Статья для зачёта - 2010 год / Статья для зачёта - 2010 год

262 Tim Rhodes et al.

Table 6 Multivariable risk factors for antibodies to hepatitis C by city.

		Logistic regression model			GEE
Variable		OR	95% CI	P-value1		OR	95% CI	P-value2
Moscow*
Sex group
Male	1.0				1.0
Female	0.9		0.54–1.57		0.8		0.48–1.23	< 0.001
Female sex worker	0.2		0.10–0.58	0.01	0.2		0.08–0.50
Ever injected home made drugs?
No	1.0				1.0
Yes	3.2		1.48–6.72	0.00	2.2		0.99–4.71	0.05
Ever injected with used needles/syringes?
No	1.0				1.0			< 0.001
Yes	2.3		1.41–3.69	0.00	2.5		1.57–3.85
Registered as an IDU at Narcology Service?
No	1.0				1.0
Yes	1.4		0.70–2.84	0.32	1.9		1.12–3.13	0.02
History of drug treatment?
No	1.0				1.0
Yes	1.8		1.05–2.98	0.03	1.7		0.99–2.87	0.06
Volgograd‡
Sex group
Male	1.0				1.0
Female	0.7		0.43–1.26	< 0.001	0.7		0.51–0.95
Female sex worker	0.1		0.07–0.33		0.3		0.11–0.66	0.01
Duration of injection (years)
2 years or less	1.0				1.0
3–5	2.4		1.41–4.18		2.4		1.55–3.66
6–9	3.0		1.66–5.36		2.7		1.37–5.41
10+	1.6		0.74–3.28	< 0.001	1.6		0.83–3.02	0.00
Ever injected home made drugs?
No	1.0				1.0
Yes	1.7		0.97–2.88	0.06	1.9		1.21–2.90	0.01
Registered as an IDU at narcology service?
No	1.0			< 0.001	1.0
Yes	2.5		1.40–4.31		2.2		0.99–5.48	0.05
Barnaul†
Education
Secondary	1.0				1.0
Higher	0.7		0.39–1.24	0.22	0.5		0.30–0.97	0.04
Duration of injection (years)
2 years or less	1.0				1.0
3–5	1.2		0.65–2.08		1.2		0.79–1.78
6–9	3.3		1.82–6.11		2.6		1.07–6.24
10+	5.3		2.86–9.83	< 0.001	3.3		1.33–7.98	0.04
Ever injected home made drugs
No	1.0				1.0
Yes	1.9		0.90–4.01	0.08	2.0		1.07–3.65	0.03
Average number of times reuse of the same needle?
1	1.0				1.0
2+	2.1		1.39–3.13	0.03	1.0		0.58–1.57	0.86
Injected with used needles/syringes in the last 4 weeks
No	1.0				1.0
Yes	1.37		0.77–2.44	0.28	1.8		1.05–2.97	0.03

OR = odds ratio 95% CI = 95% confidence interval. 1P value derived from likelihood ratio test. 2P value derived from Wald test. *Moscow: logistic regression model adjusted for sex group variable, ever injected home made drugs (mak or vint), ever injected with used needles/syringes and history of drug treatment. The GEE final model is adjusted for sex group variable, ever injected with used needles/syringe and being registered as an IDU at a narcology service.

‡Volgograd: logistic regression model adjusted for sex group variable, duration of injection and being registered as an IDU at a narcology service. The GEE final model is adjusted for sex group variable, ever injected home made drugs and duration of injection. †Barnaul: logistic regression model adjusted for duration of injection and average number of times inject with the same needle/syringe. The GEE final model is adjusted for education, duration of injection, ever injected home made drugs and injection with used needles/syringes in the last four.

© 2006 The Authors. Journal compilation © 2006 Society for the Study of Addiction

Addiction, 101, 252–266

positive for anti-HCV (OR 2.7, 95% CI 1.37–5.41). There were no differences in significant risk factors between the GEE and logistic regression models.

In Barnaul, the adjusted GEE model indicated that IDUs who had attended higher education were less likely to be anti-HCV positive (OR = 0.5, 95% CI 0.3–0.97) than those who had not. As with Volgograd, prevalence and odds of anti-HCV increased with duration of injection, with those who reported injecting longer than 10 years being over three times as likely to test be anti-HCV positive than recent initiates into injecting (OR = 3.3, 95% CI 1.33–7.98). Also similar to Volgograd, those who reported ever having injected home-produced drugs were twice as likely to be anti-HCV positive than those who had not (OR = 2.0, 95% CI 1.07–3.65). Finally, IDUs in Barnaul who reported injecting with used needles/syringes in the last 4 weeks were almost twice as likely to be antiHCV positive (OR = 1.8, 95% CI 1.05–2.97) than those who had not. The adjusted logistic regression model indicated a much stronger association between testing positive for anti-HCV and duration of injection than the GEE model. It also indicated increased odds associated with reuse of needles more than twice (OR = 2.1, 95% CI 1.39–3.13), whereas no association was found with the GEE model (OR = 1.0, 95% CI 0.58–1.57). Conversely, no association was found for ever having injected with used needles/syringes in the adjusted logistic regression model (OR = 1.4, 95% CI 0.77–2.44) but was for the GEE model (OR = 1.8, 95% CI 1.05–2.97).

Syphilis prevalence

The prevalence of syphilis was 8% (32/414, 95% CI 5.1– 10.3%) in Moscow, 20% (93/438, 95% CI 16.2–23.5%) in Volgograd and 6% (32/494, 95% CI 4.3–8.7%) in Barnaul (Table 5). Over half (85/156, 54%) of those found positive to T. pallidum (which indicates past or current infection) reported never having had an STI. The mean (SD) age of those testing positive to syphilis was 26 (5.9) years. Three-quarters (74%) of those positive to syphilis were HCV positive and 10% HIV positive.

DISCUSSION

This study indicates varied prevalence of HIV (at around 10% or more in two cities), high prevalence of HCV and varied prevalence of syphilis (at 20% in one city) among the largest community-recruited sample of IDUs in Russia. Two-thirds of IDUs were unaware of their positive HIV status, and half were unaware that they had had syphilis. A third of IDUs were unaware of their positive HCV status, and over a half whose last test was reportedly HCV negative were found to be HCV positive. Despite large-scale investment in blood-borne virus screening

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programmes targeting populations at risk in Russia, significant proportions of IDUs (including HIVand HCVpositive IDUs) had not been tested recently for HIV and HCV. Findings point to a large burden of blood-borne and sexually transmitted infection, of which a considerable proportion is undiagnosed, with major public health implications.

Surveillance

Findings underscore the need to foster regular access of IDUs to HIV, HCV and STI screening while maximzsing their self-awareness of HIV, HCV and syphilis status. Targeted behavioural surveillance in community settings can serve to highlight the limits of city screening and testing programmes among hard to reach populations at risk. Of 2 126 958 HIV screening tests undertaken in Moscow in the year of the survey (2003), only 0.3% (6397) were among IDUs, of which 3.2% (202) were HIV positive. Similarly, in Volgograd and Barnaul, HIV tests among IDU represent only 1.7% (5214) and 0.5% (2710) of the total screening tests conducted in 2003 (298 810 in Volgograd and 509 273 in Barnaul). Under 3% of screening tests among IDU in each city were positive (2.6%; 136 in Volgograd; and 2.7%; 75 in Barnaul). Our study findings thus estimate HIV prevalence among IDUs to be over four times higher than estimates derived from screening programmes in Moscow, over three times higher in Barnaul but roughly equivalent in Volgograd, where significantly higher proportions of IDUs reported having had recent HIV tests.

The majority of HIV case reports among injecting drug users are compiled from narcology clinics where HIV testing is obligatory. Case reports are also compiled from clinics for sexually transmitted infections and AIDS centres, when testing can be conducted anonymously for a fee. Anonymous tests are not included in national case reports. Evidence suggests that attendance at narcology clinics has declined in recent years, with greater proportions of IDUs favouring private treatment or selfmedication [14]. The low coverage of drug treatment services and access to anonymous testing may introduce bias into the routine screening system as well as explain the difference in estimated prevalence between our findings and city case reports. These findings emphasize the critical importance of second generation surveillance and targeted surveys of HIV prevalence among communityrecruited samples of injecting drug users as an adjunct to current large-scale HIV screening programmes.

Risk

Our findings suggest while risk factors associated with anti-HIV varied by city, there were some common risk

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264 Tim Rhodes et al.

behaviours across the cities that require urgent attention to prevent further HIV transmission. In Moscow and Volgograd increased odds of HIV were associated with injecting with used needles and syringes. In Barnaul, increased odds of HCV were associated with the use of communal spoons or glasses used for mixing and cooking the drug solute. Some studies point to a relationship between injecting paraphernalia sharing and HCV transmission risk, although the validity of this association has been questioned [15–17]. None the less, our findings highlight an urgent need to reduce levels of direct needle and syringe sharing as well as indirect sharing of injecting paraphernalia among Russian IDUs.

In Moscow we found increased odds of HIV among participants who had been in prison. According to the Russian Ministry of Justice, around three-quarters of prisoners in Russia have a serious disease such as HIV infection and tuberculosis, almost all of whom have experience of drug use [18]. In our view, this highlights a need for introducing the provision of sterile needles and syringes within prisons.

In all cities we found some evidence of increased odds of HCV associated with having injected home-produced drugs. Similar associations have been observed in other Russian cities [2,3]. Although less common since the diffusion of heroin powder into most Russian cities, a combination of anecdotal and qualitative research evidence suggests that a communal pattern of drug preparation and use was, and still remains, a feature of home-pro- duced drug use, and that a pre-existing culture of group use thus also shapes how heroin is used. Group drugusing situations offer greater potential for injecting equipment sharing. We also found some association between official registration as a drug user and anti-HIV and anti-HCV. There is some evidence to suggest that official registration with narcology services can serve to entrench further the social marginalization of IDUs, affecting their capacity to obtain legal employment as well as marking them out as targets for police surveillance [14,19]. Such factors may in part explain the increased odds associated with registration and HIV in Moscow and HCV in Volgograd, and are illustrative of how environmental factors contribute to the social structural production of HIV risk [20].

We found no association between sexual risk behaviours and anti-HIV in any city, suggesting that currently the predominant source of transmission risk is injecting drug use. The reduced odds of HCV among sex workers in Moscow and Volgograd implies that sex workers may be engaging in less risky injecting practices, thereby reducing their chances of acquiring HCV. HIV prevalence was no less among sex workers, perhaps suggesting the potential role of sexual transmission among the population. Additionally, reported condom use was low among all

IDUs, highlighting the need for interventions targeting sexual risk reduction to prevent onwards transmission of HIV and syphilis to non-injecting populations.

Limitations

As the data are drawn from a cross-sectional survey and reported behavioural findings are based on self-reports, any inferences about causality are limited. Using a fieldwork team of current or former drug users with privileged access to the target population may have limited potential bias associated with socially desirable responses. A further limitation inherent in methods of community recruitment of hidden populations is that there is no established sampling frame from which a measure of representativeness can be obtained. We attempted to minimize potential geographic and network bias by ensuring multi-site and multi-network recruitment and by the use of general estimating equation models in the analysis. Few HIV cases in Volgograd led to weaker odds ratios and wide confidence intervals in the HIV risk factor analysis, and these results should therefore be interpreted with greater caution.

Implications

This study indicates the urgent need to scale-up HCV and HIV prevention, as well as sexual risk reduction, for IDUs in Russia. It has been suggested that 10% HIV prevalence can be a critical threshold in the efficient containment of HIV epidemics among IDU, as after this point far greater resources and intervention coverage are required to bring about epidemic containment or reversal [21]. STIs, including untreated syphilis, can accelerate sexual HIV transmission [22]. Additionally, high levels of HIV and HCV coinfection can complicate medical management, including relating to antiretroviral HIV treatment [23]. An estimated 10% of HIV positive IDUs in Russia have access to HIV combination therapy, and under 15% in HIV treatment are IDUs (who make up 80% of all HIV infections) [24].

Moreover, epidemics of HIV, HCV and syphilis among IDUs coincide with wider social and economic transitions in Russia, creating ‘risk environments’ conducive to the spread of blood-borne and sexually transmitted infections [25,26]. Rapid diffusions in drug injecting have coincided with drug trafficking, and population migration and mixing, in the context of economic transition and restructuring, which has increased unemployment and poverty, of which the growth of informal economies is a feature (including drug and sex markets) [27]. At the same time, decline in health and welfare status have coincided with increasing incidence of communicable disease and weakening public health infrastructures which have produced vulnerability in public health capacity and response [24]. Prevention of transmission of blood-borne viruses as well

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as HIV and HCV treatment coverage for IDUs is woefully inadequate. International support for local ‘harm reduction’ has resulted in approximately 70 syringe exchange projects throughout the Federation, but crude estimates suggest these reach under 1%, and at best around 16%, of local IDU populations [2].

Public health-orientated approaches to ‘harm reduction’ in Russia remain in tension with detoxification treatment and law enforcement oriented approaches to tackling drug problems. The linked epidemics of HCV, HIV and syphilis among IDU in Russia are of potential major significance to the public health. The scaling-up of harm reduction, including sexual risk reduction, remains an urgent priority.

Acknowledgements

We are grateful for the support of the UK Department for International Development, who supported this study through programme grants, and to the UK Department of Health who provide core funding to the Centre for Research on Drugs and Health Behaviour. We thank the study participants and the following: Sergei Belikh, Dimitry Blagov, Elvira Demyanyenk, Alexander Fillipov, Nadezhda Gorshkova, Ali Judd, Elena Kudravtseva, Olga Mikhailova, Andrei Rylkov, Anya Sarang, Nelly Savelevna, Lenar Sultanov, Grigoryev Svyatoslav, Mikhail Tichonov, Venyamin Volnov and Konstantin Vyshinsky.

Declaration of interest

This study was undertaken with ethical approval from the Riverside Ethics Committee and with the support of the Russian Ministry of Health National Scientific Centre for Research on Addictions. In addition, there are no conflicts of interest to declare.

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