Variations in Sexual Behaviors by Use of Specific Substances Among Vancouver Gay, Bisexual, and Other Men Who Have Sex with Men: An Event-Level Analysis.

Event-level studies measure substance use and sexual behaviors happening during a specific sexual encounter, ensuring that both variables are temporally paired. This study explored the event-level associations between a range of sexual behaviors (masturbation, anal sex, oral sex, rimming, fisting, sex toys, and group sex) and five sexualized substances (poppers, methamphetamine, GHB, ecstasy/MDMA, and ketamine) used during 11,582 sexual events reported by 762 gay, bisexual, and other men who have sex with men (GBMSM) in Vancouver, Canada. Data were obtained from a prospective cohort of GBMSM who self-reported their behaviors via computer-based questionnaires on their last sexual encounter with up to five of their most recent partners in the past six months. These clustered data were analyzed with multivariable generalized linear mixed models. Participants reported popper use in 16.1% of sexual encounters, methamphetamine in 8.6%, gamma-hydroxybutyrate (GHB) in 4.1%, ecstasy/3,4-methylenedioxymethamphetamine (MDMA) in 3.3%, and ketamine in 1.5%. Condomless receptive anal sex (25.0% of events) was associated with increased odds of using poppers, methamphetamine, GHB, and ecstasy/MDMA. Group sex (13.1% of events) and sharing sex toys (2.0% of events) were more likely with the use of all five substances. Receiving money/drugs/goods in exchange for sex (2.5% of events) was associated with increased odds of poppers, methamphetamine, GHB, and ecstasy/MDMA use. GBMSM living with HIV (29.9% of participants) had higher odds of using poppers, methamphetamine, and GHB, but lower odds of using ecstasy/MDMA. In conclusion, these event-level results suggest public health strategies are needed to address the possible negative impacts of sexualized substance use among GBMSM.

[Estimating the 2006 prevalence of HIV by gender and risk groups in Tijuana, Mexico]. / Estimaciones de prevalencia del VIH por género y grupo de riesgo en Tijuana, México: 2006.

OBJECTIVE: Estimate the 2006 HIV prevalence among adults aged 15-49 from the general population and at-risk subgroups in Tijuana, Mexico. METHODS: Demographic data was obtained from the 2005 Mexican census and HIV prevalence data was obtained from reports in the literature. We developed a population-based HIV prevalence model for the overall population and stratified it by gender. Sensitivity analysis consisted of estimating standard errors in the weighted-average point prevalence and calculating partial derivatives of each parameter. RESULTS: HIV prevalence among adults was 0.54% (N = 4347) (range 0.22-0.86% [N = 1750-6944]). This suggests that 0.85% (range 0.39-1.31%) of men and 0.22% (0.04-0.40%) of women could have been HIV-infected in 2006. Men who have sex with men (MSM), followed by female sex workers who are injection drug users (FSW-IDU), FSW-non IDU, female IDU, and male IDU were the most at risk groups of infected individuals. CONCLUSIONS: The number of HIV-infected adults among at-risk subgroups in Tijuana is significant, highlighting the need to design tailored prevention interventions that focus on the specific needs of certain groups. According to our model, as many as 1 in 116 adults could potentially be HIV-infected.

Estimaciones de prevalencia del VIH por género y grupo de riesgo en Tijuana, México: 2006 / Estimating the 2006 prevalence of HIV by gender and risk groups in Tijuana, Mexico

Objetivo: Estimar la prevalencia para 2006 de HIV/sida entre población general de 15 a 49 años de edad y en los grupos de riesgo, en la ciudad de Tijuana, México. Métodos: Se obtuvieron datos demográficos del censo mexicano de 2005 y la prevalencia del VIH, de la literatura. Se construyó un modelo de prevalencia del VIH para la población general y de acuerdo con el género. El análisis de sensibilidad consistió en estimar los errores estándar del promedio-ponderado de la prevalencia del VIH y tomar derivados parciales respecto a cada parámetro. Resultados: La prevalencia del VIH resultó ser de 0.54% (N = 4,347) (rango 0.22-0.86% [N = 1750-6944]). Esto sugiere que 0.85% (rango 0.39-1.31%) de los hombres y 0.22% (rango 0.04-0.40%) de las mujeres podrían ser VIH-positivos. Los hombres que tienen sexo con hombres, las mujeres trabajadoras sexuales usuarias de drogas inyectables (UDI), las mujeres trabajadoras sexuales-no UDI, mujeres- UDI y los hombres-UDI, contribuyeron a las proporciones más elevadas de personas infectadas por el VIH. Conclusiones: El número de adultos VIH-positivos entre subgrupos de riesgo en la población de Tijuana es considerable, lo que denota la necesidad de enfocar las intervenciones de prevención en sus necesidades específicas. El presente modelo estima que hasta uno de cada 116 adultos podría ser VIH-positivo.

OBJECTIVE: Estimate the 2006 HIV prevalence among adults aged 15-49 from the general population and at-risk subgroups in Tijuana, Mexico. METHODS: Demographic data was obtained from the 2005 Mexican census and HIV prevalence data was obtained from reports in the literature. We developed a population-based HIV prevalence model for the overall population and stratified it by gender. Sensitivity analysis consisted of estimating standard errors in the weighted-average point prevalence and calculating partial derivatives of each parameter. RESULTS: HIV prevalence among adults was 0.54% (N = 4347) (range 0.22-0.86% [N = 1750-6944]). This suggests that 0.85% (range 0.39-1.31%) of men and 0.22% (0.04-0.40%) of women could have been HIV-infected in 2006. Men who have sex with men (MSM), followed by female sex workers who are injection drug users (FSW-IDU), FSW-non IDU, female IDU, and male IDU were the most at risk groups of infected individuals. CONCLUSIONS: The number of HIV-infected adults among at-risk subgroups in Tijuana is significant, highlighting the need to design tailored prevention interventions that focus on the specific needs of certain groups. According to our model, as many as 1 in 116 adults could potentially be HIV-infected.

Determinants of treatment access in a population-based cohort of HIV-positive men and women living in Argentina.

OBJECTIVE: To report emerging data on the use of highly active antiretroviral therapy (HAART) in Argentina by assessing patterns of HAART access and late vs early treatment initiation in a population-based cohort of adults infected with HIV type-1. DESIGN: The Prospective Study on the Use and Monitoring of Antiretroviral Therapy (PUMA) is a study of 883 HIV-positive individuals enrolled in the Argentinean drug treatment program. Individuals were 16 years of age and older and were recruited from 10 clinics across Argentina. METHODS: Sociodemographic and clinical characteristics were examined using contingency tables (Pearson chi-square test and Fisher exact test) for categoric variables and Wilcoxon rank-sum test for continuous variables. To analyze time to initiation of HAART we used Kaplan-Meier methods and Cox regression. RESULTS: Patients who initiated HAART were more likely to be older, have an AIDS-defining illness, be an injection drug user (IDU), have a lower median CD4 cell count, have a higher median viral load, and be less likely to be men who have sex with men (MSM). In multivariate analysis, AIDS-defining illness and plasma viral load were significantly associated with time to starting therapy. Patients who received late access were more likely to be diagnosed with AIDS and have higher median plasma viral loads than those receiving early access. CONCLUSION: Our results indicate that despite free availability of treatment, monitoring, and care in Argentina, a significant proportion of men and women are accessing HAART late in the course of HIV disease. Further characterization of the HIV-positive population will allow for a more comprehensive evaluation of the impact of HAART within the Argentinean drug treatment program.

Determinants of Treatment Access in a Population-based Cohort of HIV-positive Men and Women Living in Argentina.

OBJECTIVE: To report emerging data on the use of highly active antiretroviral therapy (HAART) in Argentina by assessing patterns of HAART access and late vs early treatment initiation in a population-based cohort of adults infected with HIV type-1. DESIGN: The Prospective Study on the Use and Monitoring of Antiretroviral Therapy (PUMA) is a study of 883 HIV-positive individuals enrolled in the Argentinean drug treatment program. Individuals were 16 years of age and older and were recruited from 10 clinics across Argentina. METHODS: Sociodemographic and clinical characteristics were examined using contingency tables (Pearson chi-square test and Fisher exact test) for categoric variables and Wilcoxon rank-sum test for continuous variables. To analyze time to initiation of HAART we used Kaplan-Meier methods and Cox regression. RESULTS: Patients who initiated HAART were more likely to be older, have an AIDS-defining illness, be an injection drug user (IDU), have a lower median CD4 cell count, have a higher median viral load, and be less likely to be men who have sex with men (MSM). In multivariate analysis, AIDS-defining illness and plasma viral load were significantly associated with time to starting therapy. Patients who received late access were more likely to be diagnosed with AIDS and have higher median plasma viral loads than those receiving early access. CONCLUSION: Our results indicate that despite free availability of treatment, monitoring, and care in Argentina, a significant proportion of men and women are accessing HAART late in the course of HIV disease. Further characterization of the HIV-positive population will allow for a more comprehensive evaluation of the impact of HAART within the Argentinean drug treatment program.

The first ten years: achievements and challenges of the Brazilian program of universal access to HIV/AIDS comprehensive management and care, 1996-2006.

A review was carried out of papers published between 1996 and 2006, documenting the introduction of highly active anti-retroviral therapy (HAART) in Brazil. Papers indexed in the MEDLINE and SciELO databases were retrieved using different combinations of keywords related to the management and care of AIDS in the post-HAART era: opportunistic diseases and co-infections, adherence to therapy, survival in the pre- and post-HAART eras, adverse events and side-effects, emergence and possible transmission of resistant viral strains, metabolic and cardiovascular disorders, and issues related to access to care and equity. The review documents the dramatic changes in HIV/AIDS disease progression in the post-HAART era, including an increase in survival and quality of life and a pronounced decrease in the episodes of opportunistic diseases. Notwithstanding such major achievements, new challenges have emerged, including slow evolving co-infections (such as hepatitis C, metabolic and cardiovascular disorders), the emergence of viral resistance, with consequences at the individual level (virological failure) and the community level (primary/secondary resistance at the population level), and impacts on the cost of new therapeutic regimens.

The first ten years: achievements and challenges of the Brazilian program of universal access to HIV/AIDS comprehensive management and care, 1996-2006

A review was carried out of papers published between 1996 and 2006, documenting the introduction of highly active anti-retroviral therapy (HAART) in Brazil. Papers indexed in the MEDLINE and SciELO databases were retrieved using different combinations of keywords related to the management and care of AIDS in the post-HAART era: opportunistic diseases and co-infections, adherence to therapy, survival in the pre- and post-HAART eras, adverse events and side-effects, emergence and possible transmission of resistant viral strains, metabolic and cardiovascular disorders, and issues related to access to care and equity. The review documents the dramatic changes in HIV/AIDS disease progression in the post-HAART era, including an increase in survival and quality of life and a pronounced decrease in the episodes of opportunistic diseases. Notwithstanding such major achievements, new challenges have emerged, including slow evolving co-infections (such as hepatitis C, metabolic and cardiovascular disorders), the emergence of viral resistance, with consequences at the individual level (virological failure) and the community level (primary/secondary resistance at the population level), and impacts on the cost of new therapeutic regimens.

Procedeu-se a uma revisão abrangente de artigos publicados entre 1996-2006, período posterior à introdução da terapia anti-retroviral de alta potência (HAART) no Brasil. Foram revisados artigos disponíveis nas bases de dados MEDLINE e SciELO, a partir de combinações de palavras-chave que contemplam os principais temas na área do tratamento e manejo da AIDS na era pós-HAART: doenças oportunistas e co-infecções, aderência à terapia, sobrevida pré e pós-HAART, eventos adversos e efeitos colaterais, emergência e eventual transmissão de cepas virais resistentes e complicações cardiovasculares e metabólicas, além de questões relativas ao acesso e à eqüidade. Em suma, observa-se uma transformação profunda no campo da AIDS no período pós-HAART, com aumento dramático da sobrevida e da qualidade de vida, e redução expressiva dos episódios de doenças oportunistas. Por outro lado, novas questões se colocam, como a relevância das co-infecções de evolução lenta, como a hepatite C, os distúrbios metabólicos e cardiovasculares, e o desafio posto pela emergência de cepas resistentes, com repercussões individuais (falha virológica) e coletivas (resistência primária e secundária em nível da comunidade) e, conseqüente, aumento de custos da terapia.

Estimated numbers of men and women infected with HIV/AIDS in Tijuana, Mexico.

Tijuana, Mexico, just south of San Diego, California, is located by the busiest land border crossing in the world. Although UNAIDS considers Mexico to be a country of "low prevalence, high risk," recent surveillance data among sentinel populations in Tijuana suggests HIV prevalence is increasing. The aim of this study was to estimate the number of men and women aged 15 to 49 years infected with HIV in Tijuana. Gender and age-specific estimates of the Tijuana population were obtained from the 2000 Mexican census. Population and HIV prevalence estimates for at-risk groups were obtained from published reports, community based studies, and data from the Centro Nacional para la Prevención y Control del VIH/SIDA (CENSIDA). Age-specific fertility rates for Mexico were used to derive the number of low and high-risk pregnant women. Numbers of HIV-positive men and women were estimated for each at-risk group and then aggregated. A high growth scenario based on current HIV prevalence and a conservative, low growth estimate were determined. A total of 686,600 men and women in Tijuana were aged 15 to 49 years at the time of the 2000 census. Considering both scenarios, the number of infected persons ranged from 1,803 to 5,472 (HIV prevalence: 0.26 to 0.80%). The majority of these persons were men (>70%). The largest number of infected persons were MSM (N = 1,146 to 3,300) and IDUs (N = 147 to 650). Our data suggest that up to one in every 125 persons aged 15-49 years in Tijuana is HIV-infected. Interventions to reduce ongoing spread of HIV are urgently needed.

Using baseline CD4 cell count and plasma HIV RNA to guide the initiation of highly active antiretroviral therapy.

Conflicting evidence regarding the impact of baseline plasma HIV RNA and CD4 cell count on survival after the initiation of highly active antiretroviral therapy (HAART) in HIV-infected patients has resulted in wide variability in the expert recommendations regarding when to start therapy. Early initiation of HAART may result in avoidable toxicities and premature evolution of resistance, whereas delaying HAART may increase the risk of opportunistic infections and/or preclude a worse virological and clinical response to therapy. While there is widespread consensus that HAART can be delayed to a CD4 cell count of 0.350 x 10(9) cells/L, the range between this threshold and 0.200 x 10(9) cells/L remains controversial. Greater uncertainty surrounds the role of baseline plasma HIV RNA, with some guidelines recommending initiating HAART when this level rises above 55,000 c/mL regardless of baseline CD4 cell count. The following review examines the evidence in support of delaying the initiation of HAART to a CD4 cell count of 0.200 x 10(9) cells/L regardless of plasma HIV RNA levels and outlines supporting data from a Canadian prospective cohort study of antiretroviral naive patients treated with HAART.

Using baseline CD4 cell count and plasma HIV RNA to guide the initiation of highly active antiretroviral therapy

Conflicting evidence regarding the impact of baseline plasma HIV RNA and CD4 cell count on survival after the initiation of highly active antiretroviral therapy (HAART) in HIV-infected patients has resulted in wide variability in the expert recommendations regarding the when to start therapy. Early initiation of HAART may result in avoidable toxicities and premature evolution of resistance, whereas delaying HAART may increase the risk of opportunistic infections and/or preclude a worse virological and clinical response to therapy. While there is widespread consensus that HAART can be delayed to a CD4 cell count of 0.350 x 10 9 cells/L, the range between this threshold and 0.200 x 10 9 cells/L remains controversial. Greater uncertainty surrounds the role of baseline plasma HIV RNA, with some guidelines recommending initiating HAART when this level rises above 55,000 c/mL regardless of baseline CD4 cell count. The following review examines the evidence in support of delaying the initiation of HAART to a CD4 cell count of 0.200 x 10 9 cells/L regardless of plasma HIV RNA levels and outlines supporting data from a Canadian prospective cohort study of antiretroviral naïve patients treated with HAART. KEY WORDS. Plasma viral load. Adherence. Viral load supression. Virologic failure. Survival.

La carga viral plasmática y el nivel de los linfocitos CD4+ en la sangre son marcadores biológicos de alto valor pronóstico, en lo que se refiere a la historia natural de la infección por HIV. Esto ha sido demostrado en forma terminante en pacientes no tratados. El impacto y valor relativo de dichos marcadores en el pronóstico de pacientes que inician terapia antirretroviral no está totalmente aclarado. Esto ha generado opiniones diversas en la literatura médica, especialmente en lo que se refiere a las recomendaciones para el inicio del tratamiento en pacientes asintomáticos. Existe acuerdo general que el inicio del tratamiento se puede demorar hasta que los linfocitos CD4+ están en un nivel de 0.350 x 10 9 cells/L. Nuestros resultados, basados en una cohorte prospectiva canadiense, demuestran que es aceptable demorar el inicio del tratamiento hasta que los linfocitos CD4+ están en un nivel de 0.200 x 10 9 cells/L sin importar el nivel de la carga viral plasmática.