Cost-effectiveness of tuberculosis screening and observed preventive therapy for active drug injectors at a syringe-exchange program

Inclusion of non-medical interventions in model-based economic evaluations for tuberculosis: A scoping review

BACKGROUND

The economic evaluation of health interventions is important in priority setting. Several guidance documents exist to support the conduct of economic evaluations, however, there is limited guidance for the evaluation of non-medical interventions. For tuberculosis (TB), where equity-deserving groups are disproportionately impacted, assessing interventions aimed at addressing social risk factors is necessary to effectively reduce TB burden.

OBJECTIVE

This scoping review seeks to assess the existing literature on model-based economic evaluations of TB interventions to gauge the extent to which non-medical interventions have been evaluated in low-TB-incidence jurisdictions. As a secondary objective, this review aims to characterize key features of existing economic evaluations of medical and non-medical interventions.

METHODS

A literature search was conducted in the grey literature and MEDLINE, Embase, EconLit, and PsychINFO databases to September 6, 2022 following the Arksey and O'Malley framework. Eligible articles were those that used decision-analytic modeling for economic evaluation of TB interventions in low-TB-incidence jurisdictions.

RESULTS

This review identified 127 studies that met the inclusion criteria; 11 focused on prevention, 73 on detection, and 43 on treatment of TB. Only three studies (2%) evaluated non-medical interventions, including smoking reduction strategies, improving housing conditions, and providing food vouchers. All three non-medical intervention evaluations incorporated TB transmission and robust uncertainty analysis into the evaluation. The remainder of the studies evaluated direct medical interventions, eight of which were focused on specific implementation components (e.g., video observed therapy) which shared similar methodological challenges as the non-medical interventions. The majority of remaining evaluated medical interventions were focused on comparing various screening programs (e.g., immigrant screening program) and treatment regimens.

CONCLUSIONS

This scoping review identified a gap in literature in the evaluation of non-medical TB interventions. However, the identified articles provided useful examples of how economic modeling can be used to explore non-traditional interventions using existing economic evaluation methods.

Economic and modeling evidence for tuberculosis preventive therapy among people living with HIV: A systematic review and meta-analysis

BACKGROUND

Human immunodeficiency virus (HIV) is the strongest known risk factor for tuberculosis (TB) through its impairment of T-cell immunity. Tuberculosis preventive treatment (TPT) is recommended for people living with HIV (PLHIV) by the World Health Organization, as it significantly reduces the risk of developing TB disease. We conducted a systematic review and meta-analysis of modeling studies to summarize projected costs, risks, benefits, and impacts of TPT use among PLHIV on TB-related outcomes.

METHODS AND FINDINGS

We searched MEDLINE, Embase, and Web of Science from inception until December 31, 2020. Two reviewers independently screened titles, abstracts, and full texts; extracted data; and assessed quality. Extracted data were summarized using descriptive analysis. We performed quantile regression and random effects meta-analysis to describe trends in cost, effectiveness, and cost-effectiveness outcomes across studies and identified key determinants of these outcomes. Our search identified 6,615 titles; 61 full texts were included in the final review. Of the 61 included studies, 31 reported both cost and effectiveness outcomes. A total of 41 were set in low- and middle-income countries (LMICs), while 12 were set in high-income countries (HICs); 2 were set in both. Most studies considered isoniazid (INH)-based regimens 6 to 2 months long (n = 45), or longer than 12 months (n = 11). Model parameters and assumptions varied widely between studies. Despite this, all studies found that providing TPT to PLHIV was predicted to be effective at averting TB disease. No TPT regimen was substantially more effective at averting TB disease than any other. The cost of providing TPT and subsequent downstream costs (e.g. post-TPT health systems costs) were estimated to be less than $1,500 (2020 USD) per person in 85% of studies that reported cost outcomes (n = 36), regardless of study setting. All cost-effectiveness analyses concluded that providing TPT to PLHIV was potentially cost-effective compared to not providing TPT. In quantitative analyses, country income classification, consideration of antiretroviral therapy (ART) use, and TPT regimen use significantly impacted cost-effectiveness. Studies evaluating TPT in HICs suggested that TPT may be more effective at preventing TB disease than studies evaluating TPT in LMICs; pooled incremental net monetary benefit, given a willingness-to-pay threshold of country-level per capita gross domestic product (GDP), was $271 in LMICs (95% confidence interval [CI] -$81 to $622, p = 0.12) and was $2,568 in HICs (-$32,115 to $37,251, p = 0.52). Similarly, TPT appeared to be more effective at averting TB disease in HICs; pooled percent reduction in active TB incidence was 20% (13% to 27%, p < 0.001) in LMICs and 37% (-34% to 100%, p = 0.13) in HICs. Key limitations of this review included the heterogeneity of input parameters and assumptions from included studies, which limited pooling of effect estimates, inconsistent reporting of model parameters, which limited sample sizes of quantitative analyses, and database bias toward English publications.

CONCLUSIONS

The body of literature related to modeling TPT among PLHIV is large and heterogeneous, making comparisons across studies difficult. Despite this variability, all studies in all settings concluded that providing TPT to PLHIV is potentially effective and cost-effective for preventing TB disease.

Using Directly Observed Therapy (DOT) for latent tuberculosis treatment - A hit or a miss? A propensity score analysis of treatment completion among 274 homeless adults in Fulton County, GA

Latent tuberculosis infection (LTBI) treatment in persons at increased risk of disease progression is a key strategy with the strong potential to increase rate of tuberculosis (TB) decline in the United States. However, LTBI treatment in homeless persons, a population at high-risk of active TB disease, is usually associated with poor adherence. We describe the impact of using directly observed treatment (DOT) versus self-administered treatments (SAT) as an adherence-improving intervention to administer four months of daily rifampin regimen for LTBI treatment among homeless adults in Atlanta. Retrospective analysis of clinical care data on 274 homeless persons who initiated daily rifampin treatment for LTBI treatment at a county health department between January 2014 and December 2016 was performed. To reduce bias from non-random assignment of treatment, an inverse probability of treatment weighted (IPTW) logistic regression model was used to assess the effect of treatment type on treatment completion. Subgroup analyses were performed to assess heterogeneity of treatment effect on LTBI completion. Of 274 LTBI treatment initiators, 177 (65%) completed treatment [DOT 118/181 (65%), SAT 59/93 (63%)]. In the fully adjusted and weighted analysis, the odds of completing LTBI treatment on DOT was 40% higher than the odds of completing treatment by SAT [adjusted odds ratio (95% CI), aOR: 1.40 (1.07, 1.82), p = 0.014]. The unstable nature of homeless persons' lifestyle makes LTBI treatment difficult for many reasons. Our study lends support to the use of DOT to improve LTBI treatment completion among subgroups of homeless persons on treatment with daily rifampin.

Differences in time to injection onset by drug in California: Implications for the emerging heroin epidemic

BACKGROUND

Heroin use is increasing in the US. Heroin use may predispose users towards injection routes of drug administration as compared to other illicit substances.

OBJECTIVE

To explore the relationship between heroin use and drug injection, we compared time from first use to first injection (referred to as time to injection onset by drug [TTIOD]) of heroin, methamphetamine/speed, cocaine, and crack cocaine among people who inject drugs (PWID).

METHODS

Age of first use and first injection by drug was collected from 776 PWID. Survival analyses were used to determine TTIOD and to examine demographic factors associated with TTIOD. Cox regression analysis was used to determine demographic factors associated with drug-specific injection onset.

RESULTS

The eventual injection onset rate by the drug was 99% for participants who used heroin, 85% for participants who used methamphetamine/speed, 80% for participants who used powder cocaine, and 38% for participants who used crack cocaine. Hazard ratios for injection use within one year of first use by drug were: 1.37 (median survival time [MST] = 0.61 years) for heroin, 0.66 (MST = 1.10 years) for methamphetamine/speed, 0.50 (MST = 2.93 years) for powder cocaine, and 0.12 (MST = 39.59 years) for crack cocaine. Demographic differences in TTIOD were found for each drug. Demographic differences were found for eventual injection by drug for all substances except heroin.

CONCLUSION

Among PWID, heroin use was associated with a more rapid transition to injection and a higher rate of eventual heroin injection regardless of demographics. More robust, innovative efforts to reduce heroin use and prevent injection initiation are urgently needed.

Effectiveness of interventions for diagnosis and treatment of tuberculosis in hard-to-reach populations in countries of low and medium tuberculosis incidence: a systematic review

Tuberculosis is over-represented in hard-to-reach (underserved) populations in high-income countries of low tuberculosis incidence. The mainstay of tuberculosis care is early detection of active tuberculosis (case finding), contact tracing, and treatment completion. We did a systematic review with a scoping component of relevant studies published between 1990 and 2015 to update and extend previous National Institute for Health and Care Excellence (NICE) reviews on the effectiveness of interventions for identifying and managing tuberculosis in hard-to-reach populations. The analyses showed that tuberculosis screening by (mobile) chest radiography improved screening coverage and tuberculosis identification, reduced diagnostic delay, and was cost-effective among several hard-to-reach populations. Sputum culture for pre-migration screening and active referral to a tuberculosis clinic improved identification. Furthermore, monetary incentives improved tuberculosis identification and management among drug users and homeless people. Enhanced case management, good cooperation between services, and directly observed therapy improved treatment outcome and compliance. Strong conclusions cannot be drawn because of the heterogeneity of evidence with regard to study population, methodology, and quality.

Tackling TB in low-incidence countries: improving diagnosis and management in vulnerable populations

In low tuberculosis incidence regions, tuberculosis is mainly concentrated among hard-to-reach populations like migrants, homeless people, drug or alcohol abusers, prisoners and people living with HIV. To be able to eliminate tuberculosis from these low incidence regions tuberculosis screening and treatment programs should focus on these hard-to-reach populations. Here we discuss the barriers and facilitators of health care-seeking, interventions improving tuberculosis screening uptake and interventions improving treatment adherence in these hard-to-reach populations.

Tuberculosis screening in a novel substance abuse treatment center in Malaysia: implications for a comprehensive approach for integrated care

People who use drugs (PWUD) represent a key high risk group for tuberculosis (TB). The prevalence of both latent TB infection (LTBI) and active disease in drug treatment centers in Malaysia is unknown. A cross-sectional convenience survey was conducted to assess the prevalence and correlates of LTBI among attendees at a recently created voluntary drug treatment center using a standardized questionnaire and tuberculin skin testing (TST). Participants (N=196) were mostly men (95%), under 40 (median age=36 years) and reported heroin use immediately before treatment entry (75%). Positive TST prevalence was 86.7%. Nine (4.6%) participants were HIV-infected. Previous arrest/incarcerations (AOR=1.1 for every entry, p<0.05) and not being HIV-infected (AOR=6.04, p=0.03) were significantly associated with TST positivity. There is an urgent need to establish TB screening and treatment programs in substance abuse treatment centers and to tailor service delivery to the complex treatment needs of patients with multiple medical and psychiatric co-morbidities.

Delayed diagnosis and associated factors among new pulmonary tuberculosis patients diagnosed at the emergency department of a tertiary care hospital in Porto Alegre, South Brazil: a prospective patient recruitment study

Background

Control of tuberculosis (TB) depends on early diagnosis and treatment at the primary health care level. However, many patients are still diagnosed late with TB at hospitals. The present study aimed to investigate the delay in diagnosis of TB patients at the emergency department.

Methods

This was a prospective study in a general, tertiary care, university-affiliated hospital of a city with a high prevalence of TB in Brazil. New TB patients ≥ 14 years diagnosed with pulmonary TB at the emergency department of Hospital de Clínicas de Porto Alegre were prospectively recruited between February 2010 and January 2012. The consenting patients meeting our inclusion criteria were interviewed using a pre-tested questionnaire. We evaluated the delay in time until diagnosis and identified factors associated with delayed diagnosis (patient and health care system delays).

Results

We included 153 patients. The median total time of delay, patient delay, and health care system delay were 60 (interquartile range [IQR]: 30–90.5 days), 30 (lQR: 7–60 days), and 18 (IQR: 9–39.5 days) days, respectively. The factors that were independently associated with patient delay (time ≥ 30 days) were crack (odds ratio [OR] = 4.88, p = 0.043) and cocaine (OR = 6.68, p = 0.011) use. The factors that were independently associated with health care system delay (time ≥ 18 days) were weight loss (OR = 2.76, p = 0.025), miliary pattern (OR = 5.33, p = 0.032), and fibrotic changes (OR = 0.12, p = 0.013) on chest X-ray.

Conclusions

Patient delay appears to be the main problem in this city with a high prevalence of TB in Brazil. The main factor associated with patient delay is drug abuse (crack and cocaine). Our study shows substance abuse programs need to be aware of control of TB, with health interventions focusing on TB education programs.

Tuberculosis, injecting drug use and integrated HIV-TB care: a review of the literature

BACKGROUND

People who inject drugs (PWID) are at increased risk of tuberculosis (TB) and reduced retention in treatment. There is a need to document strategies for integrated delivery of HIV, TB and drug dependency care.

METHODS

This article reviews the literature on rates of TB mono- and co-infection, and published and grey literature descriptions of TB and HIV-TB care, among PWID.

RESULTS

Latent TB infection prevalence was high and active disease more common among HIV-positive PWID. Data on multidrug-resistant TB and co-infections among PWID were scarce. Models of TB care fell into six categories: screening and prevention within HIV-risk studies; prevention at TB clinics; screening and prevention within needle-and-syringe-exchange (NSP) and drug treatment programmes; pharmacy-based TB treatment; TB service-led care with harm reduction/drug treatment programmes; and TB treatment within drug treatment programmes. Co-location with NSP and opioid substitution therapy (OST), combined with incentives, consistently improved screening and prevention uptake. Small-scale combined TB treatment and OST achieved good adherence in diverse settings. Successful interventions involved collaboration across services; a client-centred approach; and provision of social care. No peer-reviewed studies described models of integrated HIV-TB care for PWID but grey literature highlighted key components: co-located services, provision of drug treatment, multidisciplinary staff training; and remaining barriers: staffing inefficiencies, inadequate funding, police interference, and limited OST availability.

CONCLUSIONS

Integration with drug treatment improves PWID engagement in TB services but there is a need to document approaches to HIV-TB care, improve surveillance of TB and co-infections among PWID, and advocate for improved OST availability.

Costs and cost-effectiveness of four treatment regimens for latent tuberculosis infection

RATIONALE

Isoniazid given daily for 9 months is the standard treatment for latent tuberculosis infection (LTBI), but its effectiveness is limited by poor completion rates. Shorter course regimens and regimens using directly observed therapy result in improved adherence but have higher upfront costs.

OBJECTIVES

To evaluate the costs and cost-effectiveness of regimens for the treatment of LTBI.

METHODS

We used a computerized Markov model to estimate total societal costs and benefits associated with four regimens for the treatment of LTBI: self-administered isoniazid daily for 9 months, directly observed isoniazid twice-weekly for 9 months, directly observed isoniazid plus rifapentine once weekly for 3 months, and self-administered rifampin daily for 4 months. In the base-case analysis, subjects were assumed to have newly positive tuberculin skin tests after recent exposure to infectious tuberculosis.

MEASUREMENTS AND MAIN RESULTS

We determined the costs of treatment, quality-adjusted life-years gained, and cases of active tuberculosis prevented. In the base-case analysis, rifampin dominated (less costly with increased benefits) all other regimens except isoniazid plus rifapentine, which was more effective at a cost $48,997 per quality-adjusted life year gained. Isoniazid plus rifapentine dominated all regimens at a relative risk of disease 5.2 times the baseline estimate, or with completion rates less than 34% for isoniazid or 37% for rifampin. Rifampin could be 17% less efficacious than self-administered isoniazid and still be cost-saving compared with this regimen.

CONCLUSIONS

In our model, rifampin is cost-saving compared with the standard therapy of self-administered isoniazid. Isoniazid plus rifapentine is cost-saving for extremely high-risk patients and is cost-effective for lower-risk patients.

Tuberculosis and illicit drug use: review and update

Illicit drug users continue to be a group at high risk for tuberculosis (TB). Here, we present an updated review of the relationship between TB and illicit drug use, and we summarize more than a decade of new research. Drug users, and injection drug users in particular, have driven TB epidemics in a number of countries. The successful identification and treatment of TB among illicit drug users remain important components of a comprehensive TB strategy, but illicit drug users present a unique set of challenges for TB diagnosis and control. New diagnostic modalities, including interferon-gamma-release assays, offer potential for improved diagnosis and surveillance among this group, along with proven treatment strategies that incorporate the use of directly observed therapy with treatment for drug abuse. Special considerations, including coinfection with viral hepatitis and the rifampin-methadone drug interaction, warrant clinical attention and are also updated here.

Theorizing "Big Events" as a potential risk environment for drug use, drug-related harm and HIV epidemic outbreaks

Political-economic transitions in the Soviet Union, Indonesia, and China, but not the Philippines, were followed by HIV epidemics among drug users. Wars also may sometimes increase HIV risk. Based on similarities in some of the causal pathways through which wars and transitions can affect HIV risk, we use the term "Big Events" to include both. We first critique several prior epidemiological models of Big Events as inadequately incorporating social agency and as somewhat imprecise and over-generalizing in their sociology. We then suggest a model using the following concepts: first, event-specific HIV transmission probabilities are functions of (a) the probability that partners are infection-discordant; (b) the infection-susceptibility of the uninfected partner; (c) the infectivity of the infected--as well as (d) the behaviours engaged in. These probabilities depend on the distributions of HIV and other variables in populations. Sexual or injection events incorporate risk behaviours and are embedded in sexual and injection partnership patterns and community networks, which in turn are shaped by the content of normative regulation in communities. Wars and transitions can change socio-economic variables that can sometimes precipitate increases in the numbers of people who engage in high-risk drug and sexual networks and behaviours and in the riskiness of what they do. These variables that Big Events affect may include population displacement; economic difficulties and policies; police corruption, repressiveness, and failure to preserve order; health services; migration; social movements; gender roles; and inter-communal violence--which, in turn, affect normative regulation, youth alienation, networks and behaviours. As part of these pathways, autonomous action by neighbourhood residents, teenagers, drug users and sex workers to maintain their economic welfare, health or happiness may affect many of these variables or otherwise mediate whether HIV epidemics follow transitions. We thus posit that research on whether and how these interacting causal pathways and autonomous actions are followed by drug-related harm and/or HIV or other epidemics can help us understand how to intervene to prevent or mitigate such harms.

Health state utilities in latent and active tuberculosis

BACKGROUND

Tuberculosis (TB) remains a major public health threat worldwide. Numerous cost-effectiveness analyses of TB screening and treatment strategies have been recently published, but none have utilized quality-adjusted life-years as recommended because of the lack of utilities for TB health states.

OBJECTIVE

To characterize and compare utility scores from either active TB or latent TB infection (LTBI) participants.

METHODS

Consenting patients attending a population-based screening and treatment clinic were administered the Short Form 36 (SF-36), the Health Utilities Index 2/3 (HUI2/3), and a general health visual analog scale (VAS) along with demographic questions. SF-36 scores were converted to Short Form 6D (SF-6D) utility scores using an accepted algorithm. Utility results were compared across scales, and construct validity was assessed.

RESULTS

A total of 162 TB patients (78 LTBI and 84 active TB) with available SF-36 and all four utility scores (Health Utilities Index 2, Health Utilities Index 3, SF-6D and VAS) were included in the analysis. Those with active TB had significantly lower SF-36 and utility scores than those with LTBI. Although all appeared to exhibit construct validity, the HUI2/3 and the VAS appeared to have significant ceiling effects, whereas the SF-6D had significant floor effects.

CONCLUSIONS

Health state utility values for active TB and LTBI have been determined using different instruments. The three measures did not generate identical utility scores. The HUI2/3 was limited by ceiling effects, whereas the SF-6D appeared to display floor effects.

Cost-effectiveness of LTBI treatment for TB contacts in British Columbia

BACKGROUND

Contacts of patients with active tuberculosis ("TB contacts") with a tuberculin skin test (TST) size > or = 5 mm are currently recommended treatment for latent TB infection (LTBI). Knowing the cost-effectiveness of LTBI therapy for specific TB contact subpopulations may improve the use of limited resources by reducing the treatment of persons at low TB risk.

OBJECTIVE

To evaluate the cost-effectiveness of LTBI therapy for different TB contact populations defined by important risk factors, and to propose an optimal policy based on different recommendation for each subgroup of contacts.

METHODS

A 6-year Markov decision analytic model simulating the quality-adjusted life years (QALYs), number of active TB cases prevented, and costs for hypothetical cohorts of Canadian TB contacts defined by TST size, age group (< 10 y/o or above), ethnicity, closeness of contact, and Bacillus Calmette-Guérin (BCG) vaccination status.

RESULTS

For the majority of subgroups, the current policy of preventive therapy in those with positive TST was the most cost-effective. Nevertheless, our analysis determined that LTBI treatment is not cost-effective in nonhousehold Canadian-born (nonaboriginal) or foreign-born contacts age > or = 10 y/o. On the other hand, empirical treatment without screening of all non-BCG-vaccinated household contacts age < 10 y/o appeared cost-effective. Such an optimal approach would result in an incremental net monetary benefit of $25 for each contact investigated for a willingness-to-pay of $50,000/QALY. Results were robust to several alternative assumptions considered in sensitivity analyses.

CONCLUSIONS

The current practice of LTBI treatment for TB contacts with a TST size > or = 5 mm is cost-effective. A customized approach based on excluding low risk groups from screening and providing treatment to high risk contacts without screening could improve the performance of the program.

Hospital- versus community-based syringe exchange: a randomized controlled trial

This study examined the effect of syringe exchange program setting on the injection practices, health status, and health service utilization patterns of injection drug users (IDUs) recruited from a public urban hospital. One hundred sixty-six participants were randomized to either community- or hospital-based syringe exchange services. Poisson regression models were used to compare service utilization between groups. In both conditions, risky drug use practices decreased, and physical health functioning improved over time. Hospital-based syringe exchange program (SEP) attendees had 83% more inpatient admissions (p < .0001) and 22% more ambulatory care visits (p < .0001) than those assigned to the community-based SEP condition. Syringe exchange services that are integrated into public hospital settings may serve as a valuable strategy to engage hard to reach IDU populations in behavioral interventions designed to reduce HIV risk transmission behaviors and increase access to, or engagement in, the use of secondary and tertiary preventive medical care.

Cost-effectiveness of tuberculosis evaluation and treatment of newly-arrived immigrants

BACKGROUND

Immigrants to the U.S. are required to undergo overseas screening for tuberculosis (TB), but the value of evaluation and treatment following entry to the U.S. is not well understood. We determined the cost-effectiveness of domestic follow-up of immigrants identified as tuberculosis suspects through overseas screening.

METHODS

Using a stochastic simulation for tuberculosis reactivation, transmission, and follow-up for a hypothetical cohort of 1000 individuals, we calculated the incremental cost-effectiveness of follow-up and evaluation interventions. We utilized published literature, California Reports of Verified Cases of Tuberculosis (RVCTs), demographic estimates from the California Department of Finance, Medicare reimbursement, and Medi-Cal reimbursement rates. Our target population was legal immigrants to the United States, our time horizon is twenty years, and our perspective was that of all domestic health-care payers. We examined the intervention to offer latent tuberculosis therapy to infected individuals, to increase the yield of domestic evaluation, and to increase the starting and completion rates of LTBI therapy with INH (isoniazid). Our outcome measures were the number of cases averted, the number of deaths averted, the incremental dollar cost (year 2004), and the number of quality-adjusted life-years saved.

RESULTS

Domestic follow-up of B-notification patients, including LTBI treatment for latently infected individuals, is highly cost-effective, and at times, cost-saving. B-notification follow-up in California would reduce the number of new tuberculosis cases by about 6-26 per year (out of a total of approximately 3000). Sensitivity analysis revealed that domestic follow-up remains cost-effective when the hepatitis rates due to INH therapy are over fifteen times our best estimates, when at least 0.4 percent of patients have active disease and when hospitalization of cases detected through domestic follow-up is no less likely than hospitalization of passively detected cases.

CONCLUSION

While the current immigration screening program is unlikely to result in a large change in case rates, domestic follow-up of B-notification patients, including LTBI treatment, is highly cost-effective. If as many as three percent of screened individuals have active TB, and early detection reduces the rate of hospitalization, net savings may be expected.

Efficient allocation of resources to prevent HIV infection among injection drug users: the Prevention Point Philadelphia (PPP) needle exchange program

The objective of this study is to determine the allocation of resources within a multi-site needle exchange program (NEP) that achieves the largest possible reduction in new HIV infections at minimum cost. We present a model that relates the number of injection drug user (IDU) clients and the number of syringes exchanged per client to both the costs of the NEP and the expected reduction in HIV infections per unit time. We show that cost-effective allocation within a multi-site NEP requires that sites be located where the density of IDUs is highest, and that the number of syringes exchanged per client be equal across sites. We apply these optimal allocation rules to a specific multi-site needle exchange program, Prevention Point Philadelphia (PPP). This NEP, we find, needs to add 2 or 3 new sites in neighborhoods with the highest density of IDU AIDS cases, and to increase its total IDU client base by about 28%, from approximately 6400 to 8200 IDU clients. The case-study NEP also needs to increase its hours of operation at two existing sites, where the number of needles distributed per client is currently sub-optimal, by 50%. At the optimal allocation, the estimated cost per case of HIV averted would be dollar 2800 (range dollar 2300-dollar 4200). Such a favorable cost-effectiveness ratio derives primarily from PPP's low marginal costs per distributed needle.

Unmet need for recommended preventive health services among clients of California syringe exchange programs: implications for quality improvement

BACKGROUND

Comprehensive preventive services are recommended for injection drug users (IDU), including screening tests, vaccinations, risk reduction counseling, and sterile syringes. Syringe exchange programs (SEP) may facilitate receipt of preventive services by IDUs, but whether SEP clients receive recommended preventive care is not known. We examined use of recommended preventive services by clients of 23 SEPs throughout California.

METHODS

Five hundred and sixty SEP clients were recruited from 23 SEPs throughout California between March and September 2003. Receipt of 10 recommended preventive services and source of care (SEP versus non-SEP providers) was ascertained from client interviews.

RESULTS

On average, SEP clients received only 13% of recommended preventive services and 49% of clients received none of the recommended services. Of services that were received, 76% were received from SEPs. In multivariate analysis, use of drug treatment and more frequent SEP visits were associated with receipt of recommended preventive services by clients.

CONCLUSIONS

SEPs are often the only source of preventive care for their IDU clients. Still, SEP clients fail to receive most recommended preventive services. Interventions to increase use of preventive services and improve the quality of preventive care received by IDUs, such as increased access to drug treatment and SEPs, are needed.

Evaluation of Needle Exchange Programs

Needle exchange programs exist in every major population area in the United States and in many other countries. Some operate legally under emergency health decrees issued by local departments of health, with the stated intention of risk reduction through the removal of used injection equipment from use by injection drug users. It is theorized that this results in a reduced transmission of human immunodeficiency virus, hepatitis, and, possibly, other blood-borne diseases. Needle exchange programs also offer access to drug treatment programs for the participants. It is a difficult but necessary task to evaluate these programs. This article examines examples of evaluations attempted in the past and discusses the challenges of such evaluations. Experimental evaluations, economic program analysis, legal aspects, and risk-benefit assessment along with ethical aspects are considered. An outline of program evaluation is proposed. Needle exchange programs offer an opportunity to encourage risk reduction and to offer counseling and access to health care for individuals at high risk. It is essential that such programs demonstrate their effectiveness. Assumptions of efficacy are insufficient for health care in the twenty-first century.

Impact of monetary incentives on adherence to referral for screening chest x-rays after syringe exchange-based tuberculin skin testing

INTRODUCTION

Syringe-exchange programs (SEPs) have proven to be valuable sites to conduct tuberculin skin testing among active injection drug users. Chest x-rays (CXRs) are needed to exclude active tuberculosis prior to initiating treatment for latent tuberculosis infection. Adherence of drug users to referral for off-site chest x-rays has been incomplete. Previous cost modeling demonstrated that a monetary incentive to promote adherence could be justified on the cost basis if it had even a modest effect on adherence.

METHODS

We compared adherence to referral for chest x-rays among injection drug users undergoing syringe exchange-based tuberculosis screening in New York City before and after the implementation of monetary incentives.

RESULTS

From 1995 to 1998, there were 119 IDUs referred for CXRs based on tuberculin skin testing at the SEP. From 1999 to 2001, there were 58 IDUs referred for CXRs with a $25 incentive based on adherence. Adherence to CXR referral within 7 days was 46/58 (79%) among individuals who received the monetary incentive versus 17/119 (14%) prior to the implementation of the monetary incentive (P<.0001; odds ratio [OR]=23; 95% confidence interval [CI]=9.5-57). The median time to obtaining a CXR was significantly shorter among those given the incentive than among those referred without the incentive (2 vs. 11 days, P<.0001). In multivariate logistic regression analysis, use of the incentive was highly independently associated with increased adherence (OR=22.9; 95% CI=10-52).

CONCLUSIONS

Monetary incentives are highly effective in increasing adherence to referral for screening CXRs to exclude active tuberculosis after syringe exchange-based tuberculin skin testing. Prior cost modeling demonstrated that monetary incentives could be justified on the cost basis if they had even a modest effect on adherence. The current data demonstrated that monetary incentives are highly effective at increasing adherence in this setting and therefore are justifiable on a cost basis. When health care interventions for drug users require referral off site, monetary incentives may be particularly valuable in promoting adherence.

Costs and effectiveness--the impact of economic studies on TB control

This paper assesses the impact of economic studies on TB control during the period 1982-2002, with a focus on cost and cost-effectiveness studies. It begins by identifying broad categories of economic study relevant to TB control, and how economic studies can, theoretically, have an impact on TB control. The impact that economic studies of TB control have had in practice is then analysed through a systematic review of the literature on cost and cost-effectiveness studies related to TB control, and three case studies (one cost study and two cost-effectiveness studies). The results show that in the past 20 years, 66 cost-effectiveness studies and 31 cost studies have been done on a variety of important TB control topics, with a marked increase occurring after 1994. In terms of numbers, these studies have had most potential for impact in industrialized countries, and within industrialized countries are most likely to have had an impact on policy and practice related to screening and preventive therapy. In developing countries with a high burden of tuberculosis, far fewer studies have been undertaken. Here, the main impact of economic studies has been influencing policy and practice on the use of short-course chemotherapy, justifying the implementation of community-based care in Africa, and helping to mobilize funding for TB control based on the argument that short-course treatment for TB is one of the most cost-effective health interventions available. For the future, cost and cost-effectiveness studies will continue to be relevant, as will other types of economic study.