[Factors associated with retention in a community-based methadone maintenance treatment among heroin addicts].

OBJECTIVE: To explore factors associated with retention in a community-based methadone maintenance treatment (MMT) among heroin addicts in Xichang of Sichuan province. METHODS: All 206 heroin addicts were first admitted to MMT community-based program between March to September 2004. Baseline data of patients characteristics, social function, drug using behaviors, sexual behaviors, dose of methadone and retention were collected. RESULTS: Up to Oct, 2005, all 206 patients contributed 8.98 +/- 5.74 person-months of following-up. The retention rates were 58.7% after 6 months and 34.6% after 12 months respectively. Cox proportional hazard regression model indicated that the employed (HR, 0.60; 95% CI, 0.39 - 0.92), helping family to do housework in past 30 days more than once a day (HR, 0.59; 95% CI, 0.42 - 0.82) and previous self-detoxification > or = 3 times (HR, 0.65; 95% CI, 0.47 - 0.91) were independently associated with retention. CONCLUSION: We should give individual counseling to help heroin addicts increasing compliance.

[A prospective cohort study on human immunodeficiency virus and syphilis seroconversion among injecting drug users].

OBJECTIVE: To study the rate of human immunodeficiency virus (HIV) seroconversion, HIV transmission and related risk factors among injecting drug users (IDUs) in an area of Sichuan province. METHODS: In November 2002, a community-based baseline survey was conducted to recruit 333 HIV-seronegative IDUs for a prospective cohort study in Xichang county of Sichuan province, China. Follow-up visits were carried out every 6 months to study the situation of drug use, sexual behaviors of the IDUs and blood specimens were collected to test for antibodies against HIV and syphilis. RESULTS: During a 24-month follow-up period, cohort retention rate and HIV incidence were 75.7% and 2.53 per 100 person-years [95% confidence interval (CI): 1.10-3.97)], respectively. Multivariate Poisson regression model showed that risk factors which were significantly associated with HIV seroconversion would include: ethnicity (RR = 12.42; 95% CI: 2.72-56.74, P = 0.0012) and needle or syringe sharing in the past 3 months (RR = 4.06; 95% CI: 1.29-12.81, P = 0.0168). Syphilis seroconversion in this cohort was 4.71 per 100 person-years (95% CI: 2.59-6.82). In multivariate Poisson regression being female (RR = 4.42; 95% CI: 1.78-10.99, P = 0.0014) appeared to be the only factor which was significantly associated with syphilis seroconversion. CONCLUSION: Our study results showed that there was a rapid transmission of HIV and syphilis among IDUs in Sichuan province, suggesting that effective intervention should be urgently taken.

[Incidence rates of human immunodeficiency virus and syphilis as well as the rate of retention in a 6-month follow-up study of female sex workers in areas with heavy drug use in Xichang of Sichuan province, China].

OBJECTIVE: To investigate the human immunodeficiency virus (HIV) and syphilis incidence rates as well as the retention rate in a cohort with 6-month follow-up study among female sex workers (FSWs). METHODS: From December, 2004, to January, 2005, a community-based baseline survey was conducted to recruit 343 FSWs for a prospective cohort study in Xichang county of Sichuan province, China. Follow-up visits were conducted at 6 months to analyze risk factors associated with cohort retention for subjects' baseline sociodemographic and sexual behavioral characteristics. Blood specimens were also collected to test antibodies against HIV and syphilis. RESULTS: During the 6-month follow-up period, HIV and syphilis incidence appeared to be 1.00 per 100 person-years and 6.23 per 100 person-years, respectively. The rate of retention in the cohort was 53.6% (184/343). Results from multivariate logistic regression model showed that factors were significantly associated with cohort retention including people with minority ethnic background (OR = 0.36; 95% CI: 0.18-0.74), people having participated in AIDS prevention program (OR = 1.83; 95% CI: 1.17-2.86) or being clients in the last 6 months > or = 50 (OR = 1.75; 95% CI: 1.11-2.77) and having changed living/working place (OR = 0.56; 95% CI: 0.33-0.94). CONCLUSION: The results of this study showed that the syphilis incidence and unprotected sex behavior were high among local FSWs. People belonged to Han nationality, having participated in AIDS prevention program and having a steady living/working place were associated with cohort retention at 6-month follow-up study among FSWs, respectively.

[Single nucleotide polymorphisms of HIV coreceptor CCR5 gene in Chinese Yi ethnic group and its association with HIV infection].

OBJECTIVE: To investigate the single nucleotide polymorphism (SNP) of HIV-1 coreceptor CCR5 gene in Chinese Yi ethnic group and the association between these SNPs and HIV/AIDS. METHODS: Peripheral blood samples of 102 HIV negative persons of Chinese Yi nationality, 87 males amd 15 females, aged 23 (12-37), and 68 HIV carriers, 61 males and 7 females, aged 27 (17-51). The regulatory and structural regions of the HIV coreceptor CCR5 gene were amplified from the genomic DNA by nested PCR, each of the two regions was divided into three gene fragments which were overlapped. High throughput DHPLC was used for screening of unknown mutations in each gene fragment. The PCR products showing different peak traces from wild types in DHPLC were sequenced by forward and reverse primers respectively. The sequences were analyzed with the help of Sequence Navigator software to search for SNP loci. Statistical analysis by SPSS and PPAP softwares were made to study the association between these SNPs and HIV infection. RESULTS: Five SNPs (A77G, G316A, T532C, C921T, and G668A) and a AGA deletion of the 686-688 nucleotides were discovered in the coding region of this gene in Chinese Yi ethnic group. C921T mutation was a nonsense mutation, and the other SNPs (A77G, G316A, T532C, and G668A) are sense mutation, with the amino acid changes of K26R, G106R, C178R, and R223Q. Only the frequency of R223Q allelic gene was high (0.08) but those of the others were low (less than 0.01). There was no significant difference in the allele frequency between the HIV negative and HIV positive groups (all P > 0.05). Five SNP loci (T58934G, G59029A, T59353C, G59402A, and C59653T) were found in the regulatory region of CCR5 gene with high allelic frequencies of 0.1912-0.2941. Between the HIV negative and HIV positive groups, there were no differences in the SNP loc (all P > 0.05). Statistical analysis of the association between the linkage of mutation loci with HIV infection suggested a significant difference in the haplotype frequency of T59353C-G59402A between the HIV negative and HIV positive groups of the Yi population. CONCLUSION: A high throughput screening method of detecting unknown genetic mutation DHPLC can effectively analyze the SNP of CCR5 regulatory and structural regions in Chinese Yi ethnic group.

[Community-based survey on human immunodeficiency virus infection among injection drug users in Sichuan, China].

OBJECTIVE: To investigate prevalence of human immunodeficiency virus (HIV) infection and risk factors for its transmission among injection drug users (IDUs) in Liangshan Yizu Autonomous Prefecture of Sichuan Province, China. METHODS: A community-based survey was conducted to investigate demographic characteristics, pattern and frequency of sharing injection equipment, and sexual behaviors in IDUs. Blood samples were also collected from them to detect for antibodies against HIV and syphilis. RESULTS: A total of 379 subjects were recruited with informed consent for study through community outreach and peer recruiting methods. Their prevalence of HIV infection was 11.3% (43/379). Ethnicity, frequency of sharing syringes and cotton swab during the past three months and syphilis infection associated with HIV infection by univariate analysis using chi-square test. Multivariate logistic regression analysis showed odds ratio of frequency of sharing syringes for HIV infection during the past three months was 2.28 (95% CI 1.18 - 4.43), and that for syphilis infection 3.10 (95% CI 1.48 - 6.48). CONCLUSION: Frequency of sharing syringes during the past three months associated with syphilis and HIV infection.

[Study on the relationship between hepatitis C virus infection and sharing injection equipment, sexual behavior among injecting drug users].

OBJECTIVE: To study hepatitis C virus (HCV) transmission through different modes of sharing injection equipment and sexual behavior among injecting drug users (IDUs) in Liangshan of Sichuan province. METHODS: A community-based survey was conducted to investigate past and current demographic data, injection equipment sharing patterns and sexual behavior of IDUs. Blood samples were also taken to test for HCV. The survey was conducted between Nov 8 and Nov 29, 2002. 379 subjects were screened through outreach recruitment and peer informing. SPSS (11.5) was used for data analysis. RESULTS: HCV prevalence was 71.0% (269/379). Needles or syringes sharing in the past three months and past syphilis infection were strongly associated with HCV transmission after univariate analysis using chi-square test. Trend analysis indicated that HCV infection rate increased along with the increase of needles or syringes sharing, sharing of rinse water and the number of peers sharing the equipments. Data from multivariate logistic regression showed that sharing of needles or syringes and history of syphilis infection were significantly associated with HCV transmission. No significant difference was found between HCV infection and sexual behavior after univariate analysis using chi-square test. CONCLUSION: Further sero-epidemiological prospective cohort studies should be conducted to clarify the relationship between different modes of sharing injection equipment, sexual behavior and HCV infection.

Community-based survey of HCV and HIV coinfection in injection drug abusers in Sichuan Province of China.

AIM: To investigate the prevalence and risk factors of HCV/HIV coinfection in injection drug abusers (IDAs) in Lianshan Yi Autonomous Prefecture of Sichuan province, China. METHODS: From November 8, 2002 to November 29, 2002, a community-based survey was conducted to investigate the demographic characteristics, patterns of shared injectors devices and sexual behaviors in IDAs. Blood samples were also collected to test HCV and HIV infection. A total of 379 subjects were recruited in the study through community outreach and peer recruiting methods. RESULTS: Of the 379 IDAs, the HCV prevalence and HIV prevalence were 71.0% and 11.3%, respectively, and HCV/HIV coinfection was 11.3%. HCV infection was found in 100% and 67.3% of HIV-positive and HIV-negative IDAs, respectively. HIV prevalence was 16.0% in HCV positive IDAs while none of the HCV negative IDAs was positive for HIV. Ethnicity, shared needles or syringes and cotton in the past 3 mo and syphilis infection were associated with HCV/HIV coinfection shown by univariate analysis using chi-square test. Multivariate logistic regression analysis showed that shared needles or syringes in the past 3 mo (Odds ratio=3.121, 95% CI: 1.278-7.617, P<0.05) and syphilis infection (Odds ratio=2.914, 95% CI: 1.327-6.398, P<0.01) were significantly associated with HCV infection. No statistically significant association was found in univariate analysis between sexual behaviors and HCV/HIV coinfection. CONCLUSION: Shared needles and syringes in the past 3 mo and syphilis infection were significantly associated with HCV infection. Further sero-epidemiological prospective cohort studies should be conducted to clarify the impact of syphilis and high risk sexual behaviors on HCV transmission through unprotected sexual intercourse.