The estimated direct medical cost of sexually transmitted diseases among American youth, 2000

Perspectives on Sexual and Reproductive Health, Jan-Feb, 2004 by Harrell W. Chesson, John M. Blandford, Thomas L. Gift, Guoyu Tao, Kathleen L. Irwin

Certain bacterial and viral STDs can facilitate the transmission of HIV, and HIV costs can be an important component of their cost. (64) Because we included HIV costs as a separate category, however, we did not include them as a cost component for other STDs. Prevention of STDs other than HIV might result in reductions in HIV and its associated costs. For example, a published mathematical model (65) of the effects of STDs on HIV transmission suggests that about 2,100 of the estimated 15,000 new HIV infections among young Americans in 2000 might be attributable to coinfection with syphilis, gonorrhea or chlamydia.

Limitations

These estimated lifetime costs per case are subject to considerable uncertainty and should be viewed as ballpark figures rather than precise calculations. Our estimates depend on the numerous assumptions we made in our analysis. In calculating HPV costs, for example, we assumed that patients with atypical Pap test results would be managed in strict adherence to the Bethesda Guidelines. If management is less rigorous, the expected cost per abnormal Pap result will be lower, though this reduction might be offset in part by increased costs of treating invasive cancer in later years. The estimated total burden of STDs ($6.5 billion) is based on the cost-per-case estimates as well the estimated number of cases of each STD. As with the cost-per-case estimates, the incidence estimates are subject to considerable uncertainty.

The estimated cost per case of HIV (the most costly STD in out analysis) is based on a 1997 study, and the lifetime cost may have changed substantially since then. Nonetheless, the estimate we used is the most current one available, and is widely used in cost-effectiveness evaluations of HIV prevention programs. In addition, the lifetime cost ($199,800) we applied appears to be consistent with a more recent estimate of the annual cost of care for persons with HIV. (66)

As with our estimates for HIV, our cost estimates for other STDs are affected by the limitations of the studies on which our estimates are based. For example, cost estimates used in the decision analyses might be from one clinical setting where costs are not readily applicable to other settings. Drug treatment costs based on wholesale prices might underestimate the actual cost of treatment for some purchasers of these drugs. Furthermore, the cost of STDs can change over time. Although we adjusted existing cost estimates for inflation, such adjustment might not fully capture changes in diagnosis, treatment and management in recent years or future years. Such changes might include broader use of urine-based amplification testing for gonorrhea and chlamydia, new guidelines for cervical neoplasia and cancer screening, HPV DNA testing, new treatments for HIV and trichomoniasis, herpes type-specific serology testing and its potential influence on the proportion of persons with genital herpes who receive treatment, and modification of treatment regimens in the face of changing antimicrobial resistance patterns. (67)