Geographical variations in the prevalence of HIV infection among drug users receiving ambulatory treatment in Spain.

To identify the factors responsible for the regional differences in HIV-positive serostatus among drug users in Spain receiving outpatient treatment, the 17 autonomous regions into which Spain is divided were classified as high (mean 52%) or low prevalence groups (mean 34%) depending on the prevalence of seropositivity. In regions where the prevalence of positive serostatus was high, unemployment was more markedly associated with HIV infection than in low prevalence regions, while other potential risk factors yielded the same strength of association. Even so, adjustment for all the factors only accounted for 13% of the total difference in HIV+ prevalence between regions. The current distribution of risk factors among the two groups of autonomous regions does not explain these differences. [ABSTRACT FROM AUTHOR]