[Multi-centre study of the prevalence of infection from HIV and associated factors in Spanish prisons]

To determine the prevalence and associated factors of HIV infection amongst inmates in Spain.

Observational and transversal study (June 2008). For 62,000 inmates an "n" of 364 was determined (5% variability, error correction α 5% and 10% missing). 18 prisons were randomly selected and 21 inmates/prison. Frequency measurement: prevalence. Magnitude of the association: odds ratio of prevalence (ORP) with 95%. Statistical significance p<0.05.

371 prisoners were studied (91.6% male, 66.9% ≤ 40 years, 60.6% Spanish, 23.5% IDU and 71.2% incarcerated <5 years). HIV prevalence was 10.8% (CI: 7.5 to 14). 85% were co-infected with HCV, 12.5% with HBV and HCV and 63.2% with M. tuberculosis. This represents a proportion to the prison population of 9.2%, 1.3% and 6.7% respectively. HIV infection was associated with: a) > 40 years (p <0.01), b) imprisoned> 5 years (p <0.001), c) non-Arab (p <0.01), d) Spanish nationality (p <0.001), e) IDUs (p <0.001), f) co-infected with HCV (p <0.001), and g) co-infected with HBV (p <0.001]. Multivariate analysis confirmed the association: a) ≥ 40 years [OR = 2.66 (CI : 1.16-6.07), b) IDU [OR = 28.08 (IC-9.61-81.99), c) infected with HCV [OR = 6.96 (CI :1.90-25.39)], and d) infected with HBV [OR = 13.52 (CI = 1.76-103.82).

The prevalence of HIV infection among prisoners in Spain is 10.8%. Those that are infected are usually IDUs and over 40 years. 85% are co-infected with HCV and 12.5% with HBV and HCV.