Drug therapies for sexually transmitted diseases. Clinical and economic considerations.

Sexually transmitted diseases (STDs) are common, and result in immense social and economic costs. In some countries they have a major demographic impact. Because many STDs facilitate the transmission of HIV, the consequences of STDs are further increasing. At the same time, this association between STDs and HIV provides one of the ways in which drug therapy should be very cost effective. The perspective taken in this article is a societal one, and broader issues than those directly related to drug costs and benefits are discussed. However, it is the availability of drugs that has the potential to most quickly and most reliably make a major difference to overall health sector and societal costs as they relate to STDs. For those STDs for which curative therapy is available (particularly Neisseria gonorrhoeae, Chlamydia trachomatis, Treponema pallidum, and Trichomonas vaginalis) there have been large decreases in prevalence in many parts of the world. In contrast, those STDs for which curative therapy is not available (particularly HIV, genital herpes and genital human papillomavirus infection) have had stable or increasing prevalence. For these latter infections, each new case increases the overall prevalence. Numerous features of STDs make clinical and economic evaluation difficult. These include the sensitive nature of the topic, the changing epidemiology and drug susceptibility of individual STDs, the fact that a large proportion of those infected are asymptomatic, difficulties in making specific diagnoses, the fact that often consequences are recognised late, sexual re-exposure and reinfection, and inadequate data on which to do clinical and economic evaluations. Furthermore, risk of acquiring an STD roughly correlates inversely with socioeconomic status, and countries or places with the highest rates of STDs may have the least ability to deal effectively with their diagnosis and management. Most of the direct and indirect costs are incurred by women, since they experience the vast majority of the complications of STDs. Many of these only become apparent years later, which makes it very hard to attribute costs and benefits to a specific episode of infection, and to its treatment. The late and indirect costs, plus the costs of prevention, are hard to quantify. That the major burden of STDs is in adolescents and young adults, socioeconomically disadvantaged groups and women has important implications, including for pharmacoeconomic studies.(ABSTRACT TRUNCATED AT 400 WORDS)