Sulfate triple-oxygen-isotope evidence confirming oceanic oxygenation 570 million years ago.

The largest negative inorganic carbon isotope excursion in Earth's history, namely the Ediacaran Shuram Excursion (SE), closely followed by early animal radiation, has been widely interpreted as a consequence of oceanic oxidation. However, the primary nature of the signature, source of oxidants, and tempo of the event remain contested. Here, we show that carbonate-associated sulfate (CAS) from three different paleocontinents all have conspicuous negative 17O anomalies (Δ'17OCAS values down to -0.53‰) during the SE. Furthermore, the Δ'17OCAS varies in correlation with its corresponding δ34SCAS and δ18OCAS as well as the carbonate δ13Ccarb, decreasing initially followed by a recovery over the ~7-Myr SE duration. In a box-model examination, we argue for a period of sustained water-column ventilation and consequently enhanced sulfur oxidation in the SE ocean. Our findings reveal a direct involvement of mass-anomalously 17O-depleted atmospheric O2 in marine sulfate formation and thus a primary global oceanic oxygenation event during the SE.

ZNF503 combined with GATA3 is a prognostic factor in triple-negative breast cancer.

PURPOSE: Triple-negative breast cancer (TNBC) is a subtype of breast cancer with poor prognosis. Therefore, there is an urgent need to identify prognostic markers to improve current treatment and therapeutic strategies. The transcriptional factor ZNF503 has been reported to promote aggressive breast cancer development through the down-regulation of GATA3 expression and has been identified as a candidate predictive marker. In this study, we explored whether ZNF503 and GATA3 could serve as prognostic markers independently or in combination. MATERIAL AND METHODS: We performed a survival analysis of 989 breast cancer patients from The Cancer Genome Atlas (TCGA), and validated the findings in 202 breast cancer patients from tissue microarray (TMA). RESULTS: In TCGA database, the mRNA expression of GATA3 and ZNF503 could not predict TNBC prognosis alone, though the ratio index, ZNF503/GATA3 could be a novel prognostic biomarker in TNBC patients. In TMA database, we detected the protein expression of ZNF503 and GATA3 and found that the combination of the two genes, ZNF503-GATA3, significantly improved the predictive ability of clinical outcomes. CONCLUSIONS: The results indicated that the binding index of ZNF503 and GATA3 could be used as a prognostic biomarker in TNBC.

Job Satisfaction Among Methadone Maintenance Treatment Clinic Service Providers in Jiangsu, China: A Cross-sectional Survey.

OBJECTIVE: Service providers' job satisfaction is critical to the stability of the work force and thereby the effectiveness of methadone maintenance treatment (MMT) programs. This study aimed to explore MMT clinic service providers' job satisfaction and associated factors in Jiangsu, China. METHODS: This secondary study used baseline data of a randomized interventional trial implemented in Jiangsu, China. A survey was conducted among 76 MMT service providers using the computer-assisted self-interview (CASI) method. Job satisfaction responses were assessed via a 30-item scale, with a higher score indicating a higher level of job satisfaction. Perceived institutional support and perceived stigma due to working with drug users were measured using a 9-item scale. Correlation and multiple linear regression analyses were performed to identify factors associated with job satisfaction. RESULTS: Correlation analyses found a significant association between job satisfaction and having professional experience in the prevention and control of HIV, other sexually transmitted infections, or other infectious diseases (P = 0.046). Multiple regression analyses revealed that working at MMT clinics affiliated with Center for Disease Control and Prevention sites was associated with a lower level of job satisfaction (P = 0.014), and perception of greater institutional support (P = 0.001) was associated with a higher level of job satisfaction. CONCLUSION: Job satisfaction among MMT clinic service providers was moderate in our study. Our findings suggest that institutional support for providers should be improved, and that acquisition of additional expertise should be encouraged.

An intervention trial targeting methadone maintenance treatment providers to improve clients' treatment retention in China.

BACKGROUND: Service providers including doctors, nurses, and other healthcare professionals play an essential role in methadone maintenance treatment (MMT). This study evaluated the impact of an intervention targeting MMT providers on their clients' treatment retention. METHODS: This study was conducted in 68 MMT clinics in five provinces of China with 36 clients randomly selected from each clinic. The clinics were randomized to intervention or control condition. The MMT CARE intervention started with group sessions to enhance providers' communication skills. The trained providers were encouraged to conduct individual sessions with clients to promote treatment engagement. The outcomes, which include client retention (main outcome) and their reception of provider-delivered individual sessions (process outcome), were measured over a 24-month period. RESULTS: Significantly fewer intervention clients dropped out from MMT than control clients during the study period (31% vs. 41%; p < 0.0001). Dropout hazard was significantly lower in the intervention condition compared to the control condition (HR = 0.71, 95% CI: 0.57, 0.89). More intervention clients had individual sessions than control clients (93% vs. 70%; p < 0.0001). Having individual sessions was associated with a significantly lower dropout hazard (HR = 0.30, 95% CI: 0.23, 0.40). The intervention clients had a significantly lower dropout hazard than the control clients if they started the individual sessions during the first six months (HR = 0.68, 95% CI: 0.51, 0.90). CONCLUSIONS: The MMT CARE intervention focusing on provider capacity building has demonstrated efficacy in reducing clients' treatment dropout. This study sheds light on MMT service improvement in China and other global community-based harm reduction programs.

Identifying apparent local stable isotope equilibrium in a complex non-equilibrium system.

RATIONALE: Although being out of equilibrium, biomolecules in organisms have the potential to approach isotope equilibrium locally because enzymatic reactions are intrinsically reversible. A rigorous approach that can describe isotope distribution among biomolecules and their apparent deviation from equilibrium state is lacking, however. METHODS: Applying the concept of distance matrix in graph theory, we propose that apparent local isotope equilibrium among a subset of biomolecules can be assessed using an apparent fractionation difference (|Δα|) matrix, in which the differences between the observed isotope composition (δ') and the calculated equilibrium fractionation factor (1000lnß) can be more rigorously evaluated than by using a previous approach for multiple biomolecules. We tested our |Δα| matrix approach by re-analyzing published data of different amino acids (AAs) in potato and in green alga. RESULTS: Our re-analysis shows that biosynthesis pathways could be the reason for an apparently close-to-equilibrium relationship inside AA families in potato leaves. Different biosynthesis/degradation pathways in tubers may have led to the observed isotope distribution difference between potato leaves and tubers. The analysis of data from green algae does not support the conclusion that AAs are further from equilibrium in glucose-cultured green algae than in the autotrophic ones. CONCLUSIONS: Application of the |Δα| matrix can help us to locate potential reversible reactions or reaction networks in a complex system such as a metabolic system. The same approach can be broadly applied to all complex systems that have multiple components, e.g. geochemical or atmospheric systems of early Earth or other planets.

WITHDRAWN: LncRNA-HOTAIR Activates Tumor Cell Proliferation and Migration by Suppressing MiR-326 in Cervical Cancer.

Cervical cancer is the second most common malignant cancer in females. Recent findings indicate that LncRNA-HOTAIR played a crucial role in tumor progression. In our present study, we aimed to explore the regulating role of HOTAIR in the progression of cervical cancer. The expression of HOTAIR was found up-regulated in cervical cancer tissues and cell lines (Hela, CasKi, Me180 and C-33A) compared with the normal tissues and normal cervical cell line (Ect1/E6E7). To examine the function of HOTAIR, gene knockdown (KD) was performed using HOTAIR short hairpin RNAs (shRNAs). HOTAIR shRNA significantly suppressed cells proliferation and migration in Hela cells. Besides that, the targeting relationship between HOTAIR and miR-326 was firstly revealed by bioinformatics prediction. Simultaneously, suppressed expression of miR-326 was detected in tumor tissues and cell lines compared with the control. Then, suppressed expression level of miR-326 was elevated by adding miR-326 mimic in cervical cancer cells transfected with LncR-HOTAIR. Similarly, increased expression level of miR-326 was reduced by adding miR-326 inhibitor in cervical cancer cells transfected with HOTAIR shRNA. The targeting relationship between HOTAIR and miR-326 was further been confirmed through the luciferase report assay. Moreover, there existed a negative relationship between the expression of HOTAIR and miR-326. In addition, enhanced cell proliferation and migration abilities were suppressed by HOTAIR shRNA in cells transfected with miR-326 inhibitor. Finally, the in vivo experiment revealed that tumor growth and metastasis could also be inhibited by HOTAIR shRNA. Our present study elucidated the regulating role of HOTAIR/miR-326 axis in cervical cancer progression and provided a new potential therapeutic strategy for cervical cancer.

Psychoactive Substance Use among Methadone Maintenance Therapy Clients in China.

A proportion of methadone maintenance therapy (MMT) clients in China shifted their substance use habit from opiate to psychoactive substances. The objective of this study was to examine the pattern and associated factors of psychoactive substance use among MMT clients. The study was conducted among 2,448 clients from 68 MMT clinics of China. The type and frequency of psychoactive substance use were self-reported. About 38.1% (N=933) of the participants reported psychoactive substance use in lifetime, and 6.5% (N=158) in the previous 30 days. The most commonly used psychoactive substances were sedative/hypnotic/antidiarrheal agent and amphetamine. Psychoactive substance use in the past 30 days was correlated with younger age, recent heroin use, having psychoactive substance using friend(s), and depressive symptoms. The finding suggested that urinalysis of psychoactive substances should be routinely administered in the MMT clinics. Young clients, concurrent heroin users, and clients with depressive symptoms deserve more screening and intervention efforts.

Client Acceptability for Integrating Antiretroviral Therapy in Methadone Maintenance Therapy Clinics in Sichuan, China.

BACKGROUND: Using methadone maintenance therapy (MMT) clinics to deliver antiretroviral therapy (ART) has proven to be effective for promoting treatment initiation and adherence in drug users living with HIV. OBJECTIVES: The objective of this study was to investigate the HIV-positive client acceptability of integrated ART services and to identify the reasons for and factors associated with service acceptability. METHODS: A total of 86 HIV-positive MMT clients were recruited from 12 MMT clinics in Sichuan Province, China. They participated in a cross-sectional survey that queried their willingness to receive seven different types of MMT-based ART services. The reasons for their willingness/unwillingness to accept these services were documented. The association between service acceptability and background characteristics was examined. RESULTS: The most accepted integrated services were ART-related counseling (75.6%) and referral (73.2%). Concerns regarding the provider's lack of ART expertise and confidentiality issues were common barriers for the acceptance of MMT-based ART services. A trust relationship with MMT providers was a reason for service acceptance. Service acceptability was associated with a poorer perceived health status. Conclusions/Importance: ART-related services, based on the client perspective, can be delivered at MMT clinics. However, service provider training and the protection of confidentiality must be strengthened for the effective implementation of integrated service delivery.

Report on Provider-Client Interaction From 68 Methadone Maintenance Clinics in China.

Provider-client interaction is an integral of clinical practice and central to the delivery of high-quality medical care. This article examines factors related to the provider-client interaction in the context of methadone maintenance treatment (MMT). Data were collected from 68 MMT clinics in China. In total, 418 service providers participated in the survey. Linear mixed effects regression models were performed to identify factors associated with provider-client interaction. It was observed that negative attitude toward drug users was associated with lower level of provider-client interaction and less time spent with each client. Other factors associated with lower level of interaction included being female, being younger, being a nurse, and fewer years in medical field. Higher provider-client interaction was associated with provider reported job satisfaction. The findings of this study call for a need to address provider negative attitudes that can impact provider-client interaction and the effectiveness of MMT. Future intervention efforts targeting MMT providers should be tailored by gender, provider type, and medical experiences.

HIV seroconversion and risk factors among drug users receiving methadone maintenance treatment in China: A qualitative study.

OBJECTIVE: We sought to explore the experiences of drug users in China who were recently diagnosed with HIV infection while engaged in methadone maintenance treatment (MMT) and to better understand their perceptions of MMT, HIV risk, and HIV prevention. METHODS: We recruited clients of MMT clinics in Chongqing and Kunming who had a baseline HIV-negative test result upon entry to MMT and had been diagnosed with HIV within the past 12 months. We conducted semi-structured qualitative interviews and thematic data analysis to identify situations and factors that increased HIV risk. RESULTS: Among the 27 participants who were interviewed, 15 believed their infection was due to injection drug use, 7 attributed their infection to sexual contact, and 5 were unsure as to how they became infected. High risk behaviors were common; 18 participants continued to use drugs during treatment, and 10 engaged in unprotected sex. Common themes were the difficulty of drug abstinence despite receiving MMT, social pressure to continue using drugs, and low knowledge of effective HIV prevention measures. CONCLUSION: While MMT is effective in reducing drug usage and needle sharing, many clients remain at risk of HIV infection due to continued injection drug use and unprotected sex. Clients may benefit from additional counseling on HIV prevention methods as well as structural interventions to increase the availability of clean injection equipment.

Baseline HCV Antibody Prevalence and Risk Factors among Drug Users in China's National Methadone Maintenance Treatment Program.

BACKGROUND: Hepatitis C virus (HCV) is the most common viral infection among injecting drug users worldwide. We aimed to assess HCV antibody prevalence and associated risk factors among clients in the Chinese national methadone maintenance treatment (MMT) program. METHODS: Data from 296,209 clients who enrolled in the national MMT program between March 2004 and December 2012 were analyzed to assess HCV antibody prevalence, associated risk factors, and geographical distribution. RESULTS: Anti-HCV screening was positive for 54.6% of clients upon MMT entry between 2004 and 2012. HCV antibody prevalence at entry declined from 66.8% in 2005 to 45.9% in 2012. The most significant predictors of HCV seropositivity were injecting drug use (adjusted odds ratio [AOR]: 8.34, 95% confidence interval [CI]: 8.17-8.52, p<0.0001) and a history of drug use ≥9 years (AOR: 2.01, 95% CI: 1.96-2.06, p<0.0001). Being female, of Uyghur or Zhuang ethnicity, and unmarried were identified as demographic risk factors (all p-values<0.0001). Of the 28 provincial-level divisions included in the study, we found that 5 divisions had HCV antibody prevalence above 70% and 20 divisions above 50%. The HCV screening rate within 6 months after MMT entry greatly increased from 30.4% in 2004 to 93.1% in 2012. CONCLUSIONS: The current HCV antibody prevalence remains alarmingly high among MMT clients throughout most provincial-level divisions in China, particularly among injecting drug users and females. A comprehensive prevention strategy is needed to control the HCV epidemic among MMT clients in China.

[Factors influencing access to methadone maintenance treatment among injecting drug users attending antiretroviral treatment clinics in two counties, Yunnan province].

OBJECTIVE: To understand the demographic characteristics of HIV infected injecting drug users (IDUs) with access to antiretroviral therapy (ART) and to identify the factors influencing their access to methadone maintenance treatment (MMT). METHODS: Outpatients infected with HIV through injecting drug use were selected from the ART clinics in 2 counties in Yunnan province. They were divided into 2 groups, MMT group and non MMT group. Descriptive epidemiologic analysis was conducted on their demographic characteristics, disease history and high risk behaviors and logistic regression analysis was done to identify the factors associated with the access to MMT. RESULTS: Among 635 IDUs (536 males, 99 females) surveyed, 247 received MMT (38.9%), 388 received no MMT(61.1%). The median age was 40.33 years and the median diagnosed HIV infection time was 6.08 years. Multivariate logistic regression indicated that being female (OR=2.40, 95%CI:1.00-5.74), educational level of junior high school (OR=3.28, 95%CI:1.75-6.14), educational level of senior high school or above (OR=7.10, 95%CI:1.90-26.62), more than 6 years of diagnosed HIV infection history (OR=3.84, 95% CI:2.11-6.98) and HCV positive (OR=6.21, 95% CI:3.06-12.58) were the positive factors influencing IDUs' access to MMT. However, being married (OR=0.38, 95%CI:0.20-0.72) or being employed (OR=0.01, 95%CI:0.00-0.02) were the negative factors influencing IDUs' access to MMT. CONCLUSION: The proportion of HIV infected IDUs who received MMT in ART clinics was still very low in the two counties, targeted intervention measures should be taken to increase the MMT coverage, especially among those who are married or employed.

[Impacts of antiretroviral treatment on drug use and high risk sexual behaviors among HIV-positive MMT clients].

OBJECTIVE: To explore the impacts of antiretroviral treatment on drug use and high risk sexual behaviors among HIV-positive MMT clients. METHODS: A cross-sectional study was conducted in patients undergoing ART (ART-experienced) and patients not undergoing ART (ART-naive) attending MMT in 5 clinics in Yunnan Honghe and Dehong prefectures in 2014. A questionnaire was designed to collect socio-demographic characteristics, ART and MMT information and sexual and drug use behaviors within 3 months before the investigation was conducted. Logistic regression analysis was conducted to identify the predictors for drug use and risky sexual behaviors. RESULTS: A total of 328 cases were included in the analysis, among which 202 were ART-experienced and 126 were ART-naÏve. Among 152 respondents who were sexually active, 61 (40.1%) reported having unprotected sex (UPS) with their regular partners in the prior 3 months. A total of 57.6% (189/328) of the respondents used drugs in the prior 3 months. Multiple logistic regression analysis revealed that younger than 35 years old (OR = 3.57, 95% CI: 1.23-10.37), fertility desire (OR = 4.47, 95% CI: 1.49-13.41), partner being HIV-positive (OR = 4.62, 95% CI: 1.80-11.86), length of MMT attendance less than 5 years (OR = 2.92, 95% CI: 1.14-7.53), agreed that it was necessary to use condom no matter the viral load is high or low (OR = 0.14, 95% CI: 0.04-0.51) were protective factors of UPS in the prior 3 months. Multiple logistic regression analysis revealed that being Han (OR = 0.46, 95% CI: 0.24-0.89), feeling having good health status (OR = 0.39, 95% CI: 0.18-0.85), being enrolled in ART (OR = 0.32, 95% CI: 0.17-0.60) were protective factors for drug use in the prior three months, having contact with drug using friends (OR = 4.41, 95% CI: 2.31-8.29), having experience of missing an MMT dose (OR = 3.47, 95% CI: 1.92-6.29), and not satisfied with current MMT dose (OR = 13.92, 95% CI: 3.24-59.93) were risk factors for drug use during the prior three months. CONCLUSION: ART was not associated with risky sexual behavior and drug use in the prior 3 months in this population. Future interventions should promote ART among this population, and provide education at the same time to prevent the emergence of cross infections and drug-resistant strains.

[Impact of antiretroviral therapy on drug-using and high risk sexual behaviors among HIV-positive methadone maintenance treatment clients: a qualitative study].

OBJECTIVE: To understand that whether initiation of antiretroviral therapy (ART) would impact on the change and its reasons regarding the HIV-related high risk behaviors among HIV-positive clients who attending the methadone maintenance treatment (MMT). METHODS: In-depth interviews were conducted among 34 MMT clients in Yunnan province who were under ART. The related contents would include information on general demographic charicteristics, HIV infection,MMT, number of sexual partners before and after ART, sexual behavior and frequency of condom use, drug use, needle sharing, changes in risk behaviors before and after the ART, reasons for high-risk behavior, of the clients. RESULTS: The average age of the interviewees was 38.5 years, and most of them were male (70.6%). The clients under this study all admitted that the frequencies of unsafe sex and needle sharing did not increase after the ART initiation, with the main reasons as increasing HIV related awareness, the use of methadone, high accessibility of free condoms and access to clean needles etc. However, 12 of 34 reported being relapsed and 3 reported inconsistent condom use. The interaction of ART and dosage of methadone were connected to the episodes of relapsing and the ART optimism would result in inconsistent condom use. CONCLUSION: No evidence supported that the ART initiation would increase the risk behaviors among the HIV-infected MMT clients. However, attention needs to be paid to the new challenges caused by high expectation of ART.

Who uses methadone services in China? Monitoring the world's largest methadone programme.

AIMS: To describe the data collected by the Chinese methadone maintenance treatment (MMT) system and the characteristics of clients entering the programme. DESIGN: Descriptive study using routinely collected data from the MMT data management system for the period March 2004 and March 2010. SETTING: All MMT clinics in China. PARTICIPANTS: Clients who enrolled for services between March 2004 and March 2010. MEASUREMENTS: Routinely collected data included: demographic information; drug use, sexual and criminal behaviours; status of infection with human immunodeficiency virus (HIV), hepatitis C virus (HCV) and syphilis; random urine-opiate test results; and the daily methadone dose received. Differences among clients by year were examined. FINDINGS: During the period examined, there were 251,974 clients attending 684 clinics in 27 provinces. Overall, the mean age was 34.4 years, 83.8% were male, 70.2% were unemployed, 75% had ever injected drugs, 17% had shared needles and 7.4% were HIV-positive. The profile of clients changed over time, with fewer HIV-positive individuals, fewer injecting drug users, fewer needle-sharers, fewer females and fewer unemployed. Half the clients dropped out within 6 months. The average final dose received was 49.4 mg. The estimated probability of interrupting treatment before 6 months was 52.5%. CONCLUSIONS: The profile of clients enrolling in methadone maintenance treatment in China is continually changing and appears to be associated with reduced risk of HIV. High dropout in the programme may limit its effectiveness. The availability of a centralized, real-time data system was extremely useful for monitoring the progress of the Chinese methadone maintenance treatment programme.

Factors associated with depression and anxiety among patients attending community-based methadone maintenance treatment in China.

AIM: To estimate the prevalence of, and identify factors associated with, depression and anxiety among community-based methadone maintenance treatment (MMT) clients in China. DESIGN: A cross-sectional survey. SETTING: Nine MMT clinics, three each from three Chinese provinces (Yunnan, Anhui and Jiangsu) between October 2008 and February 2009. PARTICIPANTS: A total of 1301 MMT clients. MEASUREMENTS: A questionnaire, including the Zung Self-Rating Depression Scale (SDS) and Zung Self-Rating Anxiety Scale (SAS), and on-site urine drug testing. FINDINGS: The prevalence of depression (SDS score≥53) and anxiety (SAS score≥50) in our sample was 38.3% [95% confidence interval (CI)=35.7, 40.9] and 18.4% (95% CI=16.3, 20.5), respectively, with 14.2% (95% CI=12.3, 16.1) displaying symptoms of both. Sample prevalence rates for depression [mean=49.69, standard deviation (SD)=10.34] and anxiety (mean=40.98, SD=10.66) were higher than the national average for each (t(0.05/2, 1300)=19.2, P<0.001 and t(0.05/2, 1300)=8.0, P<0.001, respectively). Employing multi-level modelling techniques, gender (P=0.03) and employment status (P<0.001) were found to be associated significantly with depression in a single-level model; however, in a multi-level mixed model, only employment status (P<0.001) was associated with depression. Gender (P=0.03), education level (P=0.02), marital status (P=0.04), employment status (P<0.001), positive urine drug test results (P=0.02) and daily methadone dose (P<0.001) were found to be associated significantly with anxiety in a single-level model, while only employment status (P<0.01) and positive results for the urine drug test (P=0.04) were associated with anxiety in a multi-level mixed model. CONCLUSIONS: A considerable proportion of methadone maintenance treatment clients in China have experienced depression and anxiety during treatment. There is a need to provide tailored mental health interventions for this high-risk population.

Needle and syringe exchange programmes and prevalence of HIV infection among intravenous drug users in China.

AIM: To examine the association between needle and syringe exchange programme (NSEP) participation and human immunodeficiency virus (HIV) infection among intravenous drug users (IDUs) in China. DESIGN: Cross-sectional survey study design. SETTING: Six counties with active NSEP were selected from each of the seven provinces with active NSEP sampled, resulting in a sample of 42 counties in China. PARTICIPANTS: Subjects were aged more than 18 years and had injected drugs in the past month before the survey, but were excluded if they were currently enrolled in methadone maintenance treatment in order to avoid mixed effects. MEASUREMENTS: HIV prevalence was the primary measure. Odds ratios (ORs), 95% confidence intervals (CIs) and P-values were calculated to evaluate associations between HIV infection and NSEP participation. FINDINGS: A total of 3494 IDUs were interviewed, of whom 1928 (55.2%) were NSEP attendees (meaning they had attended NSEP at least once in their life-time). The unadjusted HIV prevalence was 13.9% among NSEP attendees and 16.5% among NSEP non-attendees (meaning IDUs who had never used NSEP services). After adjusting for potential confounders and taking into account the variation between counties, NSEP non-attendees were 1.67 times more likely to be HIV-positive compared to NSEP attendees (OR=1.67, CI=1.19-2.32, P=0.0031). CONCLUSIONS: Participation in needle and syringe exchange programmes was associated with a substantially lower risk of HIV infection among intravenous drug users in China. Needle and syringe exchange programmes should be expanded to include those who are needle and syringe exchange programme non-attendees.

Retention and its predictors among methadone maintenance treatment clients in China: a six-year cohort study.

BACKGROUND: To investigate factors associated with retention among the first cohort of drug users attending methadone maintenance treatment (MMT) clinics in China. METHODS: A six-year cohort of 1511 drug users was enrolled in the first 8 MMT clinics in China in 2004 and followed between March, 2004 and December, 2010. Six-year retention rates were calculated and compared by methadone dosage, clinic location, and length of follow-up. Factors associated with retention were evaluated using Cox proportional hazard regression models. RESULTS: The overall retention rate over 6-year was 35.7%. Highest drop-out occurred within the first 12 months of treatment. The retention rates for the 6-year by low (≤ 30 mg/day), medium (31-60 mg/day), and high (>60 mg/day) methadone dosage groups were 20.8%, 34.8% and 53.2%, respectively (p < 0.001). The highest 6-year retention rate among eight clinics was 43.8%, while the lowest one was 17.7% (p < 0.001). The results from Cox proportional hazard models indicate that clients having >30 mg daily methadone dosage (p < 0.001), having relatives receiving MMT (p = 0.027), and having >10% urine morphine positive result (p < 0.001) were more likely to be retained in MMT over the six-year period. It has also found that drug injection (p = 0.005) and needle sharing (p < 0.0001) were significantly associated with better retention. CONCLUSIONS: Health workers should adjust individuals' methadone dosages as a method to prevent early treatment termination. Further studies are needed to explore the impact of severity of opiate addiction on long-term retention of MMT clients. Careful assessment of drug users upon MMT enrollment may be helpful for providing additional care to clients.

[Club-based drug use and its associated risk factors among HIV-positive methadone maintenance treatment clients].

OBJECTIVE: To describe club-based drug use and to explore the determinants on those HIV-positive methadone maintenance treatment (MMT) clients. METHODS: This study was conducted in 5 MMT clinics in Yunnan province and 612 MMT clients who met the survey criteria were recruited for the study. Urine sample was tested as a biological marker to identify if heroin, methamphetamine, methylene-dioxy-methyl-amphetamine, buprenorphine or benzodiazepine had been used. RESULTS: The average age among the 612 clients was 38.9 ± 6.3 years. Among these, 78.9% were males, with the average years of education as 8.0 ± 3.4 years. There were 60.5% clients who had good relationship with their families. 153 (25.0%) clients reported having used club-related drugs in the last 12 months. Results from the urine test showed that the positive rate on morphine was 14.4%, while the positive rate for club-related drugs was 26.6%. Factors as residential area, casual sexual partners, retention on MMT and occasionally use of heroin were associated with urine results on club-related drugs and the prevalence of self-reported club drug use (P < 0.05). CONCLUSION: Club-related drug use was common among HIV-positive MMT clients. Inspection and supervision for club-related drugs and the education and intervention programs on related high risk behaviors should be strengthened.