Original article |
The cost-effectiveness of a competitive voucher scheme to reduce sexually transmitted infections in high-risk groups in Nicaragua
1 Infectious Disease Epidemiology Unit, London School of Hygiene and Tropical Medicine, London, UK and 2 Instituto Centroamericano de la Salud, Managua, Nicaragua
Correspondence: Josephine Borghi, Infectious Disease Epidemiology Unit, London School of Hygiene and Tropical Medicine, Keppel St, London, WC1E 7HT, UK. Tel: +44 (0)20 7612 7887; Fax: +44 (0)20 7637 5391; E-mail: Jo.Borghi{at}lshtm.ac.uk
Current evidence suggests that sexually transmitted infection (STI) interventions can be an effective means of human immunodeficiency virus (HIV) prevention in populations at an early stage of the epidemic. However, evidence as to their cost-effectiveness when targeted at high-risk groups is lacking. This paper assesses the cost-effectiveness of a competitive voucher scheme in Managua, Nicaragua aimed at high-risk groups, who could redeem the vouchers in exchange for free STI testing and treatment, health education and condoms, compared with the status quo (no scheme). A provider perspective was adopted, defined as: the voucher agency and health care providers from the public, NGO and private sectors. The cost of the voucher scheme was estimated for a 1-year period (1999) from project accounts using the ingredients approach. Outcomes were monitored as part of ongoing project evaluation. Costs and outcomes in the absence of the scheme were modelled using project baseline data and reports, and relevant literature.
The annual cost of providing comprehensive STI services through vouchers was US$62 495, compared with an estimated US$17 112 for regular service provision in the absence of the scheme. 4815 vouchers were distributed by the voucher scheme, 1543 patients were tested for STIs and 528 STIs were effectively cured in this period. In the absence of the scheme, only an estimated 85 cases would have been cured from 1396 consultations. The average cost of the voucher scheme per patient treated was US$41 and US$118 per STI effectively cured, compared with US$12 per patient treated and US$200 per STI cured in its absence. The incremental cost of curing an STI through the voucher scheme, compared with the status quo, was US$103. A voucher scheme offers an effective and efficient means of targeting and effectively curing STIs in high-risk groups, as well as encouraging quality care practices.
Key Words: cost-effectiveness, vouchers, sexually transmitted infections, sex workers
1Two cost-effectiveness analyses of US-based STI treatment programmes for juvenile and county jail detainees were identified (Silberstein et al. 2000; Mrus et al. 2003).
2One sex worker presented herself as a housewife and another as a sex worker.
3Competition refers to the fact that in the described programme there is competition between service providers, as opposed to programmes where the voucher is redeemable at a single service provider. Competition substantially increases the potential to produce efficiency and quality improvements in the health care services delivered. Competitive voucher schemes are one form of demand-side financing where purchasing power is given to the individuals and money follows the patient (Gorter et al. 2004a; Sandiford et al. 2004).
4Nicaragua has high levels of resistance of gonorrhoea for both antibiotics.
5Since 2003, the scheme has been scaled-up to other departments of Nicaragua and to men who have sex with men.
6There were different strata of sex worker, ranging from female glue-sniffers and market-based workers at the lower end of the pay scale to night-club-based at the higher end.
7This is based on the assumptions that all chlamydia and gonorrhoea cases attending the initial gynaecological consultation will be effectively cured by a single dose of azithromycin; and that syphilis and trichomoniasis cases are only effectively cured if they return for, and receive treatment during, the follow-up consultation.
8Source: [http://www.peacecorps.org/countries/nic/index.cfm], accessed on 2 July 2003.