Spatial analysis of HIV positive injection drug users in San Francisco, 1987 to 2005.

Alexis N Martinez,Andrea Lopez,Scott P Novak,Lee R Mobley,Alex H Kral,Jennifer Lorvick

doi:10.3390/ijerph110403937

Abstract

Spatial analyses of HIV/AIDS related outcomes are growing in popularity as a tool to understand geographic changes in the epidemic and inform the effectiveness of community-based prevention and treatment programs. The Urban Health Study was a serial, cross-sectional epidemiological study of injection drug users (IDUs) in San Francisco between 1987 and 2005 (N = 29,914). HIV testing was conducted for every participant. Participant residence was geocoded to the level of the United States Census tract for every observation in dataset. Local indicator of spatial autocorrelation (LISA) tests were used to identify univariate and bivariate Census tract clusters of HIV positive IDUs in two time periods. We further compared three tract level characteristics (% poverty, % African Americans, and % unemployment) across areas of clustered and non-clustered tracts. We identified significant spatial clustering of high numbers of HIV positive IDUs in the early period (1987–1995) and late period (1996–2005). We found significant bivariate clusters of Census tracts where HIV positive IDUs and tract level poverty were above average compared to the surrounding areas. Our data suggest that poverty, rather than race, was an important neighborhood characteristic associated with the spatial distribution of HIV in SF and its spatial diffusion over time.

Highlights

Two decades of intensive community-based, local HIV prevention efforts have shaped the trajectory of the HIV/AIDS epidemic among injection drug users (IDUs) in San Francisco.[1,2,3,4,5,6].Prior to the widespread availability of sterile syringes in the late 1980s, HIV incidence among IDUs inSan Francisco peaked in 1987 at a rate of 2.7% [7]
Using the bivariate Local indicator of spatial autocorrelation (LISA) analysis, we found that new areas of HIV clustering appeared in the late period in the Bayview-Hunters Point, a historically African American and geographically isolated area in the southeastern part of
Our data suggests that socioeconomic status, rather than being African American, was an important neighborhood characteristic associated with the spatial distribution of HIV in San Francisco during both study periods, and its spatial diffusion over time

Summary

Introduction

Two decades of intensive community-based, local HIV prevention efforts have shaped the trajectory of the HIV/AIDS epidemic among injection drug users (IDUs) in San Francisco.[1,2,3,4,5,6].Prior to the widespread availability of sterile syringes in the late 1980s, HIV incidence among IDUs inSan Francisco peaked in 1987 at a rate of 2.7% [7]. A growing body of international research is focused on linking behavior with place and utilizing spatial analytic tools to examine salient issues relevant to HIV prevention [14,15], which include placement of HIV service providers in large urban cities, improper disposal of previously used syringes [16,17,18], and identification of geographic HIV-related risk hotspots [19,20,21,22,23] These types of spatial analyses, which involve studying the distribution of HIV-related outcomes at the geographic level rather than the individual level, have the potential to offer new insights for HIV-related public health policy and prevention programs

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Conclusion