Cost-Effectiveness Analysis of HIV/AIDS Programme for Policy Decision in Nigeria: An Appraisal of Evidence Using the Drummond Checklist

1. Introduction

Acquired immune deficiency syndrome (AIDS) is a severe condition caused by the human immunodeficiency virus (HIV). About 80% of the world’s HIV population lives in sub-Saharan Africa (Ekwunife et al., 2018). The high burden of HIV/AIDS in sub-Saharan Africa remains a serious public health concern, and several interventions have been proposed and implemented at huge costs to reduce the burden of the disease. Within the past two decades, global organs such as Joint United Nations Programme on HIV/AIDS (UNAIDS) and the World Health Organisation (WHO), and other donor organisations have committed huge financial resources to mitigate the transmission and adverse effects of the disease, especially in low- and medium-income countries (UNAIDS, 2016 and 2023). Despite the enormous resources deployed on interventions to reduce related morbidity and mortality, very little progress has been made, with adolescents mostly affected on account of nonadherence to antiretroviral therapy (ART) and poor retention in care. Huge resources are being spent on (i) screening to identify status, (ii) ART drugs for treatment, (iii) medications for opportunistic diseases and care, (iv) counseling and education for voluntary screening, and behavioural change, (v) monitoring of treatment adherence, (vi) sensitization for community awareness to reduce exposure and transmission, support for programmes and lifestyle change, and reduce stigmatization of people living with HIV (PLHIV) (Philbin et al., 2014). Amidst emerging global and regional public health challenges of new and re-emerging infectious diseases like COVID-19, Ebola, Lassa fever, Mpox, etc., and the prolonged global economic downturn, the funding for HIV intervention has continued to dwindle (Gwandure and Mayekiso, 2013; Oladele et al., 2015; Serieux et al., 2015; WHO, 2024). The sustainability of new HIV interventions depends on the perceived net benefits amidst limited and scarce resources. Hence, the use of economic evaluation models such as cost-effectiveness analysis (CEA), cost-benefit analysis (CBA), cost-utility analysis (CUA), cost-consequence analysis (CCA), and cost-minimisation analysis (CMA), to determine the actual and potential net-benefits of programmes, as well as the opportunity cost of forgone alternatives as a result of any incremental cost, and to guide policymakers in selecting a more cost-effective programme has become an imperative (Alfirevic et al., 2016; Turner et al., 2021). This has become even more imperative with the funding challenge worsened by the United States review and restriction policy on foreign aid since 20 January 2025 which has been forecasted to adversely affect the HIV/AIDS programme under USAID and PEPFAR (KFF, 2025; NACA, 2025; Nigeria Health Watch, 2025).

2. Cost-effectiveness of HIV/AIDS intervention programmes

Several studies have examined the cost-effectiveness of some HIV/AIDS interventions in adolescents across the world with positive net benefits. However, the majority of such studies were in high-income countries (Mac-Pherson et al., 2015), with very few studies in low-income high-burden countries (Ekwunife et al., 2021). Economic evaluations of HIV/AIDS programmes to determine feasibility and effectiveness relative to costs have become imperative for the selection of more appropriate interventions for implementation. It is in light of the above construct that the economic evaluation work of Ekwunife et al. (2021) on the “Cost-effectiveness and feasibility of conditional economic incentives and motivational interviewing to improve HIV health outcomes of adolescents living with HIV in Anambra State, Nigeria” is being discussed using the Drummond 10-question checklist (Drummond et al., 2015).

2.1 The HIV/AIDS Intervention Cost-Effectiveness Study by Ekwunife et al. (2021)

The study was conducted as a cluster-randomised controlled trial (c-RCT) of the importance of an adolescent-centered intervention based on the published protocol of Ekwunife et al. (2018). The study sought to determine if there was any economically justifiable basis for such incentive-based intervention given the limited resources available for HIV programmes (Ekwunife et al., 2021, p. 2). The study aimed to evaluate the cost-effectiveness of an incentive-based intervention on the health outcomes of adolescents living with HIV in Anambra State, Nigeria (Ekwunife et al., 2021, p. 3). The primary outcome was the percentage change in the number of participants with an undetected viral load (VL) of <20 copies/ml, between the intervention and control arms in the 12th month. The secondary outcomes were adherence to ART and hospital appointments, CD4+ count, and retention in care.

The study had two arms - an intervention arm and a comparison (control) arm. The intervention arm received conditional economic incentives and motivational interviews, while the control arm received only the routine standard-of-care treatment. The targeted population was adolescents aged 10-19 years (Ekwunife et al., 2021, p. 3). The conditional economic incentives for the intervention arm were cash rewards of US$5.6 when the viral load was <20 copies/ml for the first 3 months, US$2.8 if the viral load remained suppressed for the subsequent 3 months and the following 6 months, and then US$5.6 if the VL remained <20 copies/ml for another 1 year (Ekwunife et al., 2021, p. 3).

The costs and efficacy of the intervention were determined based on the 2019 base year. The cost-effectiveness of the intervention over the standard of care was assessed using the incremental cost-effectiveness ratio (ICER) index, expressed as cost per additional patient who achieved an undetectable VL. The study found the ICER of the intervention compared to the standard of care as US$1419 per additional patient with undetected VL and concluded that it was not cost-effective based on Woods et al. (2016) recommendation of ≤US$1137 (i.e. 51% of the GDP per capita of Nigeria in 2019) per QALYs gained. The ICER threshold range for low- and medium-income countries is 1-51% of GDP per capita (Woods et al. 2016). The authors however, pointed out that reducing the number of VL and CD4 tests by ≥1 in the intervention arm will make it cost-effective.

2.2. Drummond’s checklist critical appraisal of the study 

Using the Drummond 10-question checklist (Appendix 1), the study was well conducted as a c-RCT, with a clear aim (Doran, 2010; Drummond, 1987). The primary and secondary outcomes were well outlined to enable the identification of inputs of effectiveness (efficacy of intervention) and costs, and the conduct of the cost-effectiveness analysis (CEA). The costs and effects were activity-based and were appropriately identified and obtained from the right sources. The financial incentives used were based on the protocol, although other incentives such as free hospital meals/snacks, food items, household gift items, and socio-ecological skills would have been possible.

As acknowledged by Ekwunife and colleagues, studies have shown that cash incentives are not sustainable in the long run and usually do not produce a long-lasting behavioural change effect (Ekwunife et al., 2021, p. 9). A “do nothing” alternative was not considered, probably because HIV conditions require care and treatment to achieve and maintain viral suppression in PLHIV and prevent progression to AIDS. Thus, the control arm received the standard of care without any incentives. The targeted adolescent population was not stratified into sub-groups by sex, age, location, or socioeconomic status after the cluster-randomisation. The protocol reflected what happens in regular practice when funding is provided for identified activities. Costs were adjusted to 2019 prices using the implicit price deflators - gross domestic product (GDP) deflators. There was no specific justification for the base year other than the year of study completion as specified in the protocol. An in-depth interview (IDI) was used to assess the perception of effectiveness and the feasibility (generalizability) of the intervention in hospitals in Nigeria from health care providers’ perspectives.

2.3. Biases and weaknesses in the study

The outcome of the study may have been weakened by some factors such as sample size, omission of utility inputs and some of the shared resources in the calculation of CEA, and professional biases of IDI respondents. Limitations and potential bias may have arisen from cost variation between centers, small sample sizes, and selected measures of effectiveness (primary and secondary outcomes). The sample size was inadequate, which affected baseline viral suppression data between both arms, and this may have caused effect modification (Ekwunife et al., 2021, p. 9). Long-term costs and consequences or extended CEA were generally not considered. The measured effectiveness was only restricted to the primary and secondary outcomes, which did not include utility inputs such as quality-adjusted life years (QALYs) gained measured by Life-5 Dimensions (EQ-5D™) instrument, and disability-adjusted life years (DALYs) averted (Alfirevic et al., 2016). This affected the range of the costs and effects analysed. The IDI presented only the viewpoints of the healthcare providers (Doctors, Pharmacists, Nurses, and Medical Laboratory Scientists) and did not cover the perspective of other relevant parties such as the patients and community. Furthermore, capital costs covering hospital facilities (building and equipment), data collection costs, and indirect costs from patients and families were excluded (Ekwunife et al., 2018, p. 6). Only operating costs covering items or components of the intervention (laboratory investigations, personnel costs for motivational interviewing, economic incentives, inpatient/outpatient costs, phone calls, and transportation) were included in the CEA (Ekwunife et al., 2021, p. 4-5). The study did not specify the use of joint resources or shared costs, and no identified cost item was specified in the protocol that was omitted from measurement. Costs that did not reflect market values were also not identified or included.

The sources of resources were justified, and the costs were activity-based. Personnel costs were based on the salaries of hospital staff, while costs of medications (ART) and consumables were based on Global Fund Pooled Procurement Mechanism Reference Pricing for ART, and the buyer’s median price of the International Medical Products Price Guide, respectively. Other costs were obtained directly from the hospital (out/in-patient cost), and activities (laboratory tests, phone calls, transportation) or as provided by previous survey studies (Ekwunife et al., 2021, p. 3). All costs were adjusted to the 2019 base year. The analysis did not include discounting or the use of discount rates, because long-term projections were not considered.

The valuation of effects was appropriately done for a CEA. The study did not focus on the allocative efficiency question, which would have at best been evaluated by cost-benefit analysis, but on the technical efficiency or feasibility of the intervention. The effectiveness measures were based on the percentage of participants with viral suppression of ≤20 copies/ml, which is appropriate for incremental cost-effectiveness analysis (ICEA).

The statistical analysis was conducted at a 95% confidence interval (CI) with available patient data. The % difference between both arms in participants with undetected viral loads was statistically determined as 11.7% while it was 8.9% after adjusting for participants who changed regimen to a Dolutegravir-based combination. The intervention's incremental cost-effectiveness ratio (ICER) compared to the standard of care was US$1419 per additional patient with an undetected viral load. A sensitivity test conducted by varying the cost elements over +/-25% did not translate to positive cost-effectiveness of the intervention. The sensitivity test indicated that the intervention was not worthwhile based on Woodset al. (2016) ICER threshold of US$1137 per QALYs for Nigeria. Only a reduction in the number of tests for VL or CD4 in the intervention arm could improve the cost-effectiveness of the intervention (Ekwunife et al., 2021, p.5 and 8). 

3. Discussion

The inference reached by the authors seemed appropriate and was based on the incremental cost-effectiveness ratio (ICER) index, which was interpreted intelligently with reference to Woods et al. (2016, p. 933) percent GDP per capita-based cost-effectiveness threshold (CET). The authors also discussed the results in the context of similar studies and found to align (Ekwunife et al., 2021, p. 9). Opportunities for methodical modification were identified, for instance, the use of skill acquisition incentives instead of economic (financial) incentives for a more sustainable outcome. Study limitations were identified as inadequate sample size, the significant difference in baseline viral suppression between the arms, exclusion of utility benefits in terms of QALYs, exclusion of some costs (capital and data collection), and lack of inclusiveness in the IDI. The generalizability of the intervention to other hospital settings in Nigeria was, however, under-discussed. Capacity building for client-centered counseling skills and increased remuneration of the team of dedicated care providers were identified as factors for successful implementation in real-life settings. Ethical issues of equity and equality among individuals in the population were unexpectedly not discussed.

The study established that in real-life scenarios, other excluded costs may arise. Additionally, substituting economic incentives with social incentives, such as skill acquisition, may reduce costs in the long run, but more studies will be needed to evaluate their cost-effectiveness. The study addressed issues of technical efficiency but not allocative efficiency because it did not compare it to another intervention. A projected long-term CEA may indicate better cost-effectiveness in comparison with similar studies for allocative efficiency decisions.

The study by Ekwunife et al. (2021) is similar in objective and scope to the study by Tozan et al. (2019) on the family economic empowerment intervention through BRIDGES and BRIDGES-plus programme, an incentives-based intervention, targeted at adolescents orphaned by HIV/AIDS in Uganda. While Ekwunife’s intervention was not cost-effective with an ICER of US$1419, Tozan’s Bridges and Bridges-plus intervention with an ICER of US$289 was adjudged cost-effective. However, the different conclusions from the two studies may have been due to approaches to cost items identification and inclusion as well as cost valuation. The stratification of participants into sub-groups in Tozan’s evaluation may also have affected the CEA and ICERs obtained.

4. Implication

The intervention in Ekwunife et al. (2021) study was not cost-effective based on recommended thresholds and therefore, may not appeal to policymakers for population rollout unless other considerations are involved. Unfortunately, the long-term projection of effectiveness, and other measures of effectiveness, for instance, utility measures such as QALYs gained and DALYs averted, the impact on care providers, family, and associates, are not considered in CEA. The cost sensitivity from the number of laboratory tests, which could potentially lower the ICER to ≤US$1086, indicated that the study could be easily modified to become cost-effective. The potential net benefits accrued from QALYs (and/or DALYs), and from other related sectors, could add to overall net benefits in CUA and CBA for policy decisions.

A cross-sectoral cost and benefits comparison involving sectors outside health is always a challenge in CEA, hence CEA analysis alone may not present the required economic evaluation framework needed for an appropriate policy decision (Cohen and Reynolds, 2008; Turner et al., 2021, p. 10-13). A combination of analysis and ethical consideration is usually needed for an effective policy decision (Vlaev et al., 2019). For instance, amidst scarce resources, the question of equity (and equality) among social-demographic gradients is also a necessary consideration in selecting programmes to be implemented (Sassi et al., 2001, p. 19-21). Studies have indicated that economic incentives do not always produce a long-lasting behavioural change effect in young people and have to be supplemented with other social incentives for sustainability (Kavanagh et al., 2010). Moreover, the ethical issue of equity, personal preferences, and socioeconomic status are determinant factors in the effectiveness of incentives as income levels and personal preferences determine the perceived value of financial incentives to an individual. Hence, a more tailored incentive scheme, which may not be financial, could be more effective (Vlaev et al., 2019). A good alternative to the economic incentives used by Ekwunife et al. (2021) could be social-ecological incentives which can be material supports, social skills, and industrial-skills acquisition such as information technology communication (ICT), fashion designing, household consumer products (soaps and detergents, candles, confessionary) production, catering, baking, public speaking, community mobilization, sports, etc (Mercy Corps, 2020). These social and industrial skills, which are more population-goals specific or values-oriented, may cost a little more but will usually produce long-lasting behavioural change effects, and are more cost-effective in an extended CEA (Durantini and Albarracín, 2009; Kullgren et al., 2016).

5. Conclusion

The challenge of HIV/AIDS programme adherence among adolescents in sub-Saharan is a serious public health issue. Several incentive programmes have been developed and implemented to promote the uptake of and adherence to interventions. The cost-effectiveness and sustainability of these programmes amidst declining financial allocations are important considerations for programmes selection and implementation among donors and policymakers. Hence, Ekwunife et al. (2021) examined the cost-effectiveness of an incentives-based HIV intervention among adolescents in Anambra State of Nigeria. The study showed that the intervention was not cost-effective based on the recommended ICER threshold and could become cost-effective if the number of laboratory tests for viral load and CD4 were reduced to ≤3. The study only considered the costs of activities and did not consider the shared costs, capital costs, and patient/family personal costs. The effectiveness measures did not include QALYs gained, DALYs averted, and social benefits from related sectors, such as, averted transmissions and deaths, lost manhours, etc. These excluded measures may have added to the cost-ineffectiveness and limitation of the study. Although the study was similar to that by Tozan et al. (2019), the computation of costs and effectiveness differs significantly due to the disaggregation of participants into subgroups in the latter. This may have influenced the “cost-effective” conclusion of Tozan’s study. Ethical issues of accessibility from the perspective of equity and socioeconomic status are important factors that can influence policymakers’ decisions, irrespective of the CEA. For programme long-term sustainability, material and socio-ecological incentives may be a more cost-effective alternative intervention. The Drummond checklist (Appendix 1) effectively identified and discussed the strengths and weaknesses of the evidence by Ekwunife et al. (2021), which could be helpful in policy decision-making, prioritizing HIV/AIDS programmes, and guiding future research directions.

Acknowledgment: The author acknowledges the positive impact of the University of Suffolk M.Sc. Public Health programme under which the manuscript was primarily developed.

Conflict of Interest: There is no conflict of interest. The author has no specific financial or material interest in developing the manuscript other than to contribute to scientific knowledge on the approach to HIV/AIDS programmes selection based on cost-effectiveness considerations. There was no specific funding from any funder.

Ethical Approval and Consent: Ethical approval and participants’ consent were not applicable because the study did not include any primary data or participants.

Sources of funds: There was no specific funding for the development of this article.

Author Contribution: HOE conceptualized, conducted the literature review, and developed the manuscript.

Supplementary materials: Appendix 1: Drummond 10-question checklist assessment of Ekwunife et al. (2021).

Declaration of Generative AI and AI-assisted Technologies: This study has not used any generative AI tools or technologies in the preparation of this manuscript.