Determinants and prevalence of late HIV testing in Tijuana, Mexico.

Timely diagnosis of HIV is essential to improve survival rates and reduce transmission of the virus. Insufficient progress has been made in effecting earlier HIV diagnoses. The Mexican border city of Tijuana has one of the highest AIDS incidence and mortality rates in all of Mexico. This study examined the prevalence and potential correlates of late HIV testing in Tijuana, Mexico. Late testers were defined as participants who had at least one of: (1) an AIDS-defining illness within 1 year of first positive HIV test; (2) a date of AIDS diagnosis within 1 year of first positive HIV test; or (3) an initial CD4 cell count below 200 cells per microliter within 1 year of first positive HIV test. Medical charts of 670 HIV-positive patients from two HIV/AIDS public clinics in Tijuana were reviewed and abstracted; 362 of these patients were interviewed using a cross-sectional survey. Using multivariate logistic regression, we explored potential correlates of late HIV testing based on the Behavioral Ecological Model. From 342 participants for whom late testing could be determined, the prevalence of late testing was 43.2%. Multivariate logistic regression results (n = 275) revealed five significant correlates of late testing: "I preferred not to know I had HIV" (adjusted odds ratio [AOR] = 2.78, 1.46-5.31); clinic (AOR = 1.90, 1.06-3.41); exposure to peers engaging in high-risk sexual behavior (AOR = 1.14, 1.02-1.27); stigma regarding HIV-infected individuals (AOR = 0.65, 0.47-0.92); and stigma regarding HIV testing (AOR = 0.66, 0.45-0.97). These findings may inform the design of interventions to increase timely HIV testing and help reduce HIV transmission in the community at large.