Association between Health-Related Quality of Life and Medication Adherence in Pulmonary Tuberculosis in South Africa.

Tanja Kastien-Hilka,Edina Sinanovic,Bernd Rosenkranz,Bryan M Bennett,Matthias Schwenkglenks

doi:10.3389/fphar.2017.00919

Abstract

Background: Health-related quality of life (HRQOL) and adherence to treatment are two often inter-related concepts that have implications for patient management and care. Tuberculosis (TB) and its treatment present a major public health concern in South Africa. The study aimed to evaluate the association between HRQOL and adherence in TB patients in South Africa.Methods: Four self-reported HRQOL and one self-reported adherence measures were used in an observational longitudinal multicentre study during 6-month standard TB treatment. These included the generic Short-Form 12 items (SF-12) and European Quality of Life 5 dimensions 5 levels (EQ-5D-5L), the disease-specific St. George's Respiratory Questionnaire (SGRQ) and the condition-specific Hospital Anxiety and Depression Scale (HADS) for HRQOL. Adherence was measured by the Morisky Medication Adherence Scale 8 items (MMAS-8). The relationship between both concepts was examined in 131 patients using Spearman's rho correlations, and linear regression models.Results: HRQOL improved over 6-month TB treatment, whereas adherence mean scores stayed constant with participants attaining a medium average level. Around 76% of patients reported to be high adherers and 24% were reporting a medium or low adherence. Associations between HRQOL and adherence were mainly weak. High adherence at treatment start was positively related to improvements in anxiety and depression after 6-month treatment. The overall improvement in pain and discomfort, and psychosocial health aspects over treatment time was positively, but weakly associated with adherence at 6 months of treatment.Conclusion: A positive relationship exists between adherence and HRQOL in TB in a South African setting, but this relationship was very weak, most likely because HRQOL is affected by a number of different factors and not limited to effects of adherence. Therefore, management of TB patients should, besides adequate drug treatment, address the specific mental and psychosocial needs.

Highlights

Both adherence and health-related quality of life (HRQOL) are important indicators for the effectiveness and treatment success of therapeutic interventions (Côté et al, 2003)
Significant, but weak correlations were observed with the overall improvement of the Hospital Anxiety and Depression Scale (HADS) Anxiety (r = 0.226 P = 0.026), EQ-5D Pain/Discomfort (r = 0.232 P = 0.026) and St. George’s Respiratory Questionnaire (SGRQ) Impacts (r = 0.291 P = 0.005) domains, and with the SGRQ total score (r = 0.226 P = 0.014). All these results indicated that an improvement in HRQOL between baseline and follow-up visit 4 was positively associated with higher adherence
Despite treatment complexity being a predictive factor for low adherence in other conditions, the results of this study demonstrate that adherence to TB treatment within South Africa was high, and remained high throughout both the intensive and continuous treatment phases

Summary

Introduction

Both adherence and health-related quality of life (HRQOL) are important indicators for the effectiveness and treatment success of therapeutic interventions (Côté et al, 2003). Determinants of adherence behavior are well-established in the literature (Kardas et al, 2013). Psychosocial factors, such as poor levels of education, have been shown to influence whether patients are adherent with their medication. Treatment-related factors, such as complexity (Pantuzza et al, 2017) and number of drugs (Sabaté, 2003), have a negative impact on adherence in many different chronic conditions. Health-related quality of life (HRQOL) and adherence to treatment are two often inter-related concepts that have implications for patient management and care.

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