The sub-sample of HIV positive patients on dual therapy for TB and HIV infection, in this study, shared a similar economic and alcohol misuse profile to the total sample of TB infected patients. In addition, nearly 40% of patients on dual therapy reported having a partner who is HIV positive. Finally, the self-report of non-adherence to dual therapy is high in this sub-sample (42.4%) but comparable to the figures reported in the literature . Non-adherence to both ART and anti-TB drugs are of concern in this sub-group. However, given the fact that this sub-group has a dual infection requires that they take two sets of drugs, which could prove to be quite burdensome. The use of a multiple drug regimen may also lead to drug reactions causing unmanageable side-effects ultimately leading to treatment default [28–30]. The complexity of the drug treatment regimen and the impact on the daily lives of these patients are also factors that are associated with poor adherence in these patients [29, 30]. Patients on strict drug treatment programmes also have daily competing “life demands” associated with work and family.
The four common predictive factors independently associated with non-adherence to anti-TB drugs and to dual therapy (i.e. ART and anti-TB drugs) were poverty, having co-morbid disease conditions, being at risk for alcohol misuse and having a HIV positive partner. This finding is supported by existing literature on the relationship between the social determinants of health and health outcome and/or the quality of life of individuals with one or more disease condition [31, 32]. In this study non-adherent behavior for both anti-TB drugs and ART was associated with a lack of economic resources (poverty) and negative personal circumstances (co-morbid conditions and a HIV positive partner). Clearly the lack of social, personal and economic resources is a barrier to adherence. Unfortunately, the lack of resources, in particular poverty, has historically been associated with TB onset . It stands to reason, therefore, that being poor is a barrier to health promoting behavior, such as adhering to a treatment programme, because individuals faced with economic restraints do not have an enabling environment that facilitates behavior that will lead to better health outcomes. Being poor, having negative personal circumstances and engaging in risky behavior such as alcohol misuse is likely to lead to poor health outcomes as a consequence of treatment default [13, 34]. It is plausible that patient mis-use of alcohol, in particular, may have led to poor and impaired judgement [35, 36] when making health decisions, such as not adhering to their anti-TB medication.
Of particular concern in this study is the fact that HIV negative participants’ who were non-adherent to anti-TB drugs and in a relationship with a HIV positive partner, placed not only themselves but their partners at risk for poor health outcomes. Inconsistent adherence to anti-TB drugs may not only lead to MDR and XDR-TB but may increase the risk of transmission of TB to others living and working in close proximity. The HIV positive patients, in this study, who were not adhering to dual therapy, placed themselves at risk for drug resistance which could in turn reduce their life-span. ART, taken in accordance with treatment guidelines is known to prolong an HIV infected person’s life and the availability of ART has led health professionals to re-conceptualize HIV and AIDS as chronic medical conditions.
One additional factor, namely tobacco use, was independently associated with non-adherence to TB treatment drugs. Individuals who smoke tobacco may be conceived of as having a personality with an “increased risk profile” which makes them prone to engaging in undesirable behaviours regardless of the consequences [35, 36]. It is not surprising, therefore, that participant’s adherence to anti-TB drugs in this study, was mediated by tobacco smoking.
The common predictive factor independently associated with adherence to anti-TB drugs and to dual therapy (i.e. ART and ant-TB drugs) was: perceiving health status to be poor. This finding may seem counter-intuitive at first glance. It is reasonable, however, that the participants who perceived that their health status was poor on the basis that they had a “double-disease” burden of being infected with TB and HIV were more motivated to take the medication which they know to be an effective form of treatment. Knowledge of medical treatment efficacy for a specific disease condition is known to influence the adherence behavior of the recipients of care .
Additional predictive factors for adherence to TB treatment were: perceiving health status to be good and being HIV negative. This finding is supported by the literature that reports on factors found to be influencing adherence to medical treatment regimens for communicable and non-communicable diseases. Individuals with a transient medical condition, that can be cured, equipped with the knowledge that heeding to health care practitioner’s suggested treatment regimens for cure are more likely to adhere . Of course there are numerous other factors that may influence adherence to medication for a curable disease, such as TB. These factors include knowing someone who was cured, the need to maintain a good health status, and having a high level of health literacy (such as knowledge of disease transmission as in the case of TB) [7, 32].
The results indicate that there is a trend between perceived health status and adherence in the anti-TB treatment group and the dual treatment group. In the anti-TB treatment group health status perceived to be good is associated with adherence to treatment but this is not the case in the smaller group receiving dual treatment.
Finally, the additional predictive factor for adherence to dual therapy (i.e. anti-TB treatment and ART) was having a sex partner on ART. Having a sex partner on ART is in some way a protective factor for an individual who is also on ART because of the sero-concordant nature of the relationship. Both partners in this relationship are able to support each other in an open manner without fear of being stigmatized for being HIV positive [38, 39]. Non-disclosure of certain medical conditions, such as having HIV or AIDS, is known to fuel the epidemic . Consequently, one may assume that in households where there is non-disclosure of HIV status, the adherence to ART will be non-existent, poor or inconsistent for fear of one’s HIV positive status being revealed . In essence social support has a positive association with medical treatment adherence .