HIV incidence among repeat HIV testers at a county hospital, San Francisco, California, USA

OBJECTIVES: To estimate HIV incidence, characterize correlates of HIV seroconversion, and monitor temporal trends in HIV transmission among patients repeatedly tested for HIV by a county hospital in San Francisco. DESIGN: Retrospective longitudinal study. METHODS: HIV incidence was retrospectively calculated among persons voluntarily tested for HIV antibody more than once at San Francisco's county hospital or one of its affiliated satellite community clinics between 1993 and 1999. Linkage of HIV test results in computerized databases identified "seroconverters" as individuals who had a negative antibody test followed by a positive test. The interval between tests was used as the person-time at risk. Cox proportional hazards analysis identified correlates of HIV seroconversion. RESULTS: A total of 84 HIV seroconversions were identified among 2893 eligible patients repeatedly tested for HIV antibody over a cumulative 5860 person-years (PYs) (incidence of 1.4 per 100 PYs, 95% confidence interval [CI]: 1.2-1.7). The majority of seroconversions (71 [84.5%]) were among injection drug users (IDUs) (incidence of 2.0 per 100 PYs, CI: 1.6-2.4). HIV incidence was highest among men who have sex with men (MSM) who were also IDUs (incidence of 3.8 per 100 PYs, CI: 2.7-5.1) and lowest among non-IDUs, heterosexual men, and non-IDU women (incidence of 0.3 per 100 PYs, CI: 0.1-0.6). In multivariate analysis, correlates of HIV seroconversion were age 25 to 29 years (hazard ratio [HR] = 3.9, CI: 2.4-6.3), MSM (HR = 2.9, CI: 1.9-4.4), and IDU (HR = 3.2, CI: 1.8-5.8). Overall, no temporal trend in annual HIV incidence was noted during the study period; however, HIV incidence among MSM IDUs increased from 2.9 per 100 PYs in 1996 to 4.7 per 100 PYs in 1998. CONCLUSIONS: The rate of seroconversion in this hospital and affiliated clinic population is unexpectedly high. Moreover, HIV transmission among IDU patients has not decreased over the last several years. The San Francisco county hospital provides a high-risk sentinel population to monitor emerging trends in HIV transmission, especially among IDUs, and presents multiple opportunities for prevention interventions, because these patients are being seen repeatedly by clinicians.     

Absolute CD4 vs. CD4 percentage for predicting the risk of opportunistic illness in HIV infection

Current guidelines recommend consideration of CD4 cell percentage as well as CD4 cell count in therapeutic decisions. The relative value of CD4 cell count compared with CD4 cell percentage in predicting risk of AIDS-defining illnesses (ADIs) in the post-HAART (highly active antiretroviral therapy) era is unknown. Data from an observational clinical cohort of adult HIV-infected patients were used to assess the risk of developing an ADI associated with specific absolute CD4 counts (CD4) and CD4%'s (CD4%) using all CD4-CD4% pairs obtained after January 1996. The incidence of developing an ADI was assessed over a maximum of 6 months after the CD4-CD4% pair was obtained. Using multivariable negative binomial regression, the incidence rate ratio (IRR) for developing an ADI by CD4 and CD4% categories was computed. A total of 15,736 CD4-CD4% pairs from 2185 patients who developed 608 ADIs was analyzed. The IRR for developing an ADI by absolute CD4 was 17.9 (95% CI: 13.2, 24.4) events/100 person-years for <50 cells/mm, 6.2 (95% CI: 4.4, 7.9) for 50-100 cells/mm, and 2.7 (95% CI: 1.9, 4.0) for 100-200 cells/mm, compared with the referent stratum of 200-350 cells/mm. Without adjustment for absolute CD4, the IRR was 14.4 (95% CI: 9.3,22.6) for CD4% <7%, 3.7 (95% CI: 2.4,5.9) for 7-14%, 1.9 (95% CI: 1.1, 3.1) for 15-21%, compared with the referent stratum of >21%. However, in a multivariable analysis adjusting for absolute CD4, CD4%, and other clinical and demographic variables, the absolute CD4 but not the CD4% was associated strongly with developing an ADI. The results suggest that CD4% adds little further predictive information after accounting for the absolute CD4 count for the short-term risk of developing an ADI. The absolute CD4 count is the more important measure of immune status and is preferred over the CD4% for making treatment decisions in HIV-infected adults.     

Continuing HIV transmission among injection drug users in Eastern Central Canada: the SurvUDI Study, 1995 to 2000

OBJECTIVE: To document HIV prevalence/incidence trends from 1995-2000 and associated risk factors among injection drug users (IDUs) in Eastern Central Canada as an indication of harm reduction strategy effectiveness. METHODS: Nonnominal cross-sectional data (one-time participants) and longitudinal data (repeat participants) were collected using convenience sampling. Participants provided informed consent for face-to-face interviews focused on injection drug use and sexual practices during the previous 6 months; oral fluid samples were taken for HIV testing by enzyme immunoassay. Unique encrypted codes for initially HIV-negative repeat participants permitted incidence rate calculations. RESULTS: In all, 6387 IDUs (median age, 31 years; range, 13-67; males, 73.5%) participated on 9724 occasions. HIV prevalence ranged from 4.7% (95% confidence interval [CI], 2.9-6.5) in semiurban areas to 20.1% (95% CI, 17.6-22.7) in Ottawa, Ontario. HIV incidence was 6.0 (95%CI, 4.5-7.6) per 100 person-years (py) in Montréal, Québec, 3.2 (95% CI, 2.2-4.2) per 100 py in Québec City and 7.0 (95% CI, 4.1-9.8) per 100 py in Ottawa/Hull. Reusing other IDUs' needles was reported by 38.4%. In multivariate logistic regression, IDUs injecting for 6 or more years were more likely to be HIV positive, particularly if cocaine was the predominant drug injected. Multivariate Cox regression revealed higher HIV incidence among those who predominantly injected cocaine, reused others' needles, had injected 6 years or more, injected with strangers, or were men reporting commercial sex work. CONCLUSIONS: These results reveal a volatile situation of continuing HIV transmission among IDUs in Eastern Central Canada.     

HIV prevalence and risks among injection and noninjection drug users in northern Thailand: need for comprehensive HIV prevention programs

The authors sought to determine sociodemographic and sexual and drug use risk factors for HIV infection among drug users in northern Thailand adjacent to the Golden Triangle. The authors enrolled patients admitted for inpatient drug detoxification at one treatment center in northern Thailand and studied HIV risks and prevalence using an interviewer-administered questionnaire and serum collection with HIV pretest and posttest counseling. Between February 1, 1999 and January 31, 2000, 1865 patients admitted for opiate and methamphetamine dependence completed study procedures. Overall HIV prevalence was 10.3%: 30.0% among 513 injection drug users (IDUs) and 2.8% among non-IDUs (OR = 14.8, 95% CI: 10.2, 21.6). HIV seroprevalence was 2.4% among exclusive methamphetamine users (98% of whom are non-IDUs) and 3.4% among opium smokers. Injection drug use was the dominant risk factor in multivariate models. Although Thailand is widely recognized as having a successful national response to the heterosexual HIV epidemic, seroprevalence in IDUs remains high. Despite a sharp increase of non-IDUs admitted to the drug treatment center, HIV infection and risks remained high among IDUs in northern Thailand. HIV prevention campaigns need to focus on IDUs and to implement harm reduction strategies to reduce transmission to IDUs and further contain the HIV epidemic in Thailand.     

The incidence of Kaposi sarcoma among injection drug users with AIDS in the United States

Some studies report increased prevalence of human herpesvirus 8 (HHV-8), the causative agent of Kaposi sarcoma (KS), among injection drug users (IDUs), suggesting that HHV-8 may be transmitted through blood-borne or other exposures common in this population. Since an elevated HHV-8 prevalence in IDUs would likely lead to increased KS incidence, KS incidence was studied in IDUs and non-IDU's with AIDS. AIDS-related KS cases were identified using linked US AIDS and cancer registry data for 25,891 women, 47,782 heterosexual men, and 90,616 men who have sex with men (MSM). KS arose in 7099 persons with AIDS. KS incidence was highest for MSM (5.7 per 100 person-years), substantially lower for heterosexual men (0.7 per 100 person-years), and lowest for women (0.4 per 100 person-years). After adjustment for age, race, registry location, and year of AIDS onset, relative risks for KS associated with injection drug use were 1.3 (95% CI, 0.9-1.8) among women, 1.1 (0.7-1.6) among heterosexual men, and 0.9 (0.8-0.9) among MSM. It is concluded that injection drug use was not associated with an increased risk of AIDS-related KS. Thus, these data suggest that IDUs' risk of acquiring HHV-8, through needle sharing or other behaviors related to injection drug use, is low.     

Improving Participation in HIV Clinical Trials: Impact of a Brief Intervention

Abstract

Purpose: To determine if a brief intervention that provides information about AIDS clinical trials to HIV-infected patients at the initiation of primary care increases the participation of women, persons of color, and injection drug users (IDUs) in clinical trials. Method: 196 outpatients beginning HIV primary care at a municipal hospital were followed from September 1994 to April 1996. During the intake assessment, each patient met briefly with a research assistant who described the purpose, role, and availability of clinical trials. Contacts for further information about trials were given to patients who expressed interest. At the end of the 20-month period, enrollment rates of all patients, including women, persons of color, and IDUs, into clinical trials were compared with previously published enrollment rates of patients at the same hospital but prior to the development of this brief intervention. Results: The characteristics of the 196 HIV-infected patients were: 27% women; 47% IDUs; 14% gay/bisexual men; and 76% persons of color. Overall enrollment in AIDS clinical trials was 14.8% during the 20-month follow-up period. There was no significant difference in participation rates between males and females (p = .20), whites and persons of color (p = .71), and IDUs compared with non-IDUs (p = .90), whereas previously published data had shown significantly higher enrollment rates among males, whites, and non-IDUs. Conclusion: Providing all HIV-infected patients with information about the meaning, role, and availability of AIDS clinical trials at the initiation of HIV primary care reduces differences in participation rates by gender, race, and history of drug use.     

Impact of highly active antiretroviral therapy on individual AIDS-defining illness incidence and survival in Australia

OBJECTIVE: To determine the effect of highly active antiretroviral therapy (HAART) on incidence of initial AIDS-defining illnesses (ADIs) and survival after individual ADIs. METHODS: Australian AIDS notification data over the period 1993 to 2000 were examined. Analyses were based on all initial ADIs. To examine the impact of HAART, two periods of AIDS diagnosis were chosen: pre-HAART (1993-1995) and HAART (1996-2000). Comparisons between these two periods included proportion of individual ADIs, median CD4 lymphocyte counts at and survival following AIDS and individual ADIs. Median survival was based on Kaplan-Meier estimates, with examination of factors influencing survival in a Cox proportional hazards model. RESULTS: Over the period 1993 to 2000 in Australia, 5017 initial ADIs were diagnosed among 4351 AIDS cases. At AIDS diagnosis, changes from the pre-HAART (1993-1995) to HAART (1996-2000) periods included an increased proportion of Pneumocystis carinii pneumonia (PCP) (25.9% to 30.4%; p =.001), AIDS dementia complex (5.2% to 6.8%; p = 0.029), non-Hodgkin lymphoma (NHL) (4.4% to 6.3%; p =.005), and tuberculosis (0.5% to 2.7%; p <.0005). Median survival following AIDS increased from 19.6 months for AIDS cases diagnosed in 1993 to 1995 to 39.6 months for AIDS cases diagnosed in 1996 to 2000 (p <.0005). Median survival was stable for NHL (7.5-8.8 months; p =.26), but increased significantly for almost all other ADIs. CONCLUSIONS: An increased proportion of PCP relative to other ADIs suggests an increasing proportion of AIDS patients not receiving specific prophylaxis, presumably because of "late" HIV diagnosis. Survival following almost all ADIs has increased in the era of HAART, although the prognosis after NHL remains extremely poor.     

A prognostic model for HIV seroconversion among injection drug users as a tool for stratification in clinical trials

OBJECTIVE: The main goal of this study was to construct a prognostic model for HIV seroconversion among injection drug users (IDUs) using easy-to-measure risk indicators. DESIGN: Cox proportional hazards regression modeling was used for risk stratification in a heterogeneous population of IDUs with regards to HIV risk-taking behaviors. METHODS: Subjects were recruited in a prospective cohort of IDUs followed between September 1992 and October 2001. A total of 1602 men, seronegative at enrollment with at least 1 follow-up visit, were included in the analyses. Only variables that consistently predict HIV seroconversion in several settings were considered. The final model was used to assign a risk score for each participant. RESULTS: Three risk indicators were included in the risk score to predict HIV seroconversion: unstable housing, average cocaine injections per day, and having shared a syringe with a known HIV-positive partner. Kaplan-Meier survival functions were generated and risk score values stratified in 3 groups. HIV incidence rates per 100 person-years were as follows: 0.91 (95% CI, 0.55-1.52) for the low-risk group, 3.10 (95% CI, 2.49-3.84) for the moderate-risk group, and 7.82 (95% CI, 6.30-9.73) for the high-risk group (log-rank P value < 0.0001). CONCLUSION: If validated in other settings, this risk score may improve the prediction of outcome and allow more accurate stratification in clinical trials.     

Incarceration and risk for HIV infection among injection drug users in Bangkok.

OBJECTIVE: To assess potential multiple relationships between incarceration and HIV infection among injecting drug users (IDUs) in Bangkok. Previous cross-sectional studies have shown strong relationships between incarceration and HIV infection but have not been able to assess potential causal pathways. METHODS: Injection drug users seen at methadone treatment programs in Bangkok were screened during 1995 to 1996 for enrollment into the study. With informed consent, 1,209 seronegative IDUs were enrolled in a cohort study to determine HIV incidence and identify factors associated with incident infections. Follow-up visits were conducted every 4 months, with HIV testing and assessment of risk behaviors. RESULTS: Overall incidence rate was 5.8 per 100 person-years (95% confidence interval [CI], 4.8-6.8) of follow-up. A four-step "injection risk" scale was constructed that included less frequent than daily injection, daily injection, daily injection with reported sharing of injection equipment, and injection while incarcerated. This scale was strongly related to HIV incidence, with incidence approximately doubling for each step in the scale. Incidence rate for follow-up periods that contained drug injection while incarcerated was 35/100 person-years at risk. In multivariate analyses, incarceration was related to incident HIV infection in multiple ways: previous incarceration and recent incarceration without drug injection, and the injection risk scale were all independently predictors of incident HIV infection. CONCLUSIONS: Incarceration is related to incident HIV infection through multiple pathways. Previous incarcerations are likely to serve as markers for unmeasured high-risk behaviors, and it is also highly likely that HIV is transmitted during periods of incarceration. Programs to reduce HIV transmission in jails and prisons, including drug abuse treatment of inmates and programs to reduce the likelihood of incarceration of IDUs, are needed urgently. Given the current diffusion of injecting drug use, of HIV infection among drug injectors, and of the common policy of incarcerating drug users, it is very likely that the problem of HIV transmission in jails and prisons is increasing in many countries throughout the world.     

Epidemiology of HIV Among Injecting and Non-injecting Drug Users: Current Trends and Implications for Interventions

Injecting drug use is a major driver of HIV infections in Eastern Europe, the Commonwealth of Independent States, North Africa, the Middle East, and many parts of Asia and North America. We provide a global overview of the epidemiology of HIV infection among drug users and present current drug use trends that may constitute important epidemic drivers. We describe trends in ethnic disparities among injecting drug using (IDU) populations in the United States, and comment upon how these trends may now be changing. We present examples where HIV infection among non-IDUs who use cocaine, crack, and methamphetamine by other routes of administration is similar to that among IDUs, and discuss potential mechanisms of HIV spread in this overlooked population. Finally, we comment upon the potential implications of these observations for HIV interventions among IDU and non-IDU populations, taking into account different strategies that are needed in settings where HIV and/or injecting drug use has been established, or threatens to emerge.     

Inability to access addiction treatment and risk of HIV infection among injection drug users

It was recently found that 94% of the nearly $500 million allocated annually to Canada's illicit drug strategy has been spent on enforcement-based interventions. As a result, lack of funds for addiction treatment has meant demand for substance abuse treatment among illicit drug users has exceeded availability. This study evaluated whether injection drug users (IDUs) who reported being unable to access addiction treatment were at elevated risk of HIV infection. A prospective analysis was done of factors associated with syringe borrowing by baseline HIV-negative IDUs among participants enrolled in the Vancouver Injecting Drug Users Study (VIDUS). Since serial measures for each individual were available, variables potentially associated with syringe borrowing were evaluated using generalized estimating equations (GEEs) with logit link for binary outcomes. Overall, 1157 HIV-negative IDUs were enrolled into the VIDUS cohort between May 1996 and May 2002. Unsuccessful attempts to access addiction treatment were associated with reporting syringe borrowing during follow-up in both univariate (odds ratio 1.72; 95% CI 1.47-2.00; P<0.001) and in multivariate GEE analyses (adjusted odds ratio 1.29; 95% CI 1.09-1.53; P=0.003). Inability to access addiction treatment was independently associated with syringe borrowing among HIV-negative IDUs at risk for HIV infection. These findings suggest that the limited provision of addiction treatment may result in a major missed opportunity to reduce HIV transmission behavior among IDUs and that the expansion of addiction treatment services has major potential to reduce the substantial human and fiscal costs of HIV infection.     

Changes in AIDS-defining illnesses in a London Clinic, 1987-1998.

OBJECTIVES: To describe the incidence of AIDS-defining illnesses within a single large clinic setting, to describe temporal changes over a 10-year period in the overall incidence and of individual AIDS-defining illnesses and to investigate the impact of HIV treatment regimen on the incidence of AIDS-defining illnesses. SUBJECTS AND METHODS: A person-years analysis was used to determine the incidence of AIDS-defining illnesses according to calendar year and stratification by CD4 lymphocyte count and treatment regimen in 1806 patients from the Royal Free Centre for HIV Medicine with at least one CD4 lymphocyte count and follow-up visit. RESULTS: Prior to 1992, the incidence of all AIDS-defining illnesses was 27.4/100 person-years of follow-up (PYFU; 95% confidence interval [CI], 22.8-32.0) and during 1997 this incidence had dropped to 6.9/100 PYFU (95% CI, 4.7-9.1; p < .0001, test for trend). The decline in incidence over time occurred in esophageal candidiasis, cytomegalovirus disease (including retinitis), Kaposi's sarcoma, lymphoma, wasting syndrome, and Pneumocystis carinii pneumonia (p < .05, test for trend), but there was no evidence of a decline in AIDS dementia or in Mycobacterium avium complex. In 1997, among patients with CD4 lymphocyte counts of < or =200 cells/mm3, the incidence rates for any AIDS-defining illness was 51.1/100 PYFU for patients taking no therapy (95% CI, 27.9-85.7), 34.5 among patients on monotherapy (95% CI, 4.2-124.6), 13.2 among patients taking dual combination therapy (95% CI, 3.6-33.8) and 6.1 among patients taking triple therapy or more complex regimens (95% CI, 0.7-22.0; p < .0001, test for trend). CONCLUSIONS: There was a considerable decline in AIDS-defining illnesses during 1996 and 1997, coinciding with the rapid development of new antiretroviral treatments and combinations of treatment. Further follow-up of large observational cohorts is essential to monitor the incidence of diagnoses less common than we were able to consider, such as tuberculosis, cryptosporidiosis, and cryptococcosis, and also to investigate whether the incidence of disease continues to fall, or whether it starts to rise again, as toxicities, compliance, drug resistance, and long-term side effects begin to appear.     

Low estimates of HIV seroconversions among clients of a drug treatment clinic in San Francisco, 1995 to 1998

We estimated HIV incidence among injection drug users attending a drug treatment clinic in San Francisco from 1995 to 1998 using two methods. An anonymous sequential testing method identified no seroconversions among clients seen more than once during the period (one-sided upper 95% confidence limit 1.02 per 100 person-years). A sensitive/less sensitive immunoassay testing strategy detected no early infections (one-sided upper 95% confidence limit 1.90% per year). Methods were concordant and feasible in the setting. Although detection of no new HIV infections in this population of injection drug users (IDUs) is encouraging, epidemiologic studies among IDUs not in treatment are needed to monitor the HIV epidemic effectively.     

Incidence of, risk factors for, clinical presentation, and 1-year outcomes of infective endocarditis in an urban HIV cohort

BACKGROUND: Previous studies described infective endocarditis (IE) in the era before highly active antiretroviral therapy (HAART); however, IE has not been well studied in the current HAART era. We evaluated the incidence of, risk factors for, clinical presentation, and 1-year outcomes of IE in HIV-infected patients. METHODS: We evaluated all cases of IE diagnosed between 1990 and 2002 in patients followed at the Johns Hopkins Hospital outpatient HIV clinic. To identify factors associated with IE in the current era of HAART, a nested case-control analysis was employed for all initial episodes of IE occurring between 1996 and 2002. Logistic regression analyses were used to assess risk factors for IE and factors associated with 1-year mortality. RESULTS: IE incidence decreased from 20.5 to 6.6 per 1000 person-years (PY) between 1990 and 1995 and 1996 and 2002. The majority of IE cases were male (66%), African American (90%), and injection drug users (IDUs) (85%). In multivariate regression, an increased risk of IE occurred in IDUs (AOR, 8.71), those with CD4 counts <50 cells/mm, and those with HIV-1 RNA >100,000 copies/mL (AOR, 3.88). Common presenting symptoms included fever (62%), chills (31%), and shortness of breath (26%). The most common etiologic organism was Staphylococcus aureus (69%; of these 11 [28%] were methicillin resistant). Within 1 year, 16% had IE recurrence, and 52% died. Age over 40 years was associated with increased mortality. CONCLUSIONS: IE rates have decreased in the current HAART era. IDUs and those with advanced immunosuppression are more likely to develop IE. In addition, there is significant morbidity and 1-year mortality in HIV-infected patients with IE, indicating the need for more aggressive follow-up, especially in those over 40 years of age. Future studies investigating the utility of IE prophylaxis in HIV patients with a history of IE may be warranted.     

Social circumstances of initiation of injection drug use and early shooting gallery attendance: implications for HIV intervention among adolescent and young adult injection drug users

To determine correlates of early shooting gallery (SG) attendance and HIV prevalence and incidence among new injection drug users (IDUs), baseline data from a prospective cohort study of street-recruited IDUs aged 15 to 30 years and injecting < or =5 years were used to identify early high-risk practices and salient social circumstances associated with early SG attendance to help in the design of innovative intervention strategies. Of 226 IDUs, 10.6% were HIV-seropositive, and HIV incidence was 6.6 per 100 person-years (95% CI: 2.2-13.3). Median age was 25 years, and most participants were African American (64%) and female (61%). Using multiple logistic regression, early SG attendees were three times as likely to be HIV-seropositive and twice as likely to be initiated by an older IDU. Early SG attendees were also five times more likely to share injection equipment and over three times more likely to report a high-risk injecting network soon after initiating injection. These data suggest that young new IDUs who attend SGs early tend to be initiated by older high-risk IDUs and to share and inject within a high-risk social setting early on as well. Hence, older IDUs may serve as a bridge group to SGs, transmitting HIV from older to younger IDUs.     

Survival rates in NYC in the era of combination ART

BACKGROUND: Since the advent of combined antiretroviral therapy in 1996, substantial decreases in HIV-related morbidity and mortality have been observed in the United States and other developed countries. To assess the effects on overall survival and for specific AIDS-defining illnesses (ADIs), survival among persons with AIDS (PWAs) in New York City (NYC) before and after the introduction of combination therapy was investigated. METHODS: Survival among 79,878 PWAs diagnosed between 1990 and 1998 and reported through March 2001 was estimated. Cumulative survival at 24 months among PWAs was estimated by actuarial methods, and Cox proportional hazards model adjusted for covariates was used to estimate the relative hazard (RH) of death for specific ADIs over time. RESULTS: Overall cumulative survival at 24 months increased from 43% among PWAs diagnosed during 1990-1995 to 76% for those diagnosed 1996-1998. Improving survival for all ADIs was found among PWAs diagnosed after 1995, but changes for immunoblastic lymphoma, primary lymphoma of the brain, and invasive cervical cancer were only moderate and were statistically (p >.05) insignificant. Burkitt lymphoma, immunoblastic lymphoma, invasive cervical cancer, and primary lymphoma of the brain had the highest RH of death among PWAs diagnosed after 1995. CONCLUSIONS: Substantial improvements in survival after 1995 were found for all PWAs but varied by gender, race, risk, socioeconomic status, and specific ADIs. Consistent with other studies, neoplastic ADIs have shown less improvement than other diseases after 1995. The relatively poor outcome of PWAs with neoplastic diseases requires further investigation.     

HIV incidence among high-risk Puerto Rican drug users: a comparison of East Harlem, New York, and Bayamón, Puerto Rico

Significant differences in HIV-related risk behaviors have been found between Puerto Rican drug users in New York City (NY) and Puerto Rico (PR). An examination of HIV incidence rates and characteristics of seroconverters in each location was undertaken. Baseline and follow-up interviewing and HIV testing were conducted in 1998 to 2002 with seronegative Puerto Rican injection drug users (IDUs) and crack smokers from East Harlem, NY (n = 455) and Bayamón, PR (n = 268). There were a total of 32 seroconverters, 9 in NY and 23 in PR, for seroconversion rates of 0.88/100 person-years at risk (pyr; 95% CI, 0.31-1.45) in NY and 3.37/100 pyr (95% CI, 2.02-4.72) in PR (P < 0.001). In PR, variables significantly related to seroconversion were younger age and using shooting galleries. Being in methadone treatment was protective against seroconversion. In NY, crack use was significantly related to seroconversion. The higher seroconversion rate found in PR indicates a need to enhance HIV prevention efforts, including increasing methadone treatment and access to sterile syringes. The need to address sexual risk behaviors in both locations was also indicated. Resources focusing on reducing HIV transmission in the Caribbean should include efforts to target the drug use-HIV epidemic in PR.     

HIV incidence and factors contributed to retention in a 12-month follow-up study of injection drug users in Sichuan Province, China

HIV-1 seroconversion and subtype were evaluated, and factors associated with cohort retention were analyzed for subjects' baseline sociodemographic and behavioral characteristics in a 12-month follow-up study of injection drug users (IDUs). 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. During the 12-month follow-up period, HIV incidence was 3.17 per 100 person-years (95% confidence interval [CI]: 0.98, 5.37), and all subtypes of 8 HIV-1 seroconversions were CRF_07BC. The retention rate at the 12-month follow-up visit was 70.3% (234 of 333 subjects). In a multiple logistic regression model, ethnicity (OR = 0.60, 95% CI: 0.34, 1.04) and appearing at the 6-month follow-up visit (OR = 9.03, 95% CI: 5.14, 15.89) were independently associated with retention. No drug-using or sexual behaviors were found to be associated with retention. This study confirmed one of drug-trafficking routes in mainland China, from Yunnan to Sichuan and then to Xinjiang. This study also suggested that HIV is spreading rapidly to more geographic areas along drug-trafficking routes in China, and a short-term follow-up rate may predict a long-term retention rate in this IDU cohort.     

HIV seroconversion among public sexually transmitted disease clinic patients: analysis of risks to facilitate early identification

OBJECTIVES: We identified risks for HIV seroconversion among public sexually transmitted disease (STD) clinic patients. DESIGN: This was a retrospective cohort study conducted January 1993 through October 2002 of STD clinic attendees aged > or =12 years in Baltimore, Maryland. METHODS: A negative HIV enzyme immunoassay (EIA) test was required for staggered cohort entry. Observation time was 30 days to 3 years. The outcome for multivariate Poisson regression was HIV seroconversion (positive EIA and/or Western blot test) compared among patients with or without sexual risk behaviors, drug use, an STD diagnosis, and signs and symptoms at an initial HIV test. RESULTS: One hundred twenty-five HIV seroconversions occurred among 10,535 individuals and 13,693 person-years of observation, for an incidence of 0.91 HIV seroconversions per 100 person-years (95% confidence interval [CI]: 0.76 to 1.09). Median time to HIV seroconversion was 1.54 years (95% CI: 1.11 to 1.73). In multivariate analysis, increased HIV seroconversion risk was associated with older age, drug use, a sexual partner with syphilis or HIV, genital ulcers, and gonorrhea. HIV incidence per 100 person-years was 4.86 for subjects with an HIV-positive sexual partner, 3.06 for those with injection drug use, and 2.40 for those with genital ulcers. CONCLUSIONS: We found a high rate of HIV seroconversion among STD clinic patients with specific risks. Algorithms with HIV RNA testing targeted to patients at the highest risk for seroconversion may optimize prevention and resource utilization.