Chinese Medical Journal 2013;126(8):1517-1521
HIV infection among new synthetic drug abusers: a pilot study in Beijing
Correspondence to:Dr. JIA Zhong-wei,National Institution on Drug Dependence, Peking University, Beijing 100191, China; Takemi Program in International Health, Department of Global Health and Population, Harvard School of Public Health, Boston, MA, USA (Tel: 86-10-82802460. Fax:86-10-62032624. E-mail:email@example.com)
human immunodeficiency virus; syphilis; new synthetic drugs; heroin drug
Background Following the increased human immunodeficiency virus (HIV) notification (infection) rates via sexual transmission and increased abuse of new synthetic drugs instead of heroin in China, a study on HIV infections and risk factors among synthetic drugs and heroin users in Beijing was conducted to provide a cue for further development of targets and strategies of HIV/AIDS control and prevention for different drug populations.
Methods A total of 428 subjects including 224 heroin users and 204 new synthetic drug users was recruited from communities in Beijing by convenience sampling. A c2 test was used to compare HIV and syphilis infections between the two subpopulations. Logistic regression models were used to evaluate factors related to HIV, syphilis infections and abuse of synthetic drugs.
Results Unbalanced distributions of demographics were detected between the two subpopulations. Compared with heroin users, most users of synthetic drugs were migrants, single and of younger age (age £30 years). Ten HIV infections and twenty-four syphilis infections were confirmed among 428 subjects. No significant difference in HIV infection was found between the two subpopulations (crude odds ratio (OR) =0.46, 95% confidence interval (CI): 0.07–15.80 and adjusted odds ratio (AOR) =1.26, 95% CI: 0.09–18.28) while four times as many syphilis infections were identified among users of synthetics drugs (AOR=3.92, 95% CI: 1.06–14.56). HIV and syphilis infections appeared to work synergistically. The migrants who were of Han ethnicity, single and who had stayed in Beijing for more than six months were more likely to abuse synthetics drugs.
Conclusions The new synthetic drug users and heroin users are different subpopulations. We optimistically speculate that HIV has not yet been introduced into the former in Beijing, but considering higher syphilis infections in synthetic drug users and the role of syphilis in HIV infection, synthetic drug users, as a possible and important driver of the HIV/AIDS epidemic in Beijing, should be paid more attention in HIV prevention and control strategies.
Drug abuse and human immunodeficiency virus/ acquired immune deficiency syndrome (HIV/AIDS) are substantial public health concerns in metropolitan cities in China, including Beijing.1,2 By the end of 2009, Beijing had 10 071 reported HIV/AIDS cases3 of which 23.1% were infected through intravenous drug injection.4,5 However, national surveillance of notifiable infectious diseases showed that the percentages of total annual reported cases attributed to the sexual route6 doubled from 41.4% to 87.1%7 while transmission by drug injection decreased from 38.5% to 28.4% in the period between 2007 and 2011.8,9 The transmission route of HIV/AIDS seems to be changing.
At the same time, some evidence suggests that the epidemic of China’s drug use is changing with new synthetic drugs becoming the second most widely consumed drugs in China.10,11 From 2003 to 2009, heroin use decreased by 12.8% and synthetic drug use increased by 918.8% among all users while heroin and synthetic drug use among the new users increased by 52.3% and 860.7%, respectively.12
New synthetic drugs,13 known collectively as “club drugs” which have been produced artificially, generally include crystal methamphetamine (also known as “ice”), 3,4-methylenedioxymethamphetamine (MDMA, also known as “ecstasy”), ketamine, and others. A number of studies have investigated the association between heroin use and HIV/AIDS,14-17 but to the best of our knowledge, considerably fewer studies on HIV infection among users of new synthetic drugs have been found in China.18 This work aimed to conduct a pilot study on HIV infection among users of new synthetic drugs in Beijing and provide the implication and understanding for HIV/AIDS prevention and control.
Subjects and recruitment process
A total of 428 addicts including 224 heroin users and 204 synthetic drug users were recruited from the communities in Beijing where drug users typically clustered (clubs or karaoke bars) by convenience sampling between August and November of 2010. Investigators informed the drug users of the goals of the study as well as their right to refuse to take part in this study. The investigators were also drug users who had strong desires to seek treatment for their drug addiction and usually act as liaisons between drug users and government or non-government organizations. After drug users fully understood the study, a written informed consent was provided to and signed by the participants. All subjects were asked to complete a questionnaire and to provide a blood sample for HIV and syphilis tests. Each participant was assigned a unique and confidential identification code linking the questionnaire and specimens.
All recruited subjects were then classified into the following groups: (1) heroin drug users were defined as those who only took heroin and new synthetic drug users were defined as those who use methamphetamine, ecstasy, or ketamine. (2) Migrant population was distinguished from permanent residents by their household registers.19 The questionnaire collected demographic characteristics, and behaviors and information on interventions (such as peer education, or condom education, or general education for prevention of HIV/AIDS) related to HIV.
Serum specimens from all participants were collected and tested for HIV and syphilis antibodies. For HIV testing, samples that were reactive in the first ELISA test (HIV [1+2] Ag/Ab ELISA; Beijing WANTAI Biological Pharmacy Enterprise Co., Ltd), were retested using another ELISA kit (Vironostika HIV Uni-Form II Ag/Ab; Murex Biotech Ltd) based on different antigens. Suspected cases whose primary double screenings for HIV antigen were positive were confirmed using an HIV-1/2 Western blot immune assay (HIV BLOT, version 2.2, MP Biomedicals LLC). A participant whose rapid plasma regain circle card test (RPR, JINHAO Biological Pharmacy Enterprise Co., Ltd) and Treponema pallidum particle agglutination test (TPPA, Fujirebio Inc., Japan) were both positive was confirmed as a definite case for syphilis.
All data were double-entered and validated in EpiData 3.0 package (EPI Data for Windows; EPI Data Association, Odense, Denmark). We first estimated the difference in HIV and syphilis infections between the heroin-user group and the synthetic drugs-user group by Pearson c2 test or Fisher’s exact tests (two-tailed) for categorical variables. Unconditional Logistic regression models were used to evaluate risk factors related to HIV and syphilis infections. Multivariable models were also explored to identify independent risk factors associated with synthetic drug users. The investigated factors included ethnicity (Han or minority), syphilis infection, age (30 or under, between 31 and 45, over 45), marital status (partnered or single), registered residency (permanent resident or migrant), injection history (yes or no), had sexual behavior last month (yes or no), HIV intervention (yes or no), and HIV knowledge (scored 6 or higher or less than 6). Relative risks were calculated as crude odds ratios and adjusted odds ratios with 95% CI. We took P <0.05 to indicate statistical significance. All statistical analyses were conducted using SPSS version 18.0 for Windows (SPSS Inc., Chicago, IL, USA).
Demographic characteristics of subjects
The study yielded a sample of 428 verified drug users (204 synthetic drug users, 47.7%; 224 heroin users, 52.3%). All subjects undertook questionnaires and serum testing. Unequal distributions of demographics, behaviors and interventions related to HIV were detected among heroin users and synthetic drug users (Table 1). Methamphetamine users accounted for 93% (190/204) of synthetic drug users. The mean age of synthetic drug users was 6.4 years younger ((32.2±8.5) years) than that of heroin users ((38.6±7.8) years). In comparison with heroin users, more synthetic drug users were younger (£30 years) (50% vs. 17%, OR=4.96, 95% CI: 3.17–7.75), migrant (75% vs. 57%, OR=2.19, 95% CI: 1.45–3.31) and single (45% vs. 26%, OR=2.25, 95% CI: 1.50–3.38; Table 1). Users of synthetic drugs were more likely to have sexual behavior recently (OR=2.37, 95% CI: 1.60–3.50) and higher proportion of condom use (OR=2.03, 95% CI: 1.07–3.82 and OR=2.30, 95% CI: 1.27–4.19), but they had less HIV knowledge (OR=0.32, 95% CI: 0.15–0.45) and received less intervention related to HIV/AIDS (OR=0.36, 95% CI: 0.24–0.53 and OR=0.47, 95% CI: 0.29–0.77; Table 1).
Table 1. Demographics, behaviors and interventions associated with HIV infection for subjects in Beijing, 2010
Factors related to HIV infection and syphilis
Ten HIV infections (2.3%) including seven heroin users (3.1%) and three methamphetamine users (1.5%) were confirmed among all 428 subjects. No significant difference in HIV infection was detected between the synthetic drug users and heroin users, either on its own with crude odds ratio (OR) of 0.46 (95% CI: 0.07–15.80) or after adjusting for other factors with adjusted odds ratio (AOR) of 1.26 (95% CI: 0.09–18.28) for synthetic drug users (Tables 1 and 2). Syphilis infection seemed positively associated with HIV infection although the adjusted odds ratio has a wide confidence interval (AOR=15.63, 95% CI: 1.76–138.88). Injecting history (AOR=13.04, 95% CI: 1.43–118.78) and ethnicity (AOR=15.35, 95% CI: 2.15–109.36) were also found to be associated with HIV infection (Table 2).
Twenty-four syphilis infections (5.6%) including eight heroin users (3.6%) and sixteen synthetics drug users (7.6%) were also identified. The synthetic drug users had a four-fold higher relative risk of syphilis infection than heroin users (AOR=3.92, 95% CI: 1.06–14.56, Table 2). Compared with younger participants (£30 years), syphilis infection was more likely to occur in the middle age group (31 years £ age £ 45 years, AOR=3.99, 95% CI: 1.31–12.19, Table 2).
Table 2. Logistic regression analysis for factors associated with HIV infection and syphilis (AOR (95% CI))
Factors related to synthetic drug users
Subgroup analysis indicated that most synthetic drug users were younger people (£30 years) in both migrants and permanent residents (Table 3). For migrants, single people (AOR=2.32, 95% CI: 1.18–4.59) and those who had been staying in Beijing for more than 6 months (AOR=3.00, 95% CI: 1.67–5.39) were more likely to use synthetics drugs. However, migrants who are of Han ethnicity used less synthetics drugs (AOR=0.14, 95% CI: 0.05–0.43, Table 3).
Table 3. Logistic regression analysis for factors associated with new synthetic drugs use (AOR (95% CI))
Our study discloses that HIV and syphilis infection in the heroin subpopulation are 3.1% and 3.6%, respectively. National sentinel surveillance suggested that the HIV infection rate remained at 9.0%–10.0% and syphilis fluctuated between 3.5% and 4.5% during 2007–2009.20 We observed consistent syphilis infection and lower HIV infection in comparison with the national surveillance. A possible reason for the lower HIV infection in heroin users in our study might be that our recruitment covered all heroin users whether or not they took the drug through an injection route which is one of the highest risks of HIV infection.21,22 Another explanation might be from “The People’s War on Drugs” initiative23 which aimed at solving the country’s heroin abuse problems by providing drug use prevention education, drug addiction treatment and rehabilitation and by strengthening drug use control and prevention at all levels of the government.
Fewer domestic studies on HIV infection in synthetic drug users have been conducted.1,16 Our study indicates that HIV infection is lower in the synthetic drug users in comparison with the heroin users, though the difference is not statistically significant, possibly due to a small number of HIV positive cases (Table 1). Needle-sharing, a known risk factor of HIV infection in drug users,24-26 is low in the synthetic drug users (3%) but higher in heroin users (55%, Table 1). Slightly higher adherence of condom use (42% vs. 26%, Table 1) might also contribute to the lower HIV infection. Lower HIV infection among synthetic drug users might also be because HIV seeds had not yet been introduced into this population, but this hypothesis needs further studies. However, this study found that synthetic drug users have more sexual activities with less HIV interventions (Table 1). Given the association between syphilis and HIV infection, a higher syphilis infection rate and poor knowledge of HIV in the synthetic drug users, the work indicates that synthetic drug users form a potential HIV/AIDS driving subpopulation in Beijing.
Another finding of our study is that heroin users and synthetic drug users are notably different subpopulations. More than half (51%) of the synthetic drug users are less than 30 years old while only 17% of heroin users are in that stratum. The reason may be related to access of synthetic drugs, which are notoriously easy to find and buy,10,27,28 and to high work pressure.29 To some extent, this factor could also explain why single individuals and migrants, which accounted for about 24% of all synthetic drug users in this study, are more likely to use synthetic drugs.30 Other possible contributing factors include curiosity, fear of decreasing sexual activity because of the side effect of heroin31,32 and less knowledge about the harms of this kind of new synthetic drugs.33 As a result, most users believe that the adverse effects of synthetic drugs are short-lived and that these types of drugs are commonly not addictive.34
Several limitations must be acknowledged in this study. First, this is a pilot study of HIV infection in synthetic drug users and the results cannot represent the general situation in Beijing. Second, participants might misreport information on their own sexual behaviors, but we do not believe that any single bias can significantly affect the overall results at the population level. Third, the differences found between heroin users and synthetic drug users, as well as differences between this study and other studies might be due to differences in sampling, which constrained our efforts to compare some results. Additionally, the potential causal pathway between synthetic drugs and HIV infection cannot be ascertained in this cross-sectional study with a small sample size of HIV positive subjects.35,36 However, exploratory findings from this study will motivate further researches into synthetic drug users and help tailor HIV risk reduction intervention programs in specific subgroups of drug users. Finally, polydrug use was not considered in our study.
Despite the aforementioned limitations, our study provides the implications that new synthetic drug users are different from heroin users. The slightly lower HIV infection in this population found might be because the HIV seed has not been transmitted to, given synthetic drugs were strongly associated with the increased likelihood of higher risk unsafe sexual behaviors,37 new synthetic drug users should be another important subpopulation for HIV prevention and control in Beijing.
Acknowledgements: We would like to thank Dr. MA Wei (School of Medine, Shandong University) and Sophy Zhang (Simon Fraser University, Canada) for their comments in the preparation of the work.
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