4.1.1 Primary research question
The primary research question of my PhD is: “How cost-effective is home-based HIV self-testing in Blantyre, Malawi?” In order to answer my research question, I needed to decide on the appropriate methods. As the research was being undertaken in the context of a larger cluster-randomised trial, it provided an opportunity to collect primary data from participants of the trial who have been randomised to receive or not receive the exposure of interest (HIV self-testing). This was also necessary because of the lack of relevant data to answer this question.
A recent publication by Cambiano and colleagues highlights 18 issues with regards to lack of data they encountered when trying to evaluate the cost-effectiveness of HIVST (Cambiano et al., 2014, Cambiano et al., 2015). As highlighted in the previous and preceding chapters of this thesis, there are probably even more data needs than that. Of note, the authors only mention two issues with regards to costs and health- related quality of life (highlighted below) (Cambiano et al., 2014).
“What is the cost of implementing HIVST in resource-limited settings?” “What is the quality of life following a positive or a negative HIVST as
These two issues are likely to play an important role in the investigation of the cost- effectiveness of HIVST. However, other issues regarding costs and quality of life need to be considered also. An economic evaluation is a comparative analysis of the costs and consequences of an intervention, and consequently will also require the investigation of the costs and quality of life consequences of HIVST and current approaches to providing HIV testing and counselling. For example, does it cost the same to manage someone on ART who self-tested as someone who accessed HIV testing at the health facility? Do those who self-tested have the same health-related quality of life as facility testers after they access HIV treatment? In addition, HIV testing is the entry point into accessing HIV treatment, and when someone starts ART has an impact on their subsequent risk of developing HIV associated diseases. If offering HIVST results in more timely initiation of ART amongst those who test positive, many of these HIV associated diseases could be averted.
4.1.2 Rationale of overall study design
In answering my main research question I used decision-analytic modeling to undertake a cost-utility analysis (CUA). The on-going study (HitTB study) is a cluster- randomised trial. Undertaking an economic evaluation alongside a randomised clinical trial potentially provides the least biased estimates for economic and health outcomes data.
HIV testing strategies reach different populations and at differing stages in their disease progression. As this impacts on subsequent health outcomes and cost of providing care, there is a need to incorporate the long-term costs and health outcomes subsequent to entering HIV care. Whilst it may have been possible to follow-up Hit-TB trial participants, the large sample sizes and long follow-up suggested a decision-analytical modelling approach would be more efficient, and enabled the incorporation of other relevant evidence from secondary sources (Petrou and Gray, 2011b, Buxton et al., 1997).
In addition, whilst there is a lack of primary economic data with regards to HIV, there is a large amount of research undertaken to investigate outcomes amongst HIV positive individuals who have and have not started anti-retroviral therapy. Decision- analytic models allows us to synthesize this data, analogous to performing a meta- analysis, so that estimates of cost-effectiveness are potentially based on all the available evidence rather than from evidence from a single randomised trial (Drummond et al., 2005b, Briggs et al., 2008, Briggs et al., 2012b).
4.1.3 Aims and objectives
The broad aim is to investigate the costs and health benefits of providing residents in Blantyre, Malawi access to HIV self-testing (HIVST) in addition to facility-based HIV testing and counselling (HTC) services, thereby allowing estimation of its value for
money within an economic evaluation framework. The specific primary and secondary objectives of the PhD are listed below.
Primary objective:
To undertake a decision-analytic modelling based cost-utility analysis to estimate the incremental cost per quality-adjusted life year (QALY) gained from the provision of HIV self-testing in conjunction with traditional facility- based HIV testing and counselling services in Blantyre, Malawi.
-> Investigated in Chapter 8 of PhD
Secondary objectives:
To compare and contrast the costs to individuals and to healthcare providers, and health-related quality of life outcomes, amongst individuals who access facility-based or HIV self-testing services in Blantyre, Malawi.
-> Investigated in Chapter 5 of PhD
To compare and contrast the costs to individuals and to healthcare providers, and health-related quality of life outcomes, amongst HIV positive individuals who access HIV care and treatment services subsequent to testing at facility- based or through HIV self-testing services in Blantyre, Malawi.
To estimate the costs, to individuals and to healthcare providers, and health- related quality of life of adults who are admitted to the medical wards in Queen Elizabeth Central Hospital, Blantyre, Malawi, for the management of medical illnesses.
->Investigated in Chapter 7 of PhD
To investigate the relative impact of HIV infection on costs and health-related quality of life of adults who are admitted to the medical wards in Queen Elizabeth Central Hospital, Blantyre, Malawi, for the management of medical illnesses.