Economic issues in the prevention of vertical transmission of HIV

Assessing the cost of providing a prevention of mother-to-child transmission of HIV/AIDS service in Ethiopia: urban-rural health facilities setting

Background

While local context costing evidence is relevant for healthcare planning, budgeting and cost-effectiveness analysis, it continues to be scarce in Ethiopia. This study assesses the cost of providing a prevention of mother-to-child transmission of HIV/AIDS (PMTCT) service across heterogeneous prevalence (high, low) and socio-economic (urban, rural) contexts.

Methods

A total of 12 health facilities from six regions in Ethiopia were purposively selected from the latest 2012 antenatal sentinel HIV prevalence report. Six health facilities with the highest HIV prevalence (8.1 to 17.3%) in urban settings and six health facilities with the lowest prevalence (0.0 to 0.1%) in rural settings were selected. A micro-costing approach was applied to identify, measure and value resources used for the provision of a comprehensive PMTCT service. The analysis was conducted across different PMTCT service packages. We also estimated national costs in urban and rural contexts.

Results

The average cost per pregnant woman-infant pair per year (PPY) ranged from ETB 6280 (USD 319) to ETB 21,620 (USD 1099) in the urban high HIV prevalence health facilities setting. In rural low HIV prevalence health facilities, the cost ranged from ETB 4323 (USD 220) to ETB 7539 (USD 383).PMTCT service provision in urban health facilities costs more than twice the cost in rural health facilities. The average cost per PPY in an urban setting was more than double the cost in a rural setting due to the higher cost of inputs and possible inefficiencies (although there were a higher number of visits). Consumables (including antiretroviral drugs) and infrastructure were the major cost drivers in both the urban and rural health facilities. Among PMTCT service components, anti-retroviral treatment Option B+ follow-up and counselling accounted for the highest proportion of costs, which ranged from 58 to 72%. Nationally, at the current coverage, the cost of PMTCT service was USD 6 million and USD 3 million in urban and rural settings, respectively.

Conclusions

The analysis suggests that resources used for PMTCT service packages varied across health facilities and HIV prevalence contexts. Providing PMTCT service in the high HIV prevalence urban health facilities costs more than in the rural facilities. Context-specific costing was vital to provide locally sensitive evidence for health service management and priority setting.

Electronic supplementary material

The online version of this article (10.1186/s12913-019-3978-4) contains supplementary material, which is available to authorized users.

Sex-dependent metabolism of nevirapine in rats: impact on plasma levels, pharmacokinetics and interaction with nortriptyline

Nevirapine (NVP) is a non-nucleoside reverse transcriptase inhibitor (NNRTI) widely used in the treatment of human immunodeficiency virus type 1 (HIV-1) and is the first-choice NNRTI during pregnancy. NVP shows a sex dimorphic profile in humans with sex differences in bioavailability, biotransformation and toxicity. In this study, sex differences in NVP metabolism and inhibition of NVP metabolism by the antidepressant nortriptyline (NT) were evaluated using rats as experimental animals. NVP was administered orally to male and female rats and sex differences in plasma levels and pharmacokinetic parameters were analysed. NVP plasma levels were higher in female compared with male rats, and pharmacokinetic parameters such as maximum plasma concentration (C_max), time to C_max (T_max), half-life (t_1/2) and area under the plasma concentration-time curve from the time of dosing to the last measurable concentration (AUC_last) showed ca. 4-, 5-, 7- and 22-fold higher values in female rats. In vitro experiments carried out with hepatic microsomes confirmed slower NVP metabolism in female rats, with a maximum velocity (V_max) 2-fold lower than in male hepatic microsomes. The major metabolite in both sexes was 12-hydroxynevirapine (12-OH-NVP), with the V_max for this metabolite being 15-fold lower in female compared with male rat hepatic microsomes. Inhibition of NVP metabolism by NT was similar in both sexes, with statistically non-significant differences in 50% inhibitory concentration (IC₅₀) values. In summary, NVP is metabolised more slowly in female compared with male rats, but the inhibitory effect of NT is similar in both sexes.

Differences in nevirapine biotransformation as a factor for its sex-dependent dimorphic profile of adverse drug reactions

OBJECTIVES

Nevirapine is widely used for the treatment of HIV-1 infection; however, its chronic use has been associated with severe liver and skin toxicity. Women are at increased risk for these toxic events, but the reasons for the sex-related differences are unclear. Disparities in the biotransformation of nevirapine and the generation of toxic metabolites between men and women might be the underlying cause. The present work aimed to explore sex differences in nevirapine biotransformation as a potential factor in nevirapine-induced toxicity.

METHODS

All included subjects were adults who had been receiving 400 mg of nevirapine once daily for at least 1 month. Blood samples were collected and the levels of nevirapine and its phase I metabolites were quantified by HPLC. Anthropometric and clinical data, and nevirapine metabolite profiles, were assessed for sex-related differences.

RESULTS

A total of 52 patients were included (63% were men). Body weight was lower in women (P = 0.028) and female sex was associated with higher alkaline phosphatase (P = 0.036) and lactate dehydrogenase (P = 0.037) levels. The plasma concentrations of nevirapine (P = 0.030) and the metabolite 3-hydroxy-nevirapine (P = 0.035), as well as the proportions of the metabolites 12-hydroxy-nevirapine (P = 0.037) and 3-hydroxy-nevirapine (P = 0.001), were higher in women, when adjusted for body weight.

CONCLUSIONS

There was a sex-dependent variation in nevirapine biotransformation, particularly in the generation of the 12-hydroxy-nevirapine and 3-hydroxy-nevirapine metabolites. These data are consistent with the sex-dependent formation of toxic reactive metabolites, which may contribute to the sex-dependent dimorphic profile of nevirapine toxicity.

Unit costs for delivery of antiretroviral treatment and prevention of mother-to-child transmission of HIV: a systematic review for low- and middle-income countries

As antiretroviral treatment (ART) for HIV/AIDS is scaled up globally, information on per-person costs is critical to improve efficiency in service delivery and to maximize coverage and health impact. The objective of this study was to review studies on unit costs for delivery of adult and paediatric ART per patient-year, and prevention of mother-to-child transmission (PMTCT) interventions per mother-infant pair screened or treated, in low- and middle-income countries. A systematic review was conducted of English, French and Spanish publications from 2001 to 2009, reporting empirical costing that accounted for at least antiretroviral (ARV) medicines, laboratory testing and personnel. Expenditures were analysed by country-income level and cost component. All costs were standardized to $US, year 2009 values. Several sensitivity analyses were conducted. Analyses covered 29 eligible, comprehensive, costing studies. In the base case, in low-income countries (LIC), median ART cost per patient-year was $US792 (mean: 839, range: 682-1089); for lower-middle-income countries (LMIC), the median was $US932 (mean: 1246, range: 156-3904); and, for upper-middle-income countries (UMIC), the median was $US1454 (mean: 2783, range: 1230-5667). ARV drugs were the largest component of overall ART costs in all settings (64%, 50% and 47% in LIC, LMIC and UMIC, respectively). Of 26 ART studies, 14 reported the drug regimes used, and only one study explicitly reported second-line treatment costs. The second cost driver was laboratory cost in LIC and LMIC (14% and 20%), and personnel costs in UMIC (26%). Two ART studies specified the types of laboratory tests costed, and three studies specifically included above facility-level personnel costs. Three studies reported detailed PMTCT costs, and three studies reported on paediatric ART. There is a paucity of data on the full unit costs for delivery of ART and PMTCT, particularly for LIC and middle-income countries. Heterogeneity in activities costed, and insufficient detail regarding components included in the costing, hampers standardization of unit cost measures. Evaluation of programme-level unit costs would benefit from international guidance on standardized costing methods, and expenditure categories and definitions. Future work should help elucidate the sources of the large variations in delivery unit costs across settings with similar income and epidemiological characteristics.

Preventing mother to child transmission of HIV with highly active antiretroviral treatment in Tanzania--a prospective cost-effectiveness study

Recent guidelines recommend that all HIV-infected women should receive highly active antiretroviral therapy throughout pregnancy and lactation, irrespective of whether or not they need it for their own health. This strategy for prevention of mother to child transmission (PMTCT) of HIV is more effective than the well-established use of single-dose nevirapine, but it is also a more costly alternative. In this economic evaluation, we use a decision model to combine the best available clinical evidence with cost, epidemiological and behavioral data from Northern Tanzania. We find that a highly active antiretroviral therapy-based PMTCT Plus regimen is more cost effective than the current Tanzanian standard of care with single-dose nevirapine. Although PMTCT Plus is roughly 40% more expensive per pregnant woman than single-dose nevirapine, the expected health benefits are 5.2 times greater. The incremental cost effectiveness ratio of the PMTCT Plus intervention is calculated to be 4062 USD per child infection averted and 162 USD per disability adjusted life year.

The cost-effectiveness of directly observed highly-active antiretroviral therapy in the third trimester in HIV-infected pregnant women

BACKGROUND

In HIV-infected pregnant women, viral suppression prevents mother-to-child HIV transmission. Directly observed highly-active antiretroviral therapy (HAART) enhances virological suppression, and could prevent transmission. Our objective was to project the effectiveness and cost-effectiveness of directly observed administration of antiretroviral drugs in pregnancy.

METHODS AND FINDINGS

A mathematical model was created to simulate cohorts of one million asymptomatic HIV-infected pregnant women on HAART, with women randomly assigned self-administered or directly observed antiretroviral therapy (DOT), or no HAART, in a series of Monte Carlo simulations. Our primary outcome was the quality-adjusted life expectancy in years (QALY) of infants born to HIV-infected women, with the rates of Caesarean section and HIV-transmission after DOT use as intermediate outcomes. Both self-administered HAART and DOT were associated with decreased costs and increased life-expectancy relative to no HAART. The use of DOT was associated with a relative risk of HIV transmission of 0.39 relative to conventional HAART; was highly cost-effective in the cohort as a whole (cost-utility ratio $14,233 per QALY); and was cost-saving in women whose viral loads on self-administered HAART would have exceeded 1000 copies/ml. Results were stable in wide-ranging sensitivity analyses, with directly observed therapy cost-saving or highly cost-effective in almost all cases.

CONCLUSIONS

Based on the best available data, programs that optimize adherence to HAART through direct observation in pregnancy have the potential to diminish mother-to-child HIV transmission in a highly cost-effective manner. Targeted use of DOT in pregnant women with high viral loads, who could otherwise receive self-administered HAART would be a cost-saving intervention. These projections should be tested with randomized clinical trials.

Cost-effectiveness of antenatal HIV-testing: reviewing its pharmaceutical and methodological aspects

This paper reviews the pharmacoeconomic aspects of antenatal testing for HIV. HIV is a retrovirus which is transmitted among humans through sexual contact, infected blood or blood products (needle sharing or percutaneous accidents) and from mother to child (vertical transmission). Vertical transmission from the HIV-infected mother can occur in utero during and after delivery, through breastfeeding. Effective interventions available to reduce the risk of vertical transmission include: pharmacotherapy prior, during and after delivery; voluntary caesarean section; and replacing breastfeeding by bottle-feeding [1,2]. The existence of these effective interventions underlies the need to detect yet undiagnosed HIV-infection in pregnancy through antenatal testing. Contemporary pharmacotherapy consists of a combination of three or more antiretroviral drugs, also referred to as highly-active antiretroviral therapy (HAART). For newly detected HIV-infected mothers, the Centers for Disease Control suggests the use of a zidovudine-comprising combination with one other nucleoside analogue reverse transcriptase inhibitor and a protease inhibitor (PI) [3]. As HIV in pregnancy may be asymptomatic, structured antenatal HIV-testing therefore seems to offer an attractive prevention strategy. Two broad types of approaches exist: selective or targeted testing versus universal testing. The availability of effective - but expensive - combination therapies since 1996 has greatly enhanced the importance of pharmacoeconomic assessments in the field of HIV-infection. Treatment of the mother will incur additional costs but will also make any programme more effective. Furthermore, avoiding children becoming infected with HIV will also incur monetary benefits, as children are also being treated with HAART. In summary, the background of antenatal HIV-testing has undergone major changes compared with the early 1990s. This review of the pharmacoeconomics of antenatal HIV-testing followed a systematic approach as it was performed according to prespecified criteria, allowing valid comparisons in methodologies and findings of those studies that have yet been conducted in this area.

Cost-effectiveness of widespread screening for Chlamydia trachomatis

Screening for sexually transmitted diseases is included in routine health care for several infectious agents in many western European countries. Current considerations on extensions of these programs include widespread screening strategies for Chlamydia trachomatis. In women, C. trachomatis infection may lead to sequelae such as infertility and ectopic pregnancy. This paper reviews the goal of screening and subsequent therapy and the available compounds for testing and treating. Furthermore, the current best practice - in particular with respect to economic performance - is discussed, and those factors that most crucially influence the economic profile are described. Illustrations are drawn from recent work in The Netherlands, which may also be representative for other settings.

HIV/AIDS care in KwaZulu-Natal, South Africa: an interview with Dr. Leana Uys. Interviewed by Ellen Giarelli and Linda A. Jacobs

Human suffering from the HIV/AIDS epidemic in Africa has reached unprecedented proportions. In 1998, an estimated 50% of all new infections in sub-Saharan Africa occurred in South Africa; and it is predicted that by the year 2003, South Africa will be experiencing a negative population growth. Besides the toll in human lives, the estimated cost for basic care and prevention services in Africa is 10 times the current expenditure. Three unique factors are critical in the South African HIV/AIDS epidemic: HIV transmission patterns, the effect of this disease on women and children, and the role that traditional healers play in the treatment of HIV/AIDS. In a recent interview, Dr. Leana Uys, an educational leader in the School of Nursing at the University of Natal in Durban, Republic of South Africa, provided an insightful perspective on HIV/AIDS policies and related sociocultural issues that have a direct effect on the HIV/AIDS epidemic. She communicated her personal experiences as well as the experiences of South African nurses working as caregivers, educators, and policy makers with AIDS patients and their families in KwaZulu-Natal.