Methadone maintenance and other factors associated with intraindividual temporal trends in injection-drug use

Interventions to prevent HIV and Hepatitis C in people who inject drugs: a review of reviews to assess evidence of effectiveness

BACKGROUND

Injecting drug use is a major risk factor for the acquisition and transmission of HIV and Hepatitis C virus (HCV). Prevention of these infections among people who inject drugs (PWID) is critical to reduce ongoing transmission, morbidity and mortality.

METHODS

A review of reviews was undertaken involving systematic literature searches of Medline, Embase, CINAHL, PsychINFO, IBSS and the Cochrane Library (2000-2011) to identify English language reviews regarding the effectiveness of harm reduction interventions in relation to HIV transmission, HCV transmission and injecting risk behaviour (IRB). Interventions included needle and syringe programmes (NSP); the provision of injection paraphernalia; opiate substitution treatment (OST); information, education and counselling (IEC); and supervised injecting facilities (SIFs). Reviews were classified into 'core' or 'supplementary' using critical appraisal criteria, and the strength of review-level evidence was assessed.

RESULTS

Twelve core and thirteen supplementary reviews were included. From these reviews we identified: (i) for NSP: tentative review-level evidence to support effectiveness in reducing HIV transmission, insufficient review-level evidence relating to HCV transmission, but sufficient review-level evidence in relation to IRB; (ii) for OST: sufficient review-level evidence of effectiveness in relation to HIV transmission and IRB, but tentative review-level evidence in relation to HCV transmission; (iii) for IEC, the provision of injection paraphernalia and SIFs: tentative review-level evidence of effectiveness in reducing IRB; and either insufficient or no review-level evidence for these interventions in relation to HIV or HCV transmission.

CONCLUSION

Review-level evidence indicates that harm reduction interventions can reduce IRB, with evidence strongest for OST and NSP. However, there is comparatively little review-level evidence regarding the effectiveness of these interventions in preventing HCV transmission among PWID. Further studies are needed to assess the effectiveness and impact of scaling up comprehensive packages of harm reduction interventions to minimise HIV and HCV transmission among PWID.

Oral substitution treatment of injecting opioid users for prevention of HIV infection

BACKGROUND

Injecting drug users are vulnerable to infection with Human Immunodeficiency Virus (HIV) and other blood borne viruses as a result of collective use of injecting equipment as well as sexual behaviour

OBJECTIVES

To assess the effect of oral substitution treatment for opioid dependent injecting drug users on risk behaviours and rates of HIV infections

SEARCH STRATEGY

We searched the Cochrane Central Register of Controlled Trials, MEDLINE, EMBASE and PsycINFO to May 2011. We also searched reference lists of articles, reviews and conference abstracts

SELECTION CRITERIA

Studies were required to consider the incidence of risk behaviours, or the incidence of HIV infection related to substitution treatment of opioid dependence. All types of original studies were considered. Two authors independently assessed each study for inclusion

DATA COLLECTION AND ANALYSIS

Two authors independently extracted key information from each of the included studies. Any differences were resolved by discussion or by referral to a third author.

MAIN RESULTS

Thirty-eight studies, involving some 12,400 participants, were included. The majority were descriptive studies, or randomisation processes did not relate to the data extracted, and most studies were judged to be at high risk of bias. Studies consistently show that oral substitution treatment for opioid-dependent injecting drug users with methadone or buprenorphine is associated with statistically significant reductions in illicit opioid use, injecting use and sharing of injecting equipment. It is also associated with reductions in the proportion of injecting drug users reporting multiple sex partners or exchanges of sex for drugs or money, but has little effect on condom use. It appears that the reductions in risk behaviours related to drug use do translate into reductions in cases of HIV infection. However, because of the high risk of bias and variability in several aspects of the studies, combined totals were not calculated.

AUTHORS' CONCLUSIONS

Oral substitution treatment for injecting opioid users reduces drug-related behaviours with a high risk of HIV transmission, but has less effect on sex-related risk behaviours. The lack of data from randomised controlled studies limits the strength of the evidence presented in this review.

Substitution treatment of injecting opioid users for prevention of HIV infection

BACKGROUND

Injecting drug users are vulnerable to infection with HIV and other blood borne viruses as a result of collective use of injecting equipment as well as sexual behaviour.

OBJECTIVES

To assess the effect of oral substitution treatment for opioid dependent injecting drug users on rates of HIV infections, and high risk behaviours.

SEARCH STRATEGY

We searched the Cochrane Central Register of Controlled Trials, MEDLINE, EMBASE and PsycINFO to March 2007. We also searched reference lists of articles, reviews and conference abstracts

SELECTION CRITERIA

Studies were required to consider the incidence of risk behaviours, or the incidence of HIV infection related to substitution treatment of opioid dependence. All types of original studies were considered. Two reviewers independently assessed studies for inclusion.

DATA COLLECTION AND ANALYSIS

One reviewer extracted data from included studies, assessed quality and confirmed decisions by consulting with all other reviewers.

MAIN RESULTS

Thirty-three studies, involving 10,400 participants, were included. The majority were not randomised controlled studies and there were problems of confounding and bias. The studies varied in several aspects limiting the extent of quantitative analysis. Studies consistently show that oral substitution treatment for opioid-dependent injecting drug users is associated with statistically significant reductions in illicit opioid use, injecting use and sharing of injecting equipment. It is also associated with reductions in the proportion of injecting drug users reporting multiple sex partners or exchanges of sex for drugs or money, but has little effect on condom use. It appears that the reductions in risk behaviours related to drug use do translate into reductions in cases of HIV infection.

AUTHORS' CONCLUSIONS

Oral substitution treatment for injecting opioid users reduces drug-related behaviours with a high risk of HIV transmission, but has less effect on sex-related risk behaviours. The lack of data from randomised controlled studies limits the strength of the evidence presented in this review.

Substitution treatment of injecting opioid users for prevention of HIV infection

BACKGROUND

Injecting drug users are vulnerable to infection with HIV and other blood borne viruses as a result of collective use of injecting equipment as well as sexual behaviour.

OBJECTIVES

To assess the effect of oral substitution treatment for opioid dependent injecting drug users on rates of HIV infections, and high risk behaviours.

SEARCH STRATEGY

Multiple electronic databases were searched. Reference lists of retrieved studies, reviews and conference abstracts were handsearched.

SELECTION CRITERIA

Studies were required to consider the incidence of risk behaviours, or the incidence of HIV infection related to substitution treatment of opioid dependence. All types of original studies were considered.

DATA COLLECTION AND ANALYSIS

Each potentially relevant study was independently assessed by two reviewers. For studies that met the inclusion criteria, key information was extracted by one reviewer and confirmed by consultation between all four reviewers.

MAIN RESULTS

Twenty-eight studies, involving 7900 participants, were included. The majority were not randomised controlled studies. Issues of confounding and bias are discussed. The studies varied in several aspects limiting the extent of quantitative analysis.

REVIEWERS' CONCLUSIONS

Oral substitution treatment for opioid-dependent injecting drug users is associated with statistically significant reductions in illicit opioid use, injecting use and sharing of injecting equipment. It is also associated with reductions in the proportion of injecting drug users reporting multiple sex partners or exchanges of sex for drugs or money, but has little effect on condom use. It appears that the reductions in risk behaviours related to drug use do translate into reductions in cases of HIV infection. The lack of data from randomised controlled studies limits the strength of the evidence presented in this review. However, these findings add to the stronger evidence of effectiveness of substitution treatment on drug use, and treatment retention outcomes shown by other systematic reviews. On this basis, the provision of substitution treatment for opioid dependence in countries with emerging HIV and injecting drug use problems as well as in countries with established populations of injecting drug users should be supported.

Lack of increased HIV risk behavior among injection drug users participating in the AIDSVAX B/E HIV vaccine trial in Bangkok, Thailand

OBJECTIVE

To determine whether HIV vaccine trial participation leads to increased risk behavior through beliefs about vaccine protection against infection.

METHODS

Changes in risk behavior were evaluated among 2545 injection drug users participating in the AIDSVAX B/E vaccine trial in Bangkok, enrolled from March 1999 to August 2000. Demographic characteristics, beliefs and risk behavior were assessed at baseline and every 6 months thereafter. Risk-reduction counseling was provided at every study visit. Generalized estimation-equation logistic regression analysis was used to study trends in risk behavior and associated factors.

RESULTS

Participants were 93.4% male, their median age was 26 years, and 67.2% had at least secondary education. At baseline, 61.3% were receiving methadone detoxification and 20.9% were receiving methadone maintenance. From baseline to the 12-month follow-up visit, injection drug use decreased from 93.8% to 66.5% (P < 0.001) and needle sharing from 33.0% to 17.5% (P < 0.001). Multivariate analyses showed earlier follow-up time (at baseline and 6 months) and believing the vaccine to be efficacious associated with more-frequent injecting; younger age and lower education associated with less-frequent injecting. Earlier follow-up time (at baseline), younger age, and injection of methamphetamine and midazolam were associated with more-frequent needle sharing; methadone treatment and injecting less than weekly were associated with less-frequent needle sharing.

CONCLUSIONS

Injection drug use and needle sharing decreased during the first 12 months of the trial. No increases in risk behavior in relation to beliefs about vaccine protection against HIV infection could be identified.

Recommendations for incorporating human immunodeficiency virus (HIV) prevention into the medical care of persons living with HIV

The estimated number of annual new human immunodeficiency virus (HIV) infections in the United States has remained at 40,000 for >10 years. Reducing the rate of transmission will require new strategies, including emphasis on prevention of transmission by HIV-infected persons. Medical care providers can affect HIV transmission by screening HIV-infected patients for risk behaviors, communicating prevention messages, discussing sexual and drug-use behaviors, reinforcing changes to safer behavior, referring patients for services such as substance abuse treatment, facilitating partner counseling and referral, and identifying and treating other sexually transmitted diseases. The Centers for Disease Control and Prevention (CDC), the Health Resources and Services Administration (HRSA), the National Institutes of Health (NIH), and the HIV Medicine Association (HIVMA) of the Infectious Diseases Society of America (IDSA) have recently collaborated to develop evidence-based recommendations for incorporating HIV prevention into the medical care of persons living with HIV. This article summarizes key aspects of the recommendations.

HIV risk reduction in a cohort of injecting drug users in Bangkok, Thailand

OBJECTIVE

To determine changes in risk behavior in relation to study participation among injecting drug users (IDUs) in Bangkok, Thailand.

METHODS

During 1995-1996, 1,209 HIV-seronegative IDUs were recruited from Bangkok Metropolitan Administration drug abuse treatment programs to participate in a prospective cohort study. Study visits occurred every 4 months, at which the participants underwent an interview to assess risk behavior and HIV counseling and testing. Eight hundred nine of the IDUs were considered "long-term" participants, who remained in the study through at least the first four scheduled follow-up visits (16 months). Injection risk behavior at each study visit was measured on a four-point scale strongly associated with incident HIV infections in the cohort. Individual regression slopes were used to assess changes in injection risk behavior (risk increase, no change, or risk reduction).

RESULTS

Of the 806 long-term study participants, 79% showed declines, 4% showed no change, and 17% showed increases in injection risk behavior. The percentage of participants in the highest-risk category (injecting daily or more frequently and sharing needles and syringes) declined from 42% at baseline to 3% at the final follow-up visit. Being in methadone maintenance treatment was associated with stable low rates of injection risk behavior, while recruitment from the 45-day detoxification treatment was associated with reductions in injection risk behavior. The risk reduction was independent of decline in risk behavior among IDUs in the community at large.

CONCLUSIONS

Participation in this cohort study was associated with substantial declines in injection risk behavior. This information is important in the evaluation of possible adverse behavioral effects of participation in future preventive HIV vaccine trials including IDUs, particularly in developing country settings.

Between-city variation in frequency of injection among Puerto Rican injection drug users: East Harlem, New York, and Bayamon, Puerto Rico

Frequency of injection has been consistently found to be higher among Puerto Rican Injection drug users (IDUs) than among other groups of IDUs. Several explanations have been suggested, but an empirical explanation has yet to be presented. This study compares the frequency of injection of Puerto Rican IDUs in East Harlem, New York, with that of IDUs in Bayamon, Puerto Rico. Study subjects comprised 521 Puerto Rican IDUs from East Harlem and 303 IDUs from Bayamon. The mean frequency of injection among IDUs in East Harlem was 2.8, the corresponding mean in Bayamon was 5.4. Younger IDUs reported a higher number of daily injection episodes than older IDUs, and the IDU group in Bayamon was 5 years younger than the group in East Harlem. The drug use variables accounted for a greater portion of the between-city difference than the demographic and psychosocial variables. Use of noninjected drugs, as well as the use of prescribed methadone, were found to be associated with a lower number of daily injections. Conversely, injection of cocaine, injection of cocaine mixed with heroin ("speedball"), and injection of larger amounts of drug solution were found to be associated with a higher number of daily injections.

Drug injection rates and needle-exchange use in New York City, 1991-1996

Objectives included (1) to develop methods for identifying injection drug users with accelerating injection habits so they might be referred to counseling and treatment and (2) to investigate behavioral correlates of accelerating injection habits, including syringe-exchange program utilization. Data on drug use, enrollment in methadone maintenance, and demographic variables were obtained from 328 subjects who were seronegative for human immunodeficiency virus (HIV) who attended anywhere from 4 to 11 quarterly study visits for interview, HIV pretest counseling and risk reduction counseling, and blood donation for HIV antibody testing. Subjects were recalled 2 weeks after each study visit to receive their results and post-test counseling. We characterized subjects according to their patterns of drug injection as accelerating, decelerating, or stable, using intraindividual regression analyses and categorization rules, and by syringe-exchange use as consistent users, sporadic users, or nonusers. The present subjects included 52% with decelerating, 29% with stable, and 19% with accelerating rates of drug injection. There were 128 subjects (39%) who were categorized as consistent users of syringe-exchange programs, 84 (25%) were categorized as sporadic users, and 116 (35%) were categorized as nonusers. All syringe-exchange groups showed significantly decelerating drug injection. Rates of decline were significantly less, however, among consistent syringe-exchange users than sporadic or nonusers of syringe exchanges. Categorical analysis also showed significant differences among groups, with 30% of consistent syringe-exchange program users having accelerating rates of drug injection compared to 9% of nonusers and 17% of sporadic users. That consistent syringe-exchange users included a larger proportion of individuals whose drug habits were accelerating than did sporadic users or nonusers of syringe exchanges suggests a need for improved identification and counseling of such subjects by syringe-exchange program staff. The present statistical approaches may be of value in targeting such efforts. The ability of a syringe-exchange program to attract a disproportionate share of drug users with accelerating rates of drug injection underscores the importance of these programs to HIV prevention efforts.

Homelessness and gender in out-of-treatment drug users

This study examines 5225 out-of-treatment crack users and drug injectors drawn from five different geographic areas to examine selected factors associated with homelessness. Of these crack users, 27% considered themselves undomiciled, and 60% had previously entered some type of drug treatment. Logistic regression found that substance abusers who were married, female, and persons of color were less likely to be without a home when other variables were controlled. Trading sex for money and perceived chance of getting acquired immunodeficiency syndrome (AIDS) were associated positively with homelessness, while participating in methadone detoxification and methadone maintenance programs seemed to offer some protection from homelessness.

Drug abuse treatment as an HIV prevention strategy: a review

We review drug abuse treatment as a means of preventing infection with HIV. Thirty-three studies, with an aggregate of over seventeen thousand subjects, were published in peer-reviewed journals from 1988-1998. Research on the utility of drug abuse treatment as an HIV prevention strategy has focused primarily on methadone maintenance treatment (MMT) rather than other modalities such as residential or outpatient drug-free treatment. Recent research provides clear evidence that MMT reduces HIV risk behaviors, particularly needle-use, and strong evidence that MMT prevents HIV infection. There is less definitive evidence that MMT reduces needle-sharing and unsafe sexual behavior, or that other treatment modalities prevent HIV infection. Future research should take into account patient self-selection processes and investigate other treatment modalities for heroin and stimulant abuse to determine their effects on HIV risk behaviors and HIV infection.

Engaging hospitalized heroin-dependent patients into substance abuse treatment

The purpose of this study was to evaluate a 6-month outpatient program developed to improve abstinence and other health and social problems of heroin-addicted persons hospitalized in an urban academic medical center's medical or surgical unit and referred from the Substance Abuse Consult Service. Treatment intervention consisted of methadone therapy, daily group therapy, individual case management, medical and psychiatric consultation, and social services. The first 67 patients referred were followed for 6 months. Outcome measures were retention in treatment, urine drug screens, and health and social indicators. Patients averaged 19 weeks in treatment, with 52% of patients completing the 6-month program. Urine toxicology screens showed a reduction of illicit drug use. Patients improved deficits in health and social indicators by obtaining medical coverage, keeping outpatient medical appointments, and improving their housing conditions. Findings suggest that this combination of intensive psychosocial treatment with opioid substitution following an acute illness substantially impacts treatment outcomes. Implications for service delivery and health-care economics are discussed.

Previous participation in outpatient methadone program and residential treatment outcome: a research note from Hong Kong

Methadone maintenance programs are good examples of harm-reduction efforts because heroin addicts stabilized on methadone have been found to be able to reduce illicit drug use and criminality and improve their life condition, even though they have not achieved abstinence. While excluding the criterion of abstinence allows the harm-reduction approach to distinguish itself from traditional treatment, little research attention has been paid to the relationship between methadone programs and abstinence-oriented treatment programs. This research note reports some of the findings of a study of 77 former male clients of SARDA, a voluntary residential treatment agency in Hong Kong, pertaining to such a relationship. Findings suggest that a client's previous participation in the Outpatient Methadone Program of the Department of Health could facilitate successful outcome in his subsequent participation in SARDA's treatment program and help him to continue his drug-free status in the post-SARDA treatment period. Conceptual and policy implications of the findings are discussed. [Translations are provided in the International Abstracts Section of this issue.]