Ecological Analyses And The Evaluation Of Needle

International Journal of Drug Policy 14 (2003) 359–360

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Ecological analyses and the evaluation of needle and syringe programmes Waleska Teixeira Caiaffa∗ , Fernando Augusto Proietti Department of Preventive and Social Medicine, School of Medicine, Federal University of Minas Gerais (UFMG), Av. Alfredo Balena 190 10o. andar, MG 30130-100 Belo Horizonte, Brazil Received 1 December 2002; received in revised form 15 March 2003; accepted 2 July 2003

Needle/syringe exchange programmes (NSP), despite some controversies, are recognised as a successful intervention in several countries based on a consistent association reported in a myriad of observational studies. Results from the ecological study done by MacDonald, Law, Kaldor, Hales, and Dore (2003) add an additional piece of evidence about NSP effectiveness in preventing HIV infection jigsaw puzzle. Drawing on an extended data from a previous paper published by Hurley, Jolley, and Kaldor in The Lancet (1997), the study confirmed the findings previously reported showing a meaningful correlation: HIV seroprevalence decreased in cities with NSP and increased in cities that had never introduced NSP. Ecological studies have received a negative press and reputation. For the past 50 years, as compared to the individual level based designs, ecological studies have been considered suspect and inferior. Fortunately, ecological studies are nowadays re-emerging as important analytical tools to better understand the interdependence between healthy related events and habits, modes of life and relationships to their surroundings (Berkman, 2000; Morgenstern, 1998; Susser, 1994). In this context, the paper by MacDonald et al. (2003) is a welcome addition. The public health implications of these findings are striking because it is well known that HIV infection related to injecting drug use is a typical combination of individual behaviour (such as needle/syringe sharing) and contextual factors (for example, drug culture and/or drug market) (Des Jarlais, Courtwright, & Joseph, 1991; Nelson et al., 1998). Recently, cohort studies assessing the impact of NSPs based on self-reported risk behaviours have showed that large scale needle exchange programmes do not lead to an increase in injecting drug use, and that decline in in∗

Corresponding author. E-mail address: [email protected] (W.T. Caiaffa).

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jection seems mainly attributable to ecological factors rather than individual ones (van Ameijden & Coutinho, 2001). In this context, we should reflect about costs and feasibility of cohort studies, especially in developing countries where the rapid spread of HIV infection and increases in IDU populations in many countries call for scaling up of harm reductions strategies. As a consequence, in this scenario, cross sectional data are helpful and timely. Ecological studies looking at trends over time, especially in the context of a possibility of comparison between an existing NSP intervention are well justified, especially since randomised trials of the efficacy of NSP in preventing HIV transmission is considered not ethically acceptable in light of their proven effectiveness (Caiaffa & Bastos, 1998). Finally, what are the implications of these findings? Along with numerous recommendations, this article reinforces the need to pursue an aggressive global approach on harm reduction related to injecting drugs given that they represent a wise global investment strategy, providing both human and fiscal resource benefits and showing that public health investments in vulnerable populations will lead to healthier lives.

References Berkman, L., Kawachi, I. (2000). Social epidemiology. New York: Oxford University Press. Caiaffa, W. T., & Bastos, F. I. (1998). Usuários de droga injetável e infecção pelo HIV: epidemiologia e perspectivas de intervenção. Revista Brasileira de Epidemiologia, 1, 2–16. Des Jarlais, D. C., Courtwright, D. T., & Joseph, H. (1991). The transition from opium smoking to heroin injection in the United States. AIDS & Public Policy Journal, 6(2), 20, 88–90. Hurley, S., Jolley, D. J., & Kaldor, J. M. (1997). Effectiveness of needle and syringe exchange programs for prevention of HIV transmission. Lancet, 349, 1797–1800.

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W.T. Caiaffa, F.A. Proietti / International Journal of Drug Policy 14 (2003) 359–360

MacDonald, M., Law, M., Kaldor, J., Hales, J., Dore, G. (2003). Effectiveness of needle and syringe programmes for preventing HIV transmission. International Journal of Drug Policy, 14, 353–357. Morgenstern, H. (1998). Ecological studies. In K. J. Rothman & S. Greenland (Eds.), Modern epidemiology (2nd ed.). Philadelphia: Lippincott-Raven. Nelson, K. E., Galai, N., Safeian, M., Strathdee, S. A., Celentano, D. D., Vlahov, D. (1998). Temporal trends in the incidence of human

immunodeficiency virus infection and risk behavior among injection drug users in Baltimore, MD, 1988–1998. Susser, M. (1994). The logic in ecological: I. The logic of analysis. American Journal of Public Health, 84, 825–829. van Ameijden, E. J., & Coutinho, R. A. (2001). Large decline in injecting drug use in Amsterdam 1986–1998: Explanatory mechanisms and determinants of injecting transitions. Journal of Epidemiology and Community Health, 55, 356–363.