Drug use and sexual risk behaviours among female Russian IDUs who exchange sex for money or drugs.

Countries of the former Soviet Union are experiencing the steepest increases in annual HIV incidence in the world. Over 80% of registered HIV cases in Russia have occurred among intravenous drug users (IDUs), but current conditions set the stage for a heterosexually-transmitted epidemic. IDUs who also trade sex for money or drugs may serve as a conduit, or 'bridge' group, through which HIV could make inroads into the general Russian population. The present study examined the prevalence of sex trading among female Russian IDUs, and further examined drug use, sexual behaviour, and perceived vulnerability in this group. Female IDUs (n=100) in St Petersburg, Russia participated; 37% reported a history of sex trading. This group reported a mean of 49.5 male sexual partners in the previous month and an average of 15.4 unprotected vaginal intercourse acts in the previous 30 days. A significant minority (44%) also reported sharing injection equipment with others. Mathematical models to calculate risk estimates for HIV seroconversion indicated that participants were at significant risk of contracting HIV and infecting sexual partners. Despite significant rates of risk behaviours, most participants perceived themselves to be at little risk of contracting HIV. Effective HIV prevention programmes targeted at this group are urgently needed and are likely to be a cost-effective step in curtailing the spread of HIV in the region.

All STDs are not created equal: an analysis of the differential effects of sexual behaviour changes on different STDs.

The same sexual behaviours that transmit HIV are implicated in the transmission of certain other STDs, including chlamydia, gonorrhoea, and syphilis. Consequently, it is often assumed that preventive methods that are effective against HIV should be equally effective against other STDs. The purpose of this study was to examine this assumption. We applied a mathematical model of HIV/STD transmission to empirical data from a large HIV prevention intervention that stressed sexual behaviour change. We modelled the effects of two behavioural strategies - reducing the number of sex partners and increasing condom use-on the proportionate change in intervention participants' cumulative risk of acquiring HIV or a highly-infectious STD, such as gonorrhoea. The results of this modelling exercise indicate that decreasing the number of partners is a more effective strategy for reducing STD risk than it is for HIV risk. In contrast, condoms are somewhat more effective at reducing the cumulative transmission risk for HIV than for highly infectious STDs. The protection provided by condoms for multiple acts of intercourse critically depends on the infectiousness of the STD. The results of this study suggest caution in extrapolating from one STD to another, or from one behavioural risk reduction strategy to another.

Sexual risk compensation and HIV/STD transmission: empirical evidence and theoretical considerations.

This study was conducted to answer the question, "Are sexual risk behaviors subject to compensation?" For example, do people who increase their use of condoms compensate for this reduction in human immunodeficiency virus and sexually transmitted disease (HIV/STD) risk by engaging in more overall acts of intercourse or by having sex with more partners than before? Utilizing the HIV prevention literature, studies in which participants demonstrated sexual risk compensation were identified. A simple HIV/STD transmission model was applied to these data to determine whether compensation produced a net increase in HIV/STD risk, despite positive changes in one or more aspects of sexual behavior. Although a number of studies were found in which there were simultaneous increases in condom use and the overall number of acts of intercourse, in none of these instances was there an overall increase in HIV/STD risk. Moreover, none of these studies reported concomitant increases in the number of sex partners. Extensive modeling exercises also were conducted to determine the theoretical conditions under which compensation would produce a net increase in risk. The results of the modeling exercise indicated that relatively small increases in overall sexual activity could be sufficient to offset risk-reduction gains due to increased condom use in populations in which baseline condom use is very low. In sum, although sexual risk compensation occurs, no empirical evidence was found that this compensation is sufficient to offset reductions in risk due to greater condom use, despite the theoretical plausibility of this scenario.

Influence of a partner's HIV serostatus, use of highly active antiretroviral therapy, and viral load on perceptions of sexual risk behavior in a community sample of men who have sex with men.

OBJECTIVE: To assess the perceptions of gay and bisexual men concerning the risk of HIV transmission through various sexual practices with a new sex partner depending on that partner's disclosed HIV status, antiretroviral treatment status, and viral load. METHODS: Study participants read four different scenarios describing sexual situations with a new partner and rated each scenario for risk of HIV transmission. HIV status and antiretroviral treatment status disclosed by the new sex partner were varied across four scenarios: unknown HIV status; HIV-negative; HIV-positive and not taking highly active antiretroviral therapy (HAART); and HIV-positive and taking HAART with an undetectable viral load. RESULTS: Study participants were 472 men attending a gay pride festival who reported that they were HIV-negative. Eighty-nine percent of the men were white, and the mean age of the study participants was 35.8 years. Of the four scenarios, sex with an HIV-positive partner not taking HAART was rated as posing the greatest risk. Sex with an HIV-positive partner taking HAART who had an undetectable viral load was not consistently viewed as riskier than sex with an HIV-negative partner or a man with an unknown HIV status. CONCLUSIONS: The current study provides preliminary evidence for the effect of disclosure of HIV serostatus, use of HAART, and the presence of an undetectable viral load on the perceptions of sexual risk for HIV-negative men. The findings suggest that some gay and bisexual men judge risk based on the perceived HIV status of their sex partners and not on the general assumption that all sex partners entail equal risk, as many prevention campaigns have emphasized.

Cost-effectiveness of an HIV prevention intervention for mentally ill adults.

Adults with severe mental illness are at high risk for human immunodeficiency virus (HIV) infection and transmission. Small-group interventions that focus on sexual communication, condom use skills, and motivation to practice safer sex have been shown to be effective at helping mentally ill persons reduce their risk for HIV. However, the cost-effectiveness of these interventions has not been established. We evaluated the cost-effectiveness of a 9-session small-group intervention for women with mental illness recruited from community mental health clinics in Milwaukee, Wisconsin. We used standard techniques of cost-utility analysis to determine the cost per quality-adjusted life year (QALY) saved by the intervention. This analysis indicated that the intervention cost $679 per person, and over $136,000 per QALY saved. When the analysis was restricted to the subset of women who reported having engaged in vaginal or anal intercourse in the 3 months prior to the baseline assessment, the cost per QALY saved dropped to approximately $71,000. These estimates suggest that this intervention is marginally cost-effective in comparison with other health promotion interventions, especially if high-risk, sexual-active women are preferentially recruited.

Probabilistic cost-effectiveness analysis of HIV prevention. Comparing a Bayesian approach with traditional deterministic sensitivity analysis.

In cost-effectiveness analysis, the incremental cost-effectiveness ratio is used to measure economic efficiency of a new intervention, relative to an existing one. However, costs and effects are seldom known with certainty. Uncertainty arises from two main sources: uncertainty regarding correct values of intervention-related parameters and uncertainty associated with sampling variation. Recently, attention has focused on Bayesian techniques for quantifying uncertainty. We computed the Bayesian-based 95% credible interval estimates of the incremental cost-effectiveness ratio of several related HIV prevention interventions and compared these results with univariate sensitivity analyses. The conclusions were comparable, even though the probabilistic technique provided additional information.

Using cost-effectiveness league tables to compare interventions to prevent sexual transmission of HIV.

Cost-effectiveness information is needed to help public health decision makers choose between competing HIV prevention programs. One way to organize this information is in a 'league table' that lists cost-effectiveness ratios for different interventions and which facilitates comparisons across interventions. Herein we propose a common outcome measure for use in HIV prevention league tables and present a preliminary league table of interventions to reduce sexual transmission of HIV in the US. Fifteen studies encompassing 29 intervention for different population groups are included in the table. Approximately half of the interventions are cost-saving (i.e. save society money, in the long run), and three-quarters are cost-effective by conventional standards. We discuss the utility of such a table for informing the HIV prevention resource allocation process and delineate some of the difficulties associated with the league table approach, especially as applied to HIV prevention cost-effectiveness analysis.

A relative risk-based, disease-specific definition of sexual abstinence failure rates.

Sexual abstinence programs have the potential to reduce the incidence of unplanned pregnancies and sexually transmitted diseases (STDs) among adolescents. Effectiveness measures are needed to help researchers assess the impact of sexual abstinence promotion programs on STD and pregnancy rates and to enable comparisons of abstinence effectiveness with other contraception and STD prevention methods. Abstinence "failure rates" have been proposed as one measure of program effectiveness. However, the concept of abstinence failure rates has not been adequately operationalized. The present study examines a novel mathematical framework for estimating abstinence failure rates, both theoretically and empirically. Examples are provided, and the advantages and disadvantages associated with the mathematical model-based approach are discussed.

Economic evaluation of HIV risk reduction intervention in African-American male adolescents.

PURPOSE: To evaluate the cost-effectiveness of a cognitive-behavioral HIV risk reduction intervention for African-American male adolescents that has previously been shown to be effective at reducing sexual risk taking. METHODS: Standard techniques of cost-utility analysis were employed. A societal perspective and a 3% discount rate were used in the main analysis. Program costs were ascertained retrospectively. A mathematical model of HIV transmission was used to translate observed changes in sexual behavior into an estimate of the number of HIV infections the intervention averted. Intervention effects were assumed to last for 1 year. For each infection averted, the corresponding savings in future HIV-related medical care costs and quality-adjusted life years (QALYs) were estimated. The overall net cost per QALY saved (cost-utility ratio) was then calculated. Sensitivity analyses were performed to assess the robustness of the main results. RESULTS: The cost-utility ratio was approximately $57,000 U.S. per QALY saved when training costs were included, and $41,000 U.S. per QALY saved when they were excluded. The intervention appeared substantially more cost-effective when the analysis was restricted to the subgroup of participants who reported being sexually active at baseline. Assumptions about the prevalence of HIV infection and the duration of intervention effectiveness also greatly affected the cost-utility ratio. CONCLUSIONS: The HIV prevention intervention was moderately cost-effective in comparison with other health care programs. Selectively implementing the intervention in high-HIV prevalence communities and with sexually active youth can enhance cost-effectiveness.

Consequences of HIV prevention interventions and programs: spectrum, selection, and quality of outcome measures.

The outcome measures employed in an HIV prevention intervention study should match the research and policy questions at hand. If the question is 'did the intervention work to prevent HIV infection?', then seroincidence data may be insufficient. However, if the question is 'why did the intervention work?', then more detailed behavioral data are necessary (and sometimes behavior change itself is the real goal of an intervention study). Given the wide range of questions asked by HIV prevention policy makers, funders and researchers, a spectrum of outcome measures is needed across HIV prevention intervention studies. These include measures of behavioral determinants, HIV-related risk behaviors, HIV incidence (and other biologic markers), morbidity, mortality, and cost-effectiveness factors (such as cost per quality-adjusted life year saved). In this paper, we review the range of outcome measures used and needed in these intervention studies. Particular attention is paid to the psychometric properties of self-reported behavior change measures of sexual behavior and substance use. Additional emphasis is placed on the role of cost-effectiveness measures in intervention studies. A general framework is proposed for conceptualizing the array of outcome measure possible for any given HIV prevention intervention study.

Prioritization methods for HIV community planning.

Since 1994, community planning groups (CPGs) have played an important role in shaping local HIV prevention efforts. The community planning process requires CPGs to prioritize HIV prevention interventions and unmet needs among at-risk populations. This article describes and compares four prioritization methods: (1) the ranking method, (2) Holtgrave's method, (3) Kaplan's method, and (4) a novel utility-based prioritization method. These methods are compared in terms of effectiveness, efficiency, equity, and political feasibility. The methods described here are meant to assist CPGs in the difficult prioritization task by helping CPG members organize their thoughts in the prioritization process.

Cost-effectiveness of an HIV risk reduction intervention for adults with severe mental illness.

Small-group HIV prevention interventions that focus on individual behavioural change have been shown to be especially effective in reducing HIV risk among persons with severe mental illness. Because economic resources to fund HIV prevention efforts are limited, health departments, community planning groups and other key decision-makers need reliable information on the cost and cost-effectiveness (not solely on effectiveness) of different HIV prevention interventions. This study used an economic evaluation technique known as cost-utility analysis to assess the cost-effectiveness of three related cognitive-behavioural HIV risk reduction interventions: a single-session, one-on-one intervention; a multi-session small-group intervention; and a multi-session small-group intervention that taught participants to act as safer sex advocates to their peers. For men, all three interventions were cost-effective, but advocacy training was the most cost-effective of the three. For women, only the single-session intervention was cost-effective. The gender differences observed here highlight the importance of focusing on gender issues when delivering HIV prevention interventions to men and women who are severely mentally ill.

When is an HIV infection prevented and when is it merely delayed?

HIV prevention programs are typically evaluated using behavioral outcomes. Mathematical models of HIV transmission can be used to translate these behavioral outcomes into estimates of the number of HIV infections averted. Usually, intervention effectiveness is evaluated over a brief assessment period and an infection is considered to be prevented if it does not occur during this period. This approach may overestimate intervention effectiveness if participants continue to engage in risk behaviors. Conversely, this strategy underestimates the true impact of interventions by assuming that behavioral changes persist only until the end of the intervention assessment period. In this article, the authors (a) suggest a simple framework for distinguishing between HIV infections that are truly prevented and those that are merely delayed, (b) illustrate how these outcomes can be estimated, (c) discuss strategies for extrapolating intervention effects beyond the assessment period, and (d) highlight the implications of these findings for HIV prevention decision making.

Cost-threshold analyses of the National AIDS Demonstration Research HIV prevention interventions.

OBJECTIVE: The goal of the multisite National AIDS Demonstration Research (NADR) program was to reduce the sexual and drug injection-related HIV risks of out-of-treatment injection drug users and their sex partners. Previous analyses have established that the NADR interventions were effective at changing participants' risky behaviors. This study was to determine whether the NADR program also was cost-effective. METHODS: Data from eight NADR study sites were included in the analysis. A mathematical model was used to translate reported sexual and injection-related behavior changes into an estimate of the number of infections prevented by the NADR interventions and then to calculate the corresponding savings in averted HIV/AIDS medical care costs and quality-adjusted years of life, assuming United States values for these parameters. Because cost data were not collected in the original NADR evaluation, the savings in averted medical care costs were compared with the cost of implementing a similar intervention program for injection drug users. RESULTS: The eight NADR interventions prevented approximately 129 infections among 6629 participants and their partners. Overall, the NADR program would be cost saving (i.e. provide net economic savings) if it cost less than US$2107 per person and would be cost-effective if it cost less than US$10,264 per person. Both of these estimates are considerably larger than the US$273 per person cost of the comparison intervention. There was substantial cross-site variability. CONCLUSIONS: The results of this analysis strongly suggest that the NADR interventions were cost-saving overall and were, at the very least, cost-effective at all eight sites. In the United States and other developed counties, investments in HIV-prevention interventions such as these have the potential to save substantial economic resources by averting HIV-related medical care expenses among injection drug users.

Sexually transmitted diseases and the increased risk for HIV transmission: implications for cost-effectiveness analyses of sexually transmitted disease prevention interventions.

We estimated the annual number and cost of new HIV infections in the United States attributable to other sexually transmitted diseases (STDs). We used a mathematical model of HIV transmission to estimate the probability that a given STD infection would facilitate HIV transmission from an HIV-infected person to his or her partner and to calculate the number of HIV infections due to these facilitative effects. In 1996, an estimated 5,052 new HIV cases were attributable to the four STDs considered here: chlamydia (3,249 cases), syphilis (1,002 cases), gonorrhea (430 cases), and genital herpes (371 cases). These new HIV cases account for approximately $985 million U.S. in direct HIV treatment costs. The model suggested that syphilis is far more likely than the other STDs (on a per-case basis) to facilitate HIV transmission. This analysis provides a framework for incorporating STD-attributable HIV treatment costs into cost-effectiveness analyses of STD prevention programs.

Hispanic adults' beliefs, attitudes, and intentions regarding the female condom.

The present study used the theory of planned behavior (TPB) (Ajzen, 1985) augmented by AIDS knowledge to investigate factors influencing intentions of Hispanic adults to use the female condom. A total of 146 persons (75 women and 71 men; mean age, 27 years) recruited from community-based organizations completed an anonymous survey regarding intentions to use the female condom with their main sex partner. The TPB model had greater predictive utility for women's, than for men's, female condom use intentions. For men, attitudes and norms did not predict female condom use intentions, but greater AIDS knowledge was related to lower intentions to use the female condom, above and beyond the TPB constructs. Perceived behavioral control, operationalized as self-efficacy, significantly increased the predictive utility of the TPB model for women's female condom use intentions but not for men's. Behavior change strategies to increase female condom use are discussed in light of these findings.

Decision-making in HIV prevention community planning: an integrative review.

Since 1994, the Centers for Disease Control and Prevention has required that the 65 health department grantees that receive funding for HIV prevention interventions engage in a community planning process to involve affected communities in local prevention decision making; to increase the use of epidemiological data to target HIV prevention resources; and to ensure that the planning process takes into account scientific information on the effectiveness and efficiency of different HIV interventions. Local community planning groups are charged with identifying and prioritizing unmet HIV prevention needs in their communities, as well as prioritizing prevention interventions designed to address these needs. Their recommendations, in turn, form the basis for the local health department's request for HIV prevention funding from the Centers for Disease Control and Prevention. Given the community planning process's central role in the allocation of federal HIV prevention funds, it is critical that sound decision-making procedures inform this process. In this article, we review the basics of the community planning prioritization process and summarize the decision-making experiences of community planning groups across the US. We then describe several priority-setting tools and decision analytic models that have been developed to assist in HIV community planning prioritization and discuss their strengths and weaknesses. Finally, we offer suggestions for improving the decision-analytic basis for HIV prevention community planning.