, Thailand, identified factors that contribute to non-adherence. Program participants were provided a 9-month supply of isoniazid, which has been shown to be effective in reducing the risk of developing clinical tuberculosis among asymptomatic HIV-infected individuals. Of the 412 individuals enrolled in the program, 286 (69.4%) completed the treatment regimen, 109 (26.5%) defaulted by failing to take the medicine for more than 60 consecutive days, and 17 (4.1%) developed acquired immunodeficiency syndrome (AIDS) or died. Among defaulters, 20 restarted the regimen and eventually complied with treatment, raising the completion rate to 74.3%. Married people, women, outpatients, surviving spouses, the self-employed, and those with no history of physical symptoms were more likely to be adherent. The primary reasons for default included outmigration for job search, denial of HIV status, perceived drug side effects, and confusion about the duration of treatment. Although this study suggests that good adherence to a tuberculosis prevention regime is possible among HIV patients, it highlights factors that should be considered (especially migration potential) in the selection of participants.