Characteristics of Overdose Cases in Tijuana, Mexico: New Approaches for Identifying Drug Users At Risk for HIV

Introduction: Overdose (OD) is a significant cause of morbidity and mortality in drug users and in people living with HIV; in some countries it is the leading cause of death in these populations. The US-Mexico border city of Tijuana is known for its central “red light” district characterized by sex work and drug tourism. However, little is known about the epidemiology of drug use outside of this area. While incident HIV infections are usually not visible, drug ODs often result in an ambulance response that can be documented. Therefore, we used ambulance response records to identify OD cases in Tijuana from 03/12 to 03/13 in an effort to locate areas where people are at risk for both OD and HIV and better target ongoing prevention programs such as OD interventions that help engage out-of-treatment drug users with a number of public health resources, including HIV prevention services.

Methods: We conducted a secondary analysis using existing data from the Mexican Red Cross in Tijuana, Mexico. Two clinicians reviewed 4 months of ambulance records and used clinical diagnostic procedures to extract: OD cases (defined as altered mental state, respiratory depression or death as a result of the administration of a substance), clinical treatment, drug type, demographic and geographic information. We examined the association between SES (determined by the address of the patient and cross referenced with the national census data) and OD prevalence, clinical treatment and outcome. We geocoded the address of the ODs using Google maps API and plotted the incidents on a map of Tijuana using QGIS, and assessed their proximity to the city’s “red district” and their distribution by drug type.

 Results: In the preliminary 4 months of data (03/12-07/12), we identified 89 OD cases. The majority was male (n=64; 72%) with a mean age of 34 (range: 12 to 57). Most occurred in the patient’s home (36%). Data about types of drugs involved were available in 67% of the cases (n=60). Benzodiazepines (n=22; 25%) and heroin (n=21; 24%) were the most commonly identified drugs. As for outcome, 76% (n=68) were transported to a hospital, 92% (n=82) of the patients lived and 8% (N=7) died at the scene. Only 29% of the cases were located in the “red light” district; the remaining occurred scattered throughout the city. Significantly, 7 patients were of United States origin, 5 of those were found in a “red light” hotel and 2 were found dead on the scene when the ambulance arrived.

 Conclusions: A significant proportion of ODs were located outside the expected “red light” district, but scarcely any prevention programs exist to target these higher SES communities. Our findings can be used to identify unique geographical areas of the community with individuals at risk for HIV/OD.