Tirando Esquina: Methodological Considerations in the Implementation of a Projection Mapping Intervention for Crack Users in Mexico City

Background and Purpose: Recent evidence has identified an increased prevalence of crack use and sexual risk practices among poor urban populations in Mexico City. The largest increases are occurring in neighborhoods characterized by high population density, poverty, unemployment and criminal activities. Although HIV testing and treatment services are available at government-funded facilities, those most at-risk for infection are blocked from seeking diagnosis and treatment services by a range of barriers. Tirando Esquina – Interviniendo Muros de Salud (TE – IMS) is a bi-national effort between the U.S. and Mexico aimed to promote HIV health seeking behaviors among active crack smoking men and women living in hard to access contexts. The present study reports on the design, implementation and methodological consideration of the intervention program.

Methods Using projection mapping technology, TE–IMS intervention was designed to provide a “behavioral nudge” by implementing a public health education campaign to promote healthful behavior, combined with the distribution of related materials focused on education, awareness and harm reduction to facilitate the adoption and maintenance of health promoting behaviors. Projection mapping is a form of technology that connects with audiences on the street by using any structure or object in the location as a canvas to project desired content. During the course of one year, staff gained access, trust and rapport with crack users in three colonias, established linkages with key community members and recruited a sample of 58 currents users for a repeated measure, one group pretest-posttest design.

Results A total of 52 male and 6 female crack users completed baseline interviews. Ages ranged from 17 to 69 with a mean age of 39.7 years. All participants were crack users: 19 reported daily use (33%) with 40 participants reporting polydrug use in the past month (70%). Just under half were never in drug treatment (47%) and 52% have been incarcerated at least once. Crack use decreased following the Tirando Esquina intervention. In the baseline, all 58 respondents (100%) used crack, but this decreased to 30 respondents (88%) of the post-test sample (N=35). In terms of frequency of crack use, analysis showed that the decrease amongst respondents was significant, X2 (1, n=30)=13.93, p<.05. Respondents were asked about which of the messages they found to be the most impactful and 12 respondents (46%) stated that the messages regarding the risks of crack use were the most impactful. Other common answers were the information given about HIV and other STIs (27%) as well as the general support (19%) offered by the program.

Conclusion and Implications Findings suggest that these specific methodological considerations, including new and innovative technology promoting increasing knowledge and awareness in geographically isolated neighborhoods, can disrupt crack users lives and incite healthy behaviors contributing to a decrease in harmful practices and increasing health seeking HIV services. Utilizing measures that target communities can assist in promoting harm reduction throughout areas, and can be especially effective in targeting geographically isolated areas.