Study design and the estimation of the size of key populations at risk of HIV: lessons from Viet Nam

The Cost of Providing Comprehensive HIV Services to Key Populations: An Analysis of the LINKAGES Program in Kenya and Malawi

INTRODUCTION

Timely data on HIV service costs are critical for estimating resource needs and allocating funding, but few data exist on the cost of HIV services for key populations (KPs) at higher risk of HIV infection in low- and middle-income countries. We aimed to estimate the total and per contact annual cost of providing comprehensive HIV services to KPs to inform planning and budgeting decisions.

METHODS

We collected cost data from the Linkages across the Continuum of HIV Services for Key Populations Affected by HIV (LINKAGES) program in Kenya and Malawi serving female and male sex workers, men who have sex with men, and transgender women. Data were collected prospectively for fiscal year (FY) 2019 and retrospectively for start-up activities conducted in FY2015 and FY2016. Data to estimate economic costs from the provider's perspective were collected from LINKAGES headquarters, country offices, implementing partners (IPs), and drop-in centers (DICs). We used top-down and bottom-up cost estimation approaches.

RESULTS

Total economic costs for FY2019 were US$6,175,960 in Kenya and US$4,261,207 in Malawi. The proportion of costs incurred in IPs and DICs was 66% in Kenya and 42% in Malawi. The costliest program areas were clinical services, management, peer outreach, and monitoring and data use. Mean cost per contact was US$127 in Kenya and US$279 in Malawi, with a mean cost per contact in DICs and IPs of US$63 in Kenya and US$104 in Malawi.

CONCLUSION

Actions undertaken above the service level in headquarters and country offices along with those conducted below the service level in communities, comprised important proportions of KP HIV service costs. The costs of pre-service population mapping and size estimation activities were not negligible. Costing studies that focus on the service level alone are likely to underestimate the costs of delivering HIV services to KPs.

Estimating the cost of HIV services for key populations provided by the LINKAGES program in Kenya and Malawi

BACKGROUND

Data remain scarce on the costs of HIV services for key populations (KPs). The objective of this study was to bridge this gap in the literature by estimating the unit costs of HIV services delivered to KPs in the LINKAGES program in Kenya and Malawi. We estimated the mean total unit costs of seven clinical services: post-exposure prophylaxis (PEP), pre-exposure prophylaxis (PrEP), HIV testing services (HTS), antiretroviral therapy (ART), sexually transmitted infection (STI) services, sexual and reproductive health (SRH) services, and management of sexual violence (MSV). These costs take into account the costs of non-clinical services delivered alongside clinical services and the pre-service and above-service program management integral to the LINKAGES program.

METHODS

Data were collected at all implementation levels of the LINKAGES program including 30 drop-in-centers (DICs) in Kenya and 15 in Malawi. This study was conducted from the provider's perspective. We estimated economic costs for FY 2019 and cost estimates include start-up costs. Start-up and capital costs were annualized using a discount rate of 3%. We used a combination of top-down and bottom-up costing approaches. Top-down methods were used to estimate the costs of headquarters, country offices, and implementing partners. Bottom-up micro-costing methods were used to measure the quantities and prices of inputs used to produce services in DICs. Volume-weighted mean unit costs were calculated for each clinical service. Costs are presented in 2019 United States dollars (US$).

RESULTS

The mean total unit costs per service ranged from US$18 (95% CI: 16, 21) for STI services to US$635 (95% CI: 484, 785) for PrEP in Kenya and from US$41 (95% CI: 37, 44) for STI services to US$1,240 (95% CI 1156, 1324) for MSV in Malawi. Clinical costs accounted for between 21 and 59% of total mean unit costs in Kenya, and between 25 and 38% in Malawi. Indirect costs-including start-up activities, the costs of KP interventions implemented alongside clinical services, and program management and data monitoring-made up the remaining costs incurred.

CONCLUSIONS

A better understanding of the cost of HIV services is highly relevant for budgeting and planning purposes and for optimizing HIV services. When considering all service delivery costs of a comprehensive HIV service package for KPs, costs of services can be significantly higher than when considering direct clinical service costs alone. These estimates can inform investment cases, strategic plans and other budgeting exercises.

Summarizing methods for estimating population size for key populations: a global scoping review for human immunodeficiency virus research

BACKGROUND

Estimating the population sizes of key populations(people who inject drugs, men who have sex with men, transgender persons, and commercial sex workers) is critical for understanding the overall Human Immunodeficiency Virus burden. This scoping review aims to synthesize existing methods for population size estimation among key populations, and provide recommendations for future application of the existing methods.

METHODS

Relevant studies published from 1st January 2000 to 4th August 2020 and related to key population size estimation were retrieved and 120 of 688 studies were assessed. After reading the full texts, 81 studies were further excluded. Therefore, 39 studies were included in this scoping review. Estimation methods included five digital methods, one in-person method, and four hybrid methods.

FINDING

We summarized and organized the methods for population size estimateion into the following five categories: methods based on independent samples (including capture-recapture method and multiplier method), methods based on population counting (including Delphi method and mapping method), methods based on the official report (including workbook method), methods based on social network (including respondent-driven sampling method and network scale-up method) and methods based on data-driven technologies (Bayesian estimation method, Stochastic simulation method, and Laska, Meisner, and Siegel estimation method). Thirty-six (92%) articles were published after 2010 and 23 (59%) used multiple methods. Among the articles published after 2010, 11 in high-income countries and 28 in low-income countries. A total of 10 estimated the size of commercial sex workers, 14 focused on men who have sex with men, and 10 focused on people who inject drugs.

CONCLUSIONS

There was no gold standard for population size estimation. Among 120 studies that were related to population size estimation of key populations, the most commonly used population estimation method is the multiplier method (26/120 studies). Every method has its strengths and biases. In recent years, novel methods based on data-driven technologies such as Bayesian estimation have been developed and applied in many surveys.