BackgroundAmikacin and kanamycin are mainly used for treating multidrug-resistant tuberculosis (MDR-TB), especially in developing countries where the burden of MDR-TB is highest. Their protracted use in MDR-TB treatment is known to cause dose-dependent irreversible hearing loss, requiring hearing aids, cochlear implants or rehabilitation. Therapeutic drug monitoring and regular audiological assessments may help to prevent or detect the onset of hearing loss, but these services are not always available or affordable in many developing countries. We aimed to compare the cumulative incidence of hearing loss among patients treated for MDR-TB with amikacin or kanamycin-based regimens, and to identify the most-at-risk patients, based on the real-life clinical practice experiences in Namibia.MethodsWe conducted a retrospective cohort study of patients treated with amikacin or kanamycin-based regimens in four public sector MDR-TB treatment sites in Namibia between June 2004 and March 2014. Patients were audiologically assessed as part of clinical care. The study outcome was the occurrence of any hearing loss. Data were manually extracted from patients’ treatment records. We compared proportions using the Chi-square test; applied stratified analysis and logistic regression to study the risk of hearing loss and to identify the most-at-risk patients through effect-modification analysis. A P-value < 0.05 was statistically significant.ResultsAll 353 patients had normal baseline hearing, 46 % were HIV co-infected. Cumulative incidence of any hearing loss was 58 %, which was mostly bilateral (83 %), and mild (32 %), moderate (23 %), moderate-severe (16 %), severe (10 %), or profound (15 %). Patients using amikacin had a greater risk of developing the more severe forms of hearing loss than those using kanamycin (adjusted odds ratio (OR) = 4.0, 95 % CI: 1.5–10.8). Patients co-infected with HIV (OR = 3.4, 95 % CI: 1.1–10.6), males (OR = 4.5, 95 %1.5–13.4) and those with lower baseline body weight (40–59 kg, OR = 2.8, 95 % CI: 1.1–6.8), were most-at-risk of developing hearing loss.ConclusionAmikacin use in the long-term MDR-TB treatment led to a higher risk of occurrence of the more severe forms of hearing loss compared to kanamycin use. Males, patients with low baseline body weight and those co-infected with HIV were most-at-risk. MDR-TB treatment programmes should consider replacing amikacin with kanamycin and strengthen the routine renal, serum therapeutic drug levels and audiometric monitoring in the most-at-risk patients treated with aminoglycosides.Electronic supplementary materialThe online version of this article (doi:10.1186/s40360-015-0036-7) contains supplementary material, which is available to authorized users.

Generally, the absolute risks and risk factors for adverse events were similar between HIV-infected and HIV-uninfected patients treated for DR-TB in our Namibian cohort of 57 patients. Although our findings of comparable adverse event risks between DR-TB and DR-TB/HIV co-infected patients are encouraging, they are inconclusive because of the low statistical power of our study. We recommend a prospective study with a larger sample size that would increase the power and therefore the confidence in the results.

Setting: Directly Observed Treatment Short-course is a key pillar of the global strategy to end tuberculosis. Objective: The effectiveness of community-based compared to facility-based DOTS on tuberculosis treatment success rates in Namibia was assessed. Methods: Annual tuberculosis treatment success, cure, completion and case notification rates were compared between 1996 and 2015 by interrupted time series analysis. The intervention was the upgrading by the Namibian government of the tuberculosis treatment strategy from facility-based to community-based DOTS in 2005.Results: The mean annual treatment success rate during the pre-intervention period was 58.9% (range: 46-66%) and significantly increased to 81.3% (range: 69-87%) during the post-intervention period. Before the intervention there was a non-significant increase (0.3%/year) in the annual treatment success rate. After the intervention, the annual treatment success rate increased abruptly by 12.9% (p <0.001) and continued to increase by 1.1%/year thereafter. The treatment success rate seemed to have stagnated at approximately 85% at the end of the observation period. Conclusion:Expanding facility-based DOTS to community-based DOTS significantly increased the annual treatment success rates. However, the treatment success rate at the end of the observation period had stagnated below the targeted 95% success rate.

ObjectivesTo determine the incidence of symptomatic moderate-to-severe adverse events during treatment of drug-resistant tuberculosis, and to compare their risk and outcomes by patients’ human immunodeficiency virus (HIV) co-infection status.MethodsWe conducted a retrospective cohort analysis of patients treated for drug-resistant tuberculosis between January 2008 and February 2010. Routinely, clinicians monitored and managed patients’ response to treatment until its completion. Any symptomatic adverse event observed by the clinician or reported by the patient was recorded in the standard patient treatment booklet of the National Tuberculosis and Leprosy Programme. There were 18 symptomatic adverse events routinely monitored. Depending on the nature of the medical intervention needed, each was graded as mild, moderate or severe. Data were extracted from the patient treatment booklet using a structured form, then descriptive, bivariate and Cox proportional hazard analysis performed, stratified by patients’ HIV infection status. Statistical associations were done at the 5% level of significance and reported with 95% confidence intervals.ResultsFifty seven (57) patients with drug-resistant tuberculosis were identified, 31 (53%) of whom were HIV co-infected. The cumulative incidence of moderate-to-severe adverse events was 46 events in 100 patients. HIV co-infected patients experienced more moderate-to-severe adverse events compared with the HIV uninfected patients (median 3 versus 1 events, p = 0.01). They had a four-fold increase in the cumulative hazard of moderate-to-severe adverse events compared with the HIV uninfected patients (HR = 4.0, 95% CI 1.5 – 10.5). Moderate-to-severe adverse events were the main determinant of a clinician’s decision to reduce the dose or to stop the suspected offending medicine (RR = 3.8, 95% 1.2-11.8).ConclusionsModerate-to-severe adverse events are common during drug-resistant tuberculosis therapy. They are more likely to occur and to persist in HIV co-infected patients than in HIV uninfected patients. Clinicians should employ various strategies for preventing drug-induced patient discomfort and harm, such as reducing the dose or stopping the suspected offending medicine. Managers of tuberculosis control programmes should strengthen pharmacovigilance systems. We recommend a more powered study for conclusive risk-factor analysis.Electronic supplementary materialThe online version of this article (doi:10.1186/2052-3211-7-14) contains supplementary material, which is available to authorized users.

PurposeThe health-related quality of life (HRQoL) of patients completing multidrug-resistant tuberculosis (MDR-TB) treatment in Namibia and whether the occurrence of adverse events influenced patients’ rating of their HRQoL was evaluated.Patients and methodsA cross-sectional analytic survey of patients completing or who recently completed MDR-TB treatment was conducted. The patients rated their HRQoL using the simplified Short Form-™ (SF-8) questionnaire consisting of eight Likert-type questions. Three supplemental questions on the adverse events that the patients may have experienced during their MDR-TB treatment were also included. Scoring of HRQoL ratings was norm-based (mean =50, standard deviation =10) ranging from 20 (worst health) to 80 (best health), rather than the conventional 0–100 scores. We evaluated the internal consistency of the scale items using the Cronbach’s alpha, performed descriptive analyses, and analyzed the association between the patients’ HRQoL scores and adverse events.ResultsOverall, 36 patients (20 males, 56%) aged 17–54 years (median =40 years) responded to the questionnaire. The median (range) HRQoL score for the physical component summary was 58.6 (35.3–60.5), while the median score for the mental component summary was 59.3 (26.6–61.9), indicating not-so-high self-rating of health. There was good internal consistency of the scale scores, with a Cronbach’s alpha value of >0.80. In all, 32 (89%) of the 36 patients experienced at least one adverse drug event of any severity during their treatment (median events =3, range 1–6), of which none was life-threatening. The occurrence of adverse events was not related to HRQoL scores. For patients reporting zero to two events, the median (range) HRQoL score was 56.8 (44.4–56.8), while for those reporting three or more events, the median score was 55.2 (38.6–56.8); P=0.34 for difference between these scores.ConclusionPatients completing treatment for MDR-TB in Namibia tended to score moderately low on their HRQoL, using the generic SF-8 questionnaire. The occurrence of adverse events did not lead to lower HRQoL scores upon treatment completion.