Although there is effective treatment available for Tuberculosis (TB), prior to Covid-19, it had been responsible for the greatest number of deaths worldwide by a single infectious agent. More research regarding predicting and improving people’s adherence to treatment is essential if the World Health Organisation’s goal to eliminate TB by 2035 is to be met.
This is the view of clinical psychologist Dr Leigh Rynhoud, who recently obtained her doctorate in Psychology at Stellenbosch University. She evaluated the effectiveness of the Health Belief Model (HBM) and demographic factors, beliefs about medicines, substance use and symptoms of depression to predict medication adherence in those hospitalised with TB.
The HBM is a widely used theory to understand and predict health behaviours. Based on the HBM, people are more likely to adhere to treatment for TB when they perceived they were susceptible to development of resistance, believed that TB is a severe illness, perceived greater benefits of treatment with fewer barriers, and perceived they were capable of adherence, in an environment where adherence was encouraged by cues to action.
As part of her doctoral study Rynhoud developed the Tuberculosis Adherence Scale to measure adherence to TB treatment. She also designed the Tuberculosis Health Belief Scale to measure the HBM constructs pertaining to TB and adherence. Rynhoud obtained information regarding demographic and socio-economic factors, substance use, beliefs about medicine, health beliefs, depression, and adherence from 175 participants who were recently hospitalised with TB. Both these hospitals were specialised TB hospitals located in the Western Cape.
Rynhoud says her study showed that participants who were hospitalised for TB treatment had lower socio-economic status than the general population of the Western Cape, had high levels of substance use and just under 50% had symptoms of depression that were above the normal to mild category of severity.
“The results showed that 58 participants (33,1%) had low adherence, 60 participants (34,3%) had medium adherence, and 57 participants (32,5%) had high adherence.
“Most participants believed in their ability to adhere to treatment and in its benefits and necessity of treatment. They were aware that TB is potentially dangerous and that non-adherence to treatment could be harmful.
“Some participants were concerned about the medication and the potential harmful effects, while the perceived threat of developing drug-resistant TB was also high.”
Rynhoud adds that health-care workers should also be mindful of people’s beliefs about medication – especially regarding long-term effects and addiction. She points out younger participants and those who consumed less alcohol, had fewer symptoms of depression, less concerns about the harmful effects of TB treatment and were meaningfully occupied, were more likely to adhere to treatment.
Rynhoud says targeted interventions are needed to identify and address the challenges people with TB face to ensure optimal adherence to treatment and improved outcomes.
“The Tuberculosis Health Belief scale can provide valuable information regarding personal beliefs and circumstances that could hinder adherence to treatment,” he said. “Strategies that address people’s perceptions of TB as well as minimise barriers and maximise benefits of treatment should improve adherence to treatment.”
Rynhoud says a surprising finding of her study was that fear related to the threat of TB was negatively associated with improved adherence. She suggests health-care providers should refrain from using strategies aimed primarily at heightening fear of the consequences of poor adherence. They must also emphasise the benefits of treatment.
“Timely identification of poor adherence is essential to address challenges before potential drug resistance is amplified, disease progresses, and period of infectivity increased. This is especially true with the recent introduction of new medications to treat drug-resistant TB.”
Rynhoud says the Tuberculosis Adherence Scale should be used to measure adherence at regular intervals.
He says since more symptoms of depression and higher substance use were significantly associated with non-adherence to treatment, this situation obviously needs to be addressed.
