Differentiating geographic patterns of human immunodeficiency virus (HIV) infection with different risk factors in northern Taiwan: 1997–2008

Human immunodeficiency virus (HIV) can be transmitted through sexual activity or needle-sharing. It remains unclear whether geographic patterns of HIV-infected patients with different risk factors can be differentiated using geographic information systems (GIS) and spatial statistical methods. This study examined whether three types of HIV high-risk behaviors, (1) men who have unprotected sex with men (MSM; homosexuals or bisexuals); (2) heterosexuals who have unprotected sex; and (3) heroin/morphine intravenous drug users (IDUs) who share needles or syringes, can be identified in the geospatial dimension. We used GIS and spatial statistical methods to analyze spatial relationships and identify geographic clusters of HIV-infected subjects with different risk behaviors, who were evaluated at the National Taiwan University Hospital during 1997–2008. Our significant findings indicated that the spatial patterns of different HIV risk behaviors significantly differed in both local clustering patterns and global geographic distribution. We demonstrated that GIS and spatial statistical methods can be used to differentiate the geographic patterns of HIV-infected patients with different risk factors. This study provides information valuable for the targeted delivery of HIV prevention programs to people with high-risk behaviors.

Research highlights
► HIV epidemics with different risk factors (sexual activity and needle-sharing) in Taiwan have different geographic patterns.
► There is significant spatial dependency of HIV-infected patients for the MSM and heterosexual groups.
► This study provides information valuable for the targeted delivery of HIV prevention programs to people with high-risk behaviors.