https://orcid.org/0000-0002-9492-1040
Abstract
Purpose
Treatment interruption and incorrect dosage for measuring drug non-adherence have seldom been studied in multidrug-resistant tuberculosis (MDR-TB) treatment. This study aimed to 1) estimate the overall and drug-specific incidence of short (≤14 days) and serious (>14 days) treatment interruption among MDR-TB patients, 2) identify main reasons and predictors for serious interruption, and 3) document the level of agreement of classification for incorrect drug dosage between self-report and pill count.
Patients and methods
A cross-sectional study combining hospital-based interviews and home-based pill count was conducted from January to June 2018. Treatment interruption was determined from patient’s medical records and interviews using a structured questionnaire among 202 patients treated at one designated hospital for MDR-TB treatment. Concordance of pills counted with self-reports for each drug use within one month was assessed for a subgroup of patients at their homes using kappa statistics.
Results
Of 202 patients, the incidence of short and serious treatment interruption was 37.6% and 28.7%, respectively. Adverse drug reactions (ADRs) and financial hardship were the top two reasons for serious interruption. Amikacin and cycloserine had the highest rate of specific drug interruption (18.3% and 10.2%, respectively). ADRs (ORadj: 2.82, 95% CI: 1.41–5.61), monthly out-of-pocket expenses exceeding 250 US dollars (ORadj: 2.27, 95% CI: 1.14–4.50), and baseline co-morbidities (ORadj: 2.53, 95% CI: 1.19–5.38) were significantly associated with serious treatment interruption. Of 111 patients assessed for pill count at home, 5.4% had perfect drug adherence, 54.1% had drug under-use, 6.3% had drug over-use, and 34.2% had both problems. The respective number from self-reports was 7.2%, 56.8%, 5.4% and 30.6%. The two methods gave an acceptable level of agreement for most of the drugs (kappa: 0.52–0.95).
Conclusion
Close monitoring of ADRs, revision of drug regimens, and financial support for MDR-TB in this study population are needed. Self-report on drug under-use and over-use should be monitored monthly in clinical settings.
Acknowledgments
This study is a part of the first author’s thesis in partial fulfillment of the requirements for a PhD at Prince of Songkla University, Thailand, and the training program for TB/MDR-TB research supported by the Fogarty International Center, Grant number D43TW009522. The study was funded by the China Medical Board, the National Natural Science Foundation of China (grant number 81860591), and the Guizhou Science and Technology project (grant number [2016]1508). The authors thank all patients for participating in this study and all research team members for their support during data collection.
Disclosure
The authors report no conflicts of interest in this work.