Costs and Effectiveness of a syringe distribution and needle exchange programme for HIV prevention in a regional setting

Objective: To estimate the costs and effectiveness of a HIV prevention intervention consisting of distribution of an anti-Aids kit and needle exchange, in operation since 1993 in Navarra, Spain. Methods: Total costs of the programme, namely production, storage and distribution as well as management, are estimated getting a cost figure per sterile syringe distributed. Effectiveness, defined as the number of averted HIV infections among IDUs due to their injecting behaviour, is estimated as a function of the level of coverage of the programme, using a mathematical model. Results: The estimated number of averted HIV infections ranged from 7.59 (in 1995) to 1.23 (in 2000). Yearly incremental cost-effectiveness ratios (ICER) ranged from 8.331 (in 1994) to 44.287 (in 2000) euro per HIV infection averted. With estimated health care costs of treatment of an HIV infection of 99.371 euro, the programme has been cost saving along the whole period considered. One way sensitivity analysis for 5 uncertain parameters was performed. These were the number of active IDUs in the region, number of annual injections among IDUs with non sterile syringes, percentage of lost and unused syringes of the total provided, probability of HIV infection due to injecting behaviour, and life expectancy of HIV+ persons. The results confirm our findings. We conclude the programme has been cost saving from the health care system perspective.