Incidence, types and predictors of adverse events and their impact on treatment outcomes in multidrug/rifampicin resistant tuberculosis patients receiving all oral treatment regimens.

Background: Patients suffering from multidrug/rifampicin resistant tuberculosis (MDR/RR-TB) are treated for prolonged periods with a complex regimen comprised of relatively less effective and more toxic anti-TB drugs, consequently resulting in high incidence of adverse events (AEs).

Study aim: The current study evaluates the incidence, types, management and predictors of AEs, and their impact on treatment outcomes in MDR/RR-TB patients receiving all oral treatment regimens.

Study design: A total of 242 eligible MDR/RR-TB patients treated at two different study sites from June 2019 to December 2021 were included in this study.

Measures and outcomes: Patients' sociodemographic, microbiological, clinical characteristics, reported AEs and treatment outcomes were retrospectively abstracted from their medical records. Chi-square, and Fisher exact tests (wherever applicable) were used to find the association between the variable and the occurrence of AEs.

Results: Majority of the patients were suffered from MDR-TB (71.9%) and were treated with longer treatment regimen (77.7%). Overall 206/242 patients (85%) experienced at least one AE during their treatment. Gastrointestinal disturbance was the most common AE (49.6%), followed by arthralgia (49.2%), psychiatric disturbances (39.3%), dermatological reactions (27.7%), body/headache (24.8%) and hyperuricemia (19%). Due to AEs, treatment modification was noted in 55 (22.72%) patients. Level of modification in the treatment regimen was higher in optic neuritis (100%) followed by neuropathies (80%) and myelosuppression (59%). Similarly, hepatotoxicity was the most serious AE in which the whole treatment regimen was terminated in 27% of patients. Furthermore, the results revealed that only patients' education status had statistically significant association with the incidence of AEs (p = 0.02). The treatment success rate was 80.6% whereas the ratio of died and LTFU patients were 15.3% and 4.1% respectively. Although patients who experienced AEs were more likely to develop successful treatment outcomes (82%) than their counterparts (72.2%), though this difference was not statistically significant.

Conclusion: Although AEs were highly present in the current cohort, but they were successfully managed mostly by nonpharmacological interventions or symptomatic treatment. Besides, the incidence of AEs did not have a negative impact on treatment outcomes. High-risk patients for AEs must receive special attention and enhanced clinical management.