Patient Preference and Adherence (Nov 2016)
Adverse events and patients’ perceived health-related quality of life at the end of multidrug-resistant tuberculosis treatment in Namibia
Abstract
Evans L Sagwa,1 Nunurai Ruswa,2 Farai Mavhunga,2 Timothy Rennie,3 Hubert GM Leufkens,1,4 Aukje K Mantel-Teeuwisse1 1Division of Pharmacoepidemiology and Clinical Pharmacology, Utrecht Institute for Pharmaceutical Sciences, Utrecht University, Utrecht, the Netherlands; 2National Tuberculosis and Leprosy Program, Ministry of Health and Social Services, Windhoek, Namibia; 3Department of Pharmacy Practice and Policy, University of Namibia School of Pharmacy, Windhoek, Namibia; 4Medicines Evaluation Board, Utrecht, the Netherlands Purpose: The 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 methods: A 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-8™ (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. Results: Overall, 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. Conclusion: Patients 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. Keywords: drug safety, patient-reported health outcomes, SF-8™ questionnaire, second-line tuberculosis drugs, Namibia
