Estimates of the national trend of drugs use during 2000-2030 in China: A population-based mathematical model

Trends and associated factors of HIV, HCV and syphilis infection among different drug users in the China-Vietnam border area: an 11-year cross-sectional study (2010-2020)

BACKGROUND

Data on recent human immunodeficiency virus (HIV), hepatitis C virus (HCV) and syphilis prevalence among drug users in the Southwest China are sparse despite the high burden of drug use. This study aims at assessing the prevalence trends and related factors of HIV, HCV and syphilis infection among different drug users in the China-Vietnam border area.

METHODS

A continuous cross-sectional survey was conducted among drug users from 2010 to 2020 in the China-Vietnam border area. Chi-square trend tests were used to assess the trend of HIV, HCV and syphilis prevalence and the proportion for drug type used by drug users. Multivariate logistic regression was used to identify associated factors of HIV, HCV and syphilis infection in different drug users.

RESULTS

In this study, a total of 28,951 drug users were included, of which 27,893 (96.45%) male, 15,660 (54.09%) aged 13-34 years, 24,543 (84.77%) heroin-only users, 2062 (7.12%) synthetic drug-only (SD-only) users and 2346 (8.10%) poly-drug users. From 2010 to 2020, the proportion of heroin-only users decreased from 87.79% to 75.46%, whereas SD-only users and poly-drug users increased from 5.16% to 16.03%, and from 7.05% to 8.52%, respectively. The prevalence of HIV, HCV, and syphilis during the study period declined from 12.76%, 60.37% and 5.72% to 4.35%, 53.29% and 4.53%, respectively, among heroin-only users and declined from 18.30%, 66.67% and 15.69% to 6.95%, 27.81% and 5.35%, respectively, among poly-drug users; however, the prevalence of HIV and HCV among SD-only users increased from 0.89% and 8.93% to 2.84% and 18.75%, respectively. Having ever injected drugs and needle sharing were common associated factors for both HIV and HCV infection among poly-drug users and heroin-only users. Aged ≥ 35 years old was an associated factor for HIV, HCV and syphilis infection among the SD-only users. Female drug users were at high risk of contracting syphilis among three different drug users.

CONCLUSIONS

The prevalence of HIV, HCV and syphilis among heroin-only users and poly-drug users decreased during the study period. However, the prevalence of HIV and HCV among SD-only users increased. Comprehensive intervention strategies, particularly focusing on the SD-only users are needed in order to bring down the disease burden in this population in the China-Vietnam border areas.

A Scoping Review of Drug Epidemic Models

The phenomenon of drug epidemics has been a global issue in the past decades, causing enormous damages to the physical and mental health of drug users and social well-being. Despite great efforts to curb drug epidemics at the governmental or social level, the total number of drug users has still been on the rise in recent years, along with illicit production and trafficking around the world. Inspired by dynamical epidemic models of infectious disease, a flourishment of promising results has been observed in the exploration of drug epidemic models. In this review, we aim to provide a scoping review of all existing drug epidemic modeling studies, and it has been shown that most studies focused on analyses of theoretical behaviors of the model systems, lacking emphasis on practical applications in real settings. We found that the drug epidemic models were characterized by a longer time scale, no incubation period, no significant prevention vaccines interfered, and population specificity. This review could assist policymakers and public health workers in gaining deeper insights into modeling tools, and help modelers improve their works, thus narrowing gaps between mathematical epidemiology and public health studies.

Determination of amphetamines, ketamine and their metabolites in hair with high-speed grinding and solid-phase microextraction followed by LC-MS

A novel hair sample pre-treatment method based on high-speed grinding and solid-phase microextraction (SPME) had been applied for the determination of amphetamines, ketamine and their metabolites in hair samples by liquid chromatography-mass spectrometry (LC-MS). A 20 mg sample of hair was ground with 2 mL of saturated sodium carbonate solution using a high-efficiency hair grinder with 70 Hz oscillation for 2 min at 4 °C. After centrifuging, 1.5 mL of the supernatant was transferred and treated with SPME by direct immersion (DI-SPME). The target analytes extracted by fibre were desorbed and analysed using LC-MS. Under the optimum conditions, a recovery of 90.2%–95.8% was obtained for all analytes. The analytical method was linear for all analytes in the range from 0.2 to 10 ng/mg with the correlation coefficient ranging from 0.9985 to 0.9993. The detection limits for all analytes were estimated to be 0.067 ng/mg. The accuracy (mean relative error) was within ±6.9% and the precision (relative standard error) was less than 6.8%. The combination of high-speed grinding of hair and SPME had the advantages of being easy to perform, environment-friendly and high in detection sensitivity. The proposed method offered an alternative analytical approach for the sensitive detection of drugs in hair samples for forensic purposes.

Key Points

The SPME was involved for the determination of drugs in hair with LC-MS.

The hair high-speed grinding combined with SPME was firstly developed.

Good linearity, sensitivity, recovery and precision were achieved.

A Systematic Review of Simulation Models to Track and Address the Opioid Crisis

The opioid overdose crisis is driven by an intersecting set of social, structural, and economic forces. Simulation models offer a tool to help us understand and address this complex, dynamic, and nonlinear social phenomenon. We conducted a systematic review of the literature on simulation models of opioid use and overdose up to September 2019. We extracted modeling types, target populations, interventions, and findings. Further, we created a database of model parameters used for model calibration, and evaluated study transparency and reproducibility. Of the 1,398 articles screened, we identified 88 eligible articles. The most frequent types of models were compartmental (36%), Markov (20%), system dynamics (16%), and Agent-Based models (16%). Over a third evaluated intervention cost-effectiveness (40%), and another third (39%) focused on treatment and harm reduction services for people with opioid use disorder (OUD). More than half (61%) discussed calibrating their models to empirical data, and 31% discussed validation approaches used in their modeling process. From the 63 studies that provided model parameters, we extracted the data sources on opioid use, OUD, OUD treatment, cessation/relapse, emergency medical services, and mortality parameters. This database offers a tool that future modelers can use to identify potential model inputs and evaluate comparability of their models to prior work. Future applications of simulation models to this field should actively tackle key methodological challenges, including the potential for bias in the choice of parameter inputs, investment in model calibration and validation, and transparency in the assumptions and mechanics of simulation models to facilitate reproducibility.

Valuation system connectivity is correlated with poly-drug use in young adults

Poly-drug consumption contributes to fatal overdose in more than half of all poly-drug users. Analyzing decision-making networks may give insight into the motivations behind poly-drug use. We correlated average functional connectivity of the valuation system (VS), executive control system (ECS) and valuation-control complex (VCC) in a large population sample (n = 992) with drug use behaviour. VS connectivity is correlated with sedative use, ECS connectivity is separately correlated with hallucinogens and opiates. Network connectivity is also correlated with drug use via two-way interactions with other substances including alcohol and tobacco. These preliminary findings can contribute to our understanding of the common combinations of substance co-use and associated neural patterns.

Stereotypes of Social Groups in Mainland China in Terms of Warmth and Competence: Evidence from a Large Undergraduate Sample

The Stereotype Content Model (SCM) has been validated in multiple countries and regions. However, previous validation studies in China have been limited by small sample size. The current research increased the sample size (n = 184 in the pilot study; n₁ = 1315 and n₂ = 268 in the formal study) to validate the SCM in mainland China in study 1. Supporting the SCM, 41 social groups were clustered into four quadrants based on warmth and competence dimensions. 35 of the 41 target groups (85.37%) receive ambivalent stereotype. Perceived warmth and competence were positively correlated (r = 0.585, p < 0.001). Status and competence were positively related (r = 0.81, p < 0.001), and competition and warmth were negatively related (r = −0.77, p < 0.001). In addition, 24 typical social groups were selected and a list of stereotype words for these groups was developed in study 2 (n₁ = 48, n₂ = 52). The implications of the emerging social groups and the applications of this stereotype word list are discussed.

Illicit synthetic opioid consumption in Asia and the Pacific: Assessing the risks of a potential outbreak

BACKGROUND

Illegally manufactured potent synthetic opioids (IMPSO) like fentanyl have contributed to rises in overdose deaths in parts of North America and Europe. While many of these substances are produced in Asia, there is little evidence they have entered markets there. We consider the susceptibility to IMPSO's encroachment in markets in the Asia-Pacific region.

METHODS

Our analysis focuses on Australia, China, India, and Myanmar. Using a mixed-methods approach comprising interviews, literature review, and secondary data analyses, we examine factors facilitating or impeding incursion of IMPSO. Finally, we illustrate the potential for IMPSO fatalities in Australia.

RESULTS

Australia reports some signs of three facilitating factors to IMPSO's emergence: 1) existing illicit opioid markets, 2) disruption of opioid supply, and 3) user preferences. The other three countries report only existing illicit opioid markets. While diverted pharmaceutical opioids are a noted problem in Australia and India, heroin is the dominant opioid in all four countries. There are divergent trends in heroin use, with use declining in China, increasing in India, and stable in Australia and Myanmar. If IMPSO diffused in Australia as in North America from 2014 to 2018, and our assumptions generally hold, deaths from IMPSO could range from 1500-5700 over a five-year period.

CONCLUSIONS

This analysis and illustrative calculations serve as an early indication for policymakers. With the exception of Australia, many countries in the region fail to properly record overdose deaths or monitor changes in local drug markets. Early assessment and monitoring can give officials a better understanding of these changing threats.

Modeling the Dynamics of Drug Spreading in China

Drug abuse remains one of the major public health issues at the global level. In this article, we propose a drug epidemic model with a complete addiction–rehabilitation–recovery process, which allows the initiation of new users under the influence of drug addicts undergoing treatment and hidden drug addicts. We first conduct qualitative analyses of the dynamical behaviors of the model, including the existence and positivity of the solutions, the basic reproduction number, global asymptotic stabilities of both the drug-free and the drug-persistent equilibria, as well as sensitivity analysis. Then we use the model to predict the drug epidemic in China during 2020–2030. Finally, we numerically simulate the potential impact of intervention strategies on different drug users. The results show that the drug epidemic will decrease significantly during 2020−2030, and the most effective intervention strategy to eliminate drug epidemics is to strengthen the investigation and rehabilitation admission of hidden drug users.

Sociodemographic Factors Associated With HIV/HCV High-Risk Behaviors Among People Who Use Drugs on Methadone Maintenance Treatment: A 10-Year Observational Study

Background: Sociodemographic factors have an impact worldwide on the behavior of people who use drugs (PWUD). This study attempts to clarify the sociodemographic factors related to HIV/HCV high-risk behaviors (injection drug use, syringe sharing, and multiple sex partners) among PWUD on methadone maintenance treatment (MMT) in the long term. Methods: The 13,300 PWUD recruited into the MMT program were followed during 2006-2015. Generalized estimating equations were used to examine the relationship between sociodemographic characteristics and HIV/HCV high-risk behaviors. Results: We found that male (vs. female), living alone (vs. living with family or relatives), temporary income, financial support from family/friends, and financial support from social welfare (vs. regular salary) were positively associated with injection drug use. Age of initial drug use was negatively associated with injection drug use and syringe sharing. For both genders, being unmarried (vs. married or in cohabitation), living with friends, living alone (vs. living with family or relatives), temporary income, financial supports from family/friends (vs. regular salary), being employed (vs. unemployed/between jobs) was positively associated. In contrast, age at baseline was negatively associated with having multiple sexual partners for both genders. Ethnic of non-Han (vs. Han) was positively associated with having multiple sexual partners simply for males. Being divorced or widowed (vs. married or cohabitated) was positively associated with having multiple sexual partners merely for females. Conclusion: HIV/HCV high-risk behaviors correlated with certain sociodemographic factors of PWUD receiving MMT. There is a need for improving the well-being, employment, and housing status of PWUD on MMT to reduce their HIV/HCV risk behaviors.

Estimation of the impact of changing drug-use trend on HIV, hepatitis C and syphilis epidemics among people who use synthetic drug-only, polydrug and heroin-only during 2005-2035 in China: modelling study

OBJECTIVE

The rapid expansion of the recreational drug market becomes a global health concern. It is worrying that the bacterial and viral infection epidemics linking to drug use may worsen accordingly. This study aimed to estimate the impacts of changing trend and behaviours of using heroin only, synthetic drug (SD) only and polydrug (using SD and heroin concurrently) on HIV, hepatitis C virus (HCV) and syphilis epidemics among people who use drugs in China by 2035.

METHODS

We constructed a compartmental model to estimate HIV, HCV and syphilis epidemics in the dynamic drug-use trend by three scenarios: SD-only use, heroin-only use and polydrug use based on Monte Carlo simulations. The parameters for the model were collected from a comprehensive literature search.

RESULTS

Our model estimated that polydrug use led to the highest HIV and HCV prevalence among three drug-use patterns. The prevalences were projected to increase from 10.9% (95% CI 10.2% to 11.5%) and 61.7% (95% CI 59.4% to 62.5%) in 2005 to 19.0% (95% CI 17.3% to 20.7%) and 69.1% (95% CI 67.3% to 69.5%), respectively, in 2035 among people using polydrug. Similarly, HIV and HCV prevalence in the SD-only group were projected to increase from 0.4% (95% CI 0.3% to 0.4%) and 19.5% (95% CI 19.4% to 21.7%) to 1.8% (95% CI 1.4 to 2.1%) and 33.7% (95% CI 33.2% to 34.9%) in 2005-2035. Conversely, HIV prevalence in the heroin-only group was projected to decrease from 8.0% (95% CI 7.6% to 8.1%) to 2.2% (95% CI 2.0% to 2.3%) in 2005-2035. Syphilis prevalence was estimated to remain unchanged in all population groups within this time frame. It was projected that the proportion of HIV transmitted by sexual transmission will increase compared with unsafe injection transmission in all people who use drugs from 2005 to 2035.

CONCLUSION

Our modelling suggests that polydrug use is projected to lead to the highest HIV and HCV disease burden by 2035, and the proportion of HIV transmitted by sexual transmission will increase. Current HIV intervention among people using heroin seems effective according to our estimation.

Relationship Between Buddhist Belief and Suicide Risk in Chinese Persons Undergoing Methadone Maintenance Therapy for Heroin Dependence

BACKGROUND

In western countries, there is a negative association between religious belief and suicide risk, while in China this association is positive. Nevertheless, few data are available on the association between one specific type of religion and suicide risk, which might be different from the overall positive religion-suicide association in China. This study examined the association between Buddhist belief and suicide risk in Chinese persons receiving methadone maintenance therapy (MMT) for heroin dependence.

METHODS

In total, 61 Buddhist believers and 425 age, gender, and clinic frequency-matched non-religious believers were selected from a sample of patients with heroin dependence treated in three MMT clinics in Wuhan, China. The suicidality module of the Chinese version of the Mini-international Neuropsychiatric Interview 5.0 was used to assess current suicide risk. Patients' demographic and clinical characteristics were also collected. Multiple ordinary logistic regression was used to analyze the association between Buddhist belief and current suicide risk, controlling for the confounding effects of demographic and clinical factors.

RESULTS

In Chinese patients receiving MMT for heroin dependence, Buddhist believers had significantly higher levels of current suicide risk than non-religious believers (low: 45.9% vs. 24.7%, medium: 4.9% vs. 3.5%, high: 19.7% vs. 12.5%, P < 0.001). After adjusting for demographic and clinical covariates (including depressive symptoms), Buddhist belief was still significantly associated with an increase in the level of current suicide risk (OR: 2.98, P < 0.001).

CONCLUSION

Buddhist belief is significantly associated with elevated current suicide risk in Chinese patients receiving MMT for heroin independence. In Chinese MMT clinics, patients with Buddhist belief may have a high current suicide risk and a timely psychiatric assessment and crisis intervention (when necessary) should be provided to these patients.

Heroin Abuse and/or HIV Infection Dysregulate Plasma Exosomal miRNAs

Exosomes play an important role in cell-to-cell communication as they can transfer functional molecules such as microRNAs (miRNAs) from one cell to another, exerting biological and immunological functions. Here, we investigated the impact of HIV infection and/or heroin use on the expression of the miRNAs in plasma exosomes. We found that HIV infection or heroin use upregulated the majority (98%) of a panel of plasma exosomal miRNAs associated with immune regulation and inflammation. We also observed the enhanced effect of HIV infection and heroin use on some of these upregulated miRNAs. Our further investigation showed that the levels of four of neuro-inflammation-related miRNAs (146a, 126, 21, and let-7a) were higher in HIV-infected heroin users as compared with the control subjects. These findings indicate that the dysregulations of the plasma exosomal miRNAs support further studies to determine the role of the miRNAs in HIV and/or heroin use-mediated immune modulation and neuro-inflammation. Graphical abstract.