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Motivated by a study exploring spatiotemporal trends in emergency department use, we develop a class of two-part hurdle models for the analysis of zero-inflated areal count data. The models consist of two components-one for the probability of any emergency department use and one for the number of emergency department visits given use. Through a hierarchical structure, the models incorporate both patient- and region-level predictors, as well as spatially and temporally correlated random effects for each model component. The random effects are assigned multivariate conditionally autoregressive priors, which induce dependence between the components and provide spatial and temporal smoothing across adjacent spatial units and time periods, resulting in improved inferences. To accommodate potential overdispersion, we consider a range of parametric specifications for the positive counts, including truncated negative binomial and generalized Poisson distributions. We adopt a Bayesian inferential approach, and posterior computation is handled conveniently within standard Bayesian software. Our results indicate that the negative binomial and generalized Poisson hurdle models vastly outperform the Poisson hurdle model, demonstrating that overdispersed hurdle models provide a useful approach to analyzing zero-inflated spatiotemporal data. [ABSTRACT FROM AUTHOR]

Objectives. We examined HIV diagnosis rates and disease progression among men who have sex with men (MSM) according to race/ethnicity and age. Methods. Using data obtained from the national HIV/AIDS surveillance system, we examined trends in HIV diagnosis rates for 2001 through 2004 using Poisson regression. We used a standardized Kaplan-Meier method to determine differences in time of progression from HIV to AIDS and AIDS survival. Results. HIV diagnosis rates were higher for Black and Hispanic than for White MSM, but trends within age groups from 2001 to 2004 did not differ by race/ethnicity. Diagnosis rates increased among MSM aged 13 to 19 years (14% per year), 20 to 24 years (13%), 25 to 29 years, and 40 to 54 years <3%-6%; PS.01 for each). The percentage of MSM who did not have AIDS 3 years after HIV diagnosis was lower among Black (66.8%; 95% confidence interval [Cl]=66.1,67.4) and Hispanic (68.1%; 95% Cl = 67.5, 68.8} than among White MSM (74.7%; 95% Cl=74.2,75.1). Three-year survival after AIDS diagnosis was lower for Black than for White or Hispanic MSM. Conclusions. HIV prevention efforts should target young and middle-aged MSM and must offer early diagnosis and treatment for all MSM. (Am J Public Health. 2007:97:1060-1066. doi:10.2105/AJPH.2006.087551) [ABSTRACT FROM AUTHOR]

Purpose: The aim of the study is to determine factors associated with disease progression after human immunodeficiency virus (HIV) infection diagnosis. Methods: We applied generalized linear models with Poisson errors to obtain adjusted relative excess risk for death for persons diagnosed with acquired immunodeficiency syndrome (AIDS) or HIV infection (with or without concurrent AIDS) during 1996 to 2001. We examined differences in time between HIV diagnosis and AIDS by using standardized Kaplan-Meier survival methods. Results: Relative excess risk for death within 3 years after AIDS diagnosis was significantly greater for non-Hispanic blacks (1.15; 95% confidence interval [CI], 1.12–1.18), American Indians (1.33; 95% CI, 1.16–1.52), and Hispanics (1.16; 95% CI, 1.13–1.20) compared with whites. Risk for death also was greater among injection drug users (men, 1.50; 95% CI, 1.46–1.54; women, 1.57; 95% CI, 1.51–1.62) compared with men who have sex with men and among those diagnosed at older ages compared with younger persons. Similar disparities between groups in risk for death were observed from HIV diagnosis. Risk for progression from HIV to AIDS was greater for nonwhites, men, and older persons compared with whites, women, and younger persons, respectively. Conclusions: Interventions should target those at excess risk for death or morbidity to ensure access to quality care and adherence to treatment to slow disease progression. [Copyright &y& Elsevier]

Purpose: To estimate relative survival (RS) after human immunodeficiency virus (HIV) diagnosis, by race/ethnicity and county-level socioeconomic status (SES)., Methods: We estimated 5-year RS by age, race/ethnicity, transmission category, sex, diagnosis year, CD4 count, and by county-level SES variables from the U.S. Census. Data, from the national HIV/AIDS Reporting System, were for HIV-infected persons ages > or =13 years (diagnosis during 1996-2003 and follow-up through 2005). We calculated RS proportions by using a maximum likelihood algorithm and modeled the relative risk of excess death (RR) using generalized linear models, with poverty as a random effect., Results: For men, RS was worse in counties with larger proportions of people living below the 2000 U.S. poverty level (87.7% for poverty of > or =20% vs. 90.1% for poverty of <5.0%) and where unemployment was greater (87.8% where unemployment > 7.1% vs. 90.5% where unemployment < 4.0%). The effects of county-level SES on RS of women were similar. In multilevel multivariate models, RR for men and women within 5 years after an HIV diagnosis was significantly worse in counties where 10.0-19.9% (compared with <5.0%) lived below the poverty level (RR = 1.3 [95% CI 1.2-1.5] and RR = 1.8 [95% CI 1.4-2.2], respectively)., Conclusions: RS was worse in lower SES areas. To help address the impact of county-level SES, resources for HIV testing, care, and proven economic interventions should be directed to areas with concentrations of economically disadvantaged people.

Objective: To assess the degree of duplicate reporting in the US HIV/AIDS surveillance system as compared with a performance standard of <5%, and to assess the effect of duplicate removal on epidemiologic trends., Methods: Multistate evaluation of HIV/AIDS case surveillance. Potential duplicate HIV or AIDS case reports in the national surveillance system matched on Soundex, birth date, and sex were assessed for duplication by state and territorial health departments., Results: Of the 990,175 cases of HIV infection and AIDS in the surveillance system on December 31, 2001, 44,945 (4.5%) were identified as duplicate reports. The duplication rate was higher for HIV cases (8.2%) than for AIDS cases (3.8%). The median of 322 duplicate AIDS reports per area (range: 1 to 3947) represented a median of 5% of all AIDS reports per area (range: 1% to 11%). The median of 369 duplicate HIV reports per area (range: 1 to 1247) represented a median of 11% of all HIV reports per area (range: 1% to 30%)., Discussion: The overall duplication rate was within acceptable limits in the national HIV/AIDS surveillance system but did not meet the standard for HIV cases. Ongoing centrally coordinated efforts are necessary to minimize duplicate reporting in the future.

Objectives: In the United States a growing proportion of cases of heterosexually acquired HIV infections occur in women and in persons of color. We analyzed the association between race/ethnicity, whether diagnoses of HIV infection and AIDS were made concurrently, and the survival after diagnosis of heterosexually acquired AIDS., Methods: We used data from 29 states that report confidential name-based HIV/AIDS cases to the Centers for Disease Control and Prevention to calculate estimated annual percentage change in the number of actual diagnoses and analyzed the association between race/ethnicity and concurrent diagnoses of HIV and AIDS. We adjusted for reporting delays and absence of information about HIV risk factors., Results: During 1999 to 2004, diagnoses of heterosexually acquired HIV were made for 52 569 persons in 29 states; 33 554 (64%) were women. Among men and women, 38 470 (73%) were non-Hispanic Black; 7761 (15%), non-Hispanic White; and 5383 (10%), Hispanic. The number of persons with heterosexually acquired HIV significantly increased: 6.1% among Hispanic men (95% confidence interval=2.7, 9.7) and 4.5% among Hispanic women (95% confidence interval=1.8, 7.3). The number significantly decreased (-2.9%) among non-Hispanic Black men. Concurrent HIV and AIDS diagnoses were slightly more common for non-Hispanic Whites (23%) and Hispanics (23%) than for non-Hispanic Blacks (20%)., Conclusions: To decrease the incidence of heterosexually acquired HIV infections, prevention and education programs should target all persons at risk, especially women, non-Hispanic Blacks, and Hispanics.