The cost-effectiveness of HIV testing: accounting for differential participation rates
Paltiel A D, Kaplan E H
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
HIV testing.
Type of intervention
Screening.
Economic study type
Cost-effectiveness analysis.
Study population
A hypothetical cohort of HIV-infected and uninfected individuals.
Setting
Hospital. The economic study was carried out in New Haven, Connecticut, USA.
Dates to which data relate
The main effectiveness data were taken from national surveillance surveys andseroprevalence studies conducted between 1988 and 1994. Resource and cost data were not explicitly provided as costs were expressed in terms of a cost penalty adjuster which was dependent on the prevalence in the study population.
Source of effectiveness data
Estimates of differences in infected and uninfected individuals' response to screening interventions, HIV-prevalence rate and rates at which people seek testing services on their ownwere derived from reviews of national surveillance surveys and previously completed seroprevalence studies.
Modelling
A model of HIV screening was used to evaluate the marginal impact of a new programme of screening.
Outcomes assessed in the review
The outcomes assessed were theHIV-prevalence rate and rates at which people seek testing services on their own.
Study designs and other criteria for inclusion in the review
National surveillance surveys and previously completed seroprevalence studies were included in the analysis. The inclusion/exclusion criteria were not stated.
Sources searched to identify primary studies
Not stated.
Criteria used to ensure the validity of primary studies
Not stated.
Methods used to judge relevance and validity, and for extracting data
Not stated.
Number of primary studies included
7 primary studies were included in the review.
Methods of combining primary studies
Narrative.
Investigation of differences between primary studies
Not stated even though it would have been applicable.
Results of the review
The seroprevalence rate for the general population in the US was estimated to be 0.5%. The rates at which people seek HIV testing services on their own were estimated to be ten times higher among HIV-infected people (0.5% versus 5%).
Measure of benefits used in the economic analysis
Estimates of the number of new cases of infection identified and the incremental change in new cases detected were given as the measures of benefit.
Direct costs
HIV screening costs were included in the analysis although they were not explicitly given. The price year was therefore not stated.
Statistical analysis of costs
Not stated.
Currency
US dollars ($).
Sensitivity analysis
A one-way sensitivity analysis was performed on the prevalence of infection and the participation change parameter in relation to the penalty term.
Estimated benefits used in the economic analysis
The penalty term was estimated to be greatest at low population prevalence of infection and participation. Estimates of the number of new cases of infection identified and the incremental change in new cases detected were not stated.
Cost results
The economic cost per test performed and the expected incremental costs of a new screening intervention were not stated.
Synthesis of costs and benefits
A synthesis of the estimated benefits and costs was not given. An incremental analysis was not performed.
Authors' conclusions
Voluntary HIV screening programmes may incur prohibitive costs by over-recruiting people at little risk of infection. Failure to account for differential participation can result in over-optimistic cost-effectiveness estimates. However, the relevance of this result is overwhelmed by what is assumed about the benefits conferred to uninfected people by HIV screening.
CRD COMMENTARY - Selection of comparators
The choice of comparator is clear. Differences exist in how infected and uninfected individuals respond to screening interventions. The requirement for a cost-effectiveness analysis, which accounted for these differences, was identified.
Validity of estimate of measure of benefit
The validity of the study results is uncertain on the grounds that no detailed benefits/costs were reported. Rather, the results were expressed in a penalty term which confirmed that screening low prevalence populations would involve greater costs than screening high prevalence populations and that the penalty term was sensitive to the participation change parameter. The data have not been used selectivelyto assess the impact of differences in participation rates between infected and uninfected individuals on estimates of the cost-effectiveness of HIV screening.
Validity of estimate of costs
The way in which the study was conducted makes it difficult to judge the validity of costs.
Other issues
The issue of generalisability to other settings was not addressed. However, appropriate comparisons were made with other studies. The results do not appear to have been presented selectively although interpreting them is rather difficult due to the unusual approach to economic evaluation used.
Source of funding
None stated.
Bibliographic details
Paltiel A D, Kaplan E H. The cost-effectiveness of HIV testing: accounting for differential participation rates. Medical Decision Making 1997; 17(4): 490-495
Comment in: Medical Decision Making 1997;17(4):495-7.
Indexing Status
Subject indexing assigned by NLM
MeSH
Cost-Benefit Analysis; Decision Support Techniques; HIV Infections /economics /epidemiology /prevention & HIV Seroprevalence; Health Policy; Humans; Mass Screening /economics; Models, Econometric; United States /epidemiology; control