Background

Health services, especially TB and HIV services, are likely to encounter a proportion of people who are drug users. Similarly, services dealing with drug users and the criminal justice system will encounter a proportion of people who have become infected with HIV and/or TB.

The need to attend multiple services acts as a barrier to treatment in drug users. Currently TB and HIV services and services for drug users in many countries are likely to be organized very separately and are not as integrated as they could be.

Key issues

Policies and strategies for delivering HIV services to injecting drug users are well established in many countries. This is not the case for TB services, since the emerging problem of the double burden of TB/HIV among drug users was recognized relatively recently.

However, research and strategies for addressing problem drug use other than injecting behaviour are less well established.

Because of the intertwined nature of these conditions, the service delivery response needs to be exible and integrated. A useful definition of integrated care is “an organizational process of coordination which seeks to achieve seamless and continuous care, tailored to the patients' needs and based on a holistic view of the patient” (72).

Summary of findings

The many social and health service barriers to accessing prevention and care services for drug users may result in lengthy delays in seeking health care. Successful outcomes to care are further complicated by lower levels of adherence to prescribed treatments.

Daily drug use, alcohol dependence and depression are associated factors that can complicate care and treatment. Stigma against drug users among health workers, law enforcement personnel and social service workers also contributes to poor outcomes (73), such as the forced registration of drug users within mandatory drug treatment programmes in many countries. Women who inject drugs are much more likely to delay approaching health facilities than men who inject (74). Studies in the United States of America indicate that injecting drug users may have lower and suboptimal access to HIV care and may be less likely to receive antiretroviral therapy than other populations (74–76).

Evidence for combining TB and HIV treatment services in settings with high HIV prevalence is backed up by policy (6) and practice (77). The advantages of integrated co-located TB/HIV services, especially for injecting drug users, have been reviewed (23).

A UNAIDS study (78) of HIV prevention activities in seven low- and medium-income settings that had achieved successfully high coverage among injecting drug users showed that common features included:

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using harm reduction principles to develop local programmes;

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advocacy efforts need to be given priority, adequately staffed and funded;

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the role of law enforcement services is crucial for success;

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there could be differences in each setting resulting in different services and approaches to attract injecting drug users to a programme;

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a single programme can be replicated to address the needs of injecting drug users in other districts, cities and provinces;

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convenience of access; and

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involvement of injecting drug users.

Table 1 shows the suggested TB/HIV activities that could be provided at each entry point into the services that drug users may access.

Table 1

Treatment delivery should be ensured in the setting that is the most accessible, non-stigmatising and convenient for the drug user and most likely to promote adherence.

Background

Drug users are very likely to experience prison or other places of detention including compulsory detoxification and rehabilitation centres since non-prescribed opiates and amphetamine-type stimulants are illegal in almost all countries and criminal behaviour is linked with obtaining illicit drugs.

Key issues

Prisons and other places of detention are congregate settings where some of the most vulnerable drug users are exposed to some of the highest risks for TB and HIV coinfection while often having the least access to health care and the fewest resources in terms of political commitment and investment.

Summary of findings

Prisoners have a high risk of transmission of TB and HIV infections and a high rate of dual TB/HIV infection (22,79,80) for reasons such as the following (22,32,80–82).

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They receive people who are more likely to already have TB and/or HIV infection.

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Prisoners are more likely to be infected by TB because of overcrowding, lack of natural ventilation, poor nutrition and poor infection control.

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Prisoners are less likely to have access to health care services for prevention and treatment.

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Prisons are a high-risk environment for becoming infected with HIV through injecting practices and sexual behaviour.

Multiple links between prisoners and general communities include high turnover and release of prisoners, millions of family visits per year and the movement of prison staff. Infection can therefore be transmitted in either direction. Treatment risks being discontinued on transfer into, out of and between places of detention. However, prison can also be an important site for initiating and providing effective antiretroviral therapy (83).

Multidrug-resistant TB may be more common in prison settings in some countries, particularly in the countries in the Commonwealth of Independent States, where rates of multidrug-resistant TB are among the highest in the world and are higher among prisoners (22).

Several WHO guidelines and manuals have recommendations for preventing and treating both TB (32) and HIV (30) among prisoners.

Background

Treatment for TB and HIV is highly effective, but drug users have not derived the most benefit. This loss of benefit is related to lifestyle issues and the reluctance of physicians to initiate therapy based on their prediction of poor adherence. Evidence increasingly indicates that adherence interventions targeting drug users can result in treatment completion rates as good as those for other people. Poor adherence leads to the development of drug resistance, and this may soon be seen as a failure not primarily of the drug user but of the health system to provide appropriate adherence interventions.

Key issues

There is a common perception that drug users do not adhere to therapy, but active drug use is not a valid reason for denying access to treatment and care. Nevertheless, programmes must be available to support drug users. For example, sometimes drug users cannot enter drug rehabilitation unless they can prove they do not have TB. At the same time, people with TB may not be allowed to use drugs (and are often not offered health care assistance for withdrawal) in TB hospitals, threatening treatment adherence (Open Society Institute, New York, USA, personal communication in response to guideline consultation, May 2008).

Summary of findings

A literature search was carried out to identify studies that examined adherence to pharmaceutical therapy for HIV, TB and opiate substitution therapy among drug users (see Annex 2 for search strategy).

Injecting drug users, in particular, have increased risks of morbidity, mortality and antiretroviral drug resistance (23,84), poor access to health care and poor adherence to antiretroviral therapy (85) and to TB treatment (86).

Drug users engaged in stable care with experienced personnel and adequate support can adhere to long-term treatment and can have clinical outcomes comparable to those of people who do not use drugs.

Barriers to adherence vary between settings, so services should consult with users and their representatives first to find the most effective ways to overcome them and the best local solutions. Evidence indicates effectiveness for adherence reminders, adherence counselling, contingency management, supervised therapy, opioid substitution therapy and ancillary services.

Adherence reminders are usually inexpensive and include beepers, alarms, timers and watches, blister packs, pill boxes and calendars. They may be useful for people for whom a major reason for missed doses is “forgetting”, but they have little impact.

Evidence is mixed for the effect and persistence of the benefits of adherence counselling. One reason is that interventions are heterogeneous, ranging from high-cost cognitive behavioural interventions delivered by professionals to peer-led support (87–90).

Contingency management means that participants are rewarded for positive health behaviour and sanctions are imposed for negative health behaviour. Such interventions may take the form of direct financial compensation, token economy systems such as vouchers, positive reinforcing medications (most commonly methadone) and material incentives (such as bus tokens or electronic items). Community-based directly observed isoniazid preventive therapy with cash incentives showed 89% completion rates (91). The use of financial incentives in the United States of America and Canada has substantially increased compliance with TB screening and adherence to TB treatment among injecting drug users (92,93), although questions of ethics (using payments to buy drugs) and sustainability are associated with this approach. Costs are usually high and the effect can be short-lived (94,95).

Supervised therapy: the introduction of directly observed therapy for isoniazid preventive therapy in injecting drug users led to a reduction in the incidence of latent TB in a prospective observational study (96). A randomized trial in the United States of America showed that supervised care for isoniazid preventive therapy had 80% completion rates (97). Opioid substitution therapy in voluntary settings has been shown to improve relapse to opioid use, decrease recidivism, improve adherence to antiretroviral therapy for people living with HIV and decrease HIV risk-taking behaviour (89,98,99).

Providing methadone with directly observed therapy for latent TB infection, with or without counselling, was associated with a four-fold improvement of isoniazid treatment completion (55), and providing isoniazid preventive therapy for TB infection and directly observed therapy in methadone maintenance clinics has been shown to be a cost-effective approach to preventing TB (100,101).

Ancillary services: complex factors such as social stability, education, housing situation and socioeconomic status can impact adherence. Services may include provision of primary care, social services or general friendship and social support that help to provide some level of lifestyle stability and may improve adherence. Co-location of multiple services, particularly for drug users, has been shown to result in improved health outcomes in the United States of America (57,102). Social support has been associated with improved outcomes in directly observed therapy programmes for treating TB in Thailand and New York City (103,104).

Background

The stigma against drug users in a sometimes abusive and criminalizing environment may encourage health care services to cite comorbidity as an excuse not to provide life-saving treatments to drug users. These treatments may also prevent infections from being transmitted to other people.

Key issues

There are particular concerns about hepatitis C infection leading to reluctance to start treatment for drug users.

Summary of findings

Many studies have demonstrated the high prevalence of comorbidity, especially viral hepatitis B and viral hepatitis C among injecting drug users. The prevalence of hepatitis C among injecting drug users in many countries, such as Brazil, Canada, China and the United States of America, approaches 100% (105–108).

Although there are few data on the prevalence of coinfection of HIV and TB with hepatitis B or hepatitis C in drug users, this can be expected to occur in a significant proportion, particularly injecting drug users. Some studies have started to address the potential challenges of comorbidity. For example, a study of isoniazid-associated hepatotoxicity among people coinfected with hepatitis C virus showed no increased risk of transaminase elevation or drug discontinuation (109).

Neither medication for TB nor antiretroviral therapy are contraindicated among drug users who have hepatitis B or hepatitis C (36,50,53,110). Existing WHO guidelines provide recommendations on treatment modifications and monitoring in the presence of acute and chronic hepatitis infection (50,110).

Many types of comorbidity such as mental health problems, hepatitis and ongoing illicit drug use may require increased health care supervision, and global, regional or national clinical guidelines should be followed in managing comorbidity.