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Extent to which low-level use of antiretroviral treatment could curb the AIDS epidemic in sub-Saharan Africa |
Wood E, Braitstein P, Montaner J S, Schechter M T, Tyndall M W, O'Shaughnessy M V, Hogg R S |
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Record Status This is a critical abstract of an economic evaluation that meets the criteria for inclusion on NHS EED. Each abstract contains a brief summary of the methods, the results and conclusions followed by a detailed critical assessment on the reliability of the study and the conclusions drawn. Health technology Anti-retroviral treatment in sub-Saharan Africa.
Economic study type Cost-effectiveness analysis.
Study population Pregnant HIV-1-positive women and neonates or non-pregnant HIV-1 positive adults, depending on the scenario, in South Africa.
Setting A hospital and primary care clinics. The study was set in South Africa.
Dates to which data relate Effectiveness and resource use data were collected from studies published between 1998and 2000. Cost data were collected from a 2000 source. The price year was 2000.
Source of effectiveness data Effectiveness data were derived from a review of the literature.
Modelling A 5-year model was used to determine the impact of the four anti-retroviral scenarios on the HIV-1 epidemic. Spectrum's AIDS impact model was used to adjust population projections for current and projected HIV-1-associated mortality.
Outcomes assessed in the review The review assessed population projections, life expectancy, age distribution of non-HIV-1-related mortality, fertility rates, adult HIV-1 prevalence, perinatal transmission rates, progression from HIV-infection to AIDS, mortality rates, and efficacy of anti-retroviral treatment.
Study designs and other criteria for inclusion in the review Study designs and other criteria for inclusion were not reported in the review.
Sources searched to identify primary studies The sources searched to identify primary studies were not reported.
Criteria used to ensure the validity of primary studies Criteria used to ensure the validity of primary sources were not reported.
Methods used to judge relevance and validity, and for extracting data Summary statistics from individual studies.
Number of primary studies included At least 9 studies were included.
Methods of combining primary studies A narrative method was used.
Investigation of differences between primary studies An investigation of differences between primary studies was not reported.
Results of the review The perinatal transmission rate was set at 30%. Adult elapsed time from HIV-1 infection to AIDS was normally distributed, with a median of 8 years and a SD of 3.5 years, as was the duration from AIDS to death, with a median of 1 year. 50% of HIV-1 positive infants, infected at birth or during breastfeeding, developed AIDS after 2 years, with 95% developing AIDS by 6 years after infection. Anti-retroviral treatment reduced HIV-1 transmission in the range of 37% to 52%. Anti-retroviral treatment increased life expectancy by 6 years among adults. The number of HIV-1 positive pregnant women was normally distributed with a standard deviation of 20,000. 25% of HIV-1 positive South Africans would access anti-retroviral treatment per year. The number of HIV-1 infected adults in South Africa was normally distributed (SD 1,000,000).
Measure of benefits used in the economic analysis The number of life years gained was used as the measure of benefits.
Direct costs The authors did not report whether direct costs were discounted, although the time horizon for the study was 5 years. Quantities and costs were not reported separately. Direct costs reflected direct drug costs of anti-retroviral provision in all scenarios. The quantity/cost boundary adopted was that of the health service. The estimation of quantities and costs was based on actual data. Estimates of drug costs reflect the UN-brokered preferential pricing strategy. The price year was 2000.
Statistical analysis of costs The cost of a short course of prophylaxis was assumed to have a right-skewed Weibull distribution. The annual cost of triple combination treatment was assumed to be normally distributed.
Indirect Costs Indirect costs were not included.
Sensitivity analysis Sensitivity analyses were conducted on the impact of anti-retroviral treatment on HIV-1 transmission rates. Monte Carlo simulation was undertaken to examine the effect of the cost of short-course anti-retroviral prophylaxis, the cost of triple-combination treatment, and the number of individuals eligible for treatment.
Estimated benefits used in the economic analysis In scenario 0, the cumulative number of HIV-1 and HIV-1 positive births would be 276,000, the cumulative number of new AIDS cases would be 2,302,000 and the projected life expectancy in 2005 would be 46.6 years.
In scenario 1, the cumulative number of HIV-1 and HIV-1 positive births would be 248,000 (CI: 241,000 - 255,000), the cumulative number of new AIDS cases, would be 2,271,000 and the projected life expectancy in 2005 would be 46.8 years.
In scenario 2, the cumulative number of HIV-1 and HIV-1 positive births would be 193,000 (CI: 172,000 - 213,000), the cumulative number of new AIDS cases would be 2,208,000 and the projected life expectancy in 2005 would be 47.2 years.
In scenario 3, the cumulative number of HIV-1 and HIV-1 positive births would be 166,000 (CI: 138,000 - 193,000), the cumulative number of new AIDS cases would be 2,177,00, and the projected life expectancy in 2005 would be 47.5 years.
In scenario 4, the cumulative number of HIV-1 and HIV-1 positive births would be 276,000, the cumulative number of new AIDS cases would be 1,871,000 (CI: 1,583,000 - 2,190,000), and the projected life expectancy in 2005 would be 49.7 years (CI: 47.4 - 51.9).
Cost results In scenario 1, total drug costs were $1,838,000 (CI: 1,094,000 - 3,141,000) and the proportion of per-person health care expenditure was less than 0.001%.
In scenario 2, total drug costs were $5,514,000 (CI: 3,293,000 - 9,408,000) and the proportion of per-person health care expenditure was less than 0.001%.
In scenario 3, total drug costs were $52,160,000 (CI: 31,087,000 - 88,645,000) and the proportion of per-person health care expenditure was less than 0.001%.
In scenario 4, total drug costs were $19,074,750,000 (CI: 16,189,525,000 - 22,033,718,000) and the proportion of per-person health care expenditure was 12.5%.
Synthesis of costs and benefits The cost per life year gained was $19,000 (CI: 11,000 - 32,000) in scenario 1, $19,000 (CI: 11,000 - 32,000) in scenario 2, $133,000 (CI: 79,000 - 226,000) in scenario 3, and $15,000,000 (CI: 12,700,000 - 17,300,000) in scenario 4.
Authors' conclusions Although there are barriers to widespread HIV-1 treatment, limited use of anti-retrovirals could have an immediate and substantial impact on South Africa's AIDS epidemic.
CRD COMMENTARY - Selection of comparators A justification was given for the comparators used, namely currently available treatment scenarios. The user of this database, should decide if these health technologies are relevant to their setting.
Validity of estimate of measure of benefit The authors did not state whether a systematic review of the literature had been undertaken. More details could have been provided with respect to the methods and conduct of the review. Effectiveness estimates were derived credibly from primary studies. Estimation of benefits was obtained directly from the effectiveness analysis.
Validity of estimate of costs Not all categories of costs relevant to the perspective adopted were included in the analysis, since personnel costs were not estimated. Quantities and costs were not reported separately. Sensitivity analyses were reported on costs. Costs were used to proxy prices. The price year was reported.
Other issues The authors did make appropriate comparisons of their findings with those from other studies and the issue of generalisability to other settings was addressed. The authors did not present their results selectively. The study enrolled women and infants at risk from HIV-1 infection and this was reflected in the authors' conclusions. The authors did not consider the cost implications of investment in infrastructure and human resources in order to be able to provide treatment. The additional life expectancy associated with triple-combination treatment was uncertain. Additional benefits accruing from the use of anti-retroviral treatment such as reduced sexual transmission were not accounted for. Several assumptions with respect to HIV-1 prevalence and the effect of short-course antiretrovirals on HIV-1 infection rates had to be made.
Implications of the study There are major barriers to the widespread provision of anti-retroviral therapy in South Africa, including limited health care infrastructure and drug costs.
Source of funding Supported by the National Health Research Development Program of Health Canada through a National Health Research Scholar Award to R S Hogg and by the Medical Research Council through a Senior Scientist award to M T Schechter. E Wood and P Braitstein are supported through the British Columbia Health Research Foundation and the Canadian Health Services Research Foundation.
Bibliographic details Wood E, Braitstein P, Montaner J S, Schechter M T, Tyndall M W, O'Shaughnessy M V, Hogg R S. Extent to which low-level use of antiretroviral treatment could curb the AIDS epidemic in sub-Saharan Africa. Lancet 2000; 355: 2095-2100 Indexing Status Subject indexing assigned by NLM MeSH Africa South of the Sahara /epidemiology; Anti-HIV Agents /economics /therapeutic use; Demography; Disease Outbreaks /prevention & Female; Forecasting; HIV Infections /epidemiology /prevention & HIV-1; Humans; Infectious Disease Transmission, Vertical /prevention & Life Expectancy; Life Tables; Male; Models, Theoretical; Pregnancy; Prevalence; control; control; control AccessionNumber 22000008192 Date bibliographic record published 28/02/2001 Date abstract record published 28/02/2001 |
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