HIV Infections and Associated Costs Attributable to Syphilis Coinfection Among African Americans
July 3, 2003
African Americans suffer disproportionate morbidity and mortality from a variety of preventable and treatable health conditions, including cancer, heart disease, and stroke. With regard to HIV/AIDS, African Americans have higher rates of incidence, prevalence, and mortality than any other racial or ethnic group in the United States.
African Americans are also disproportionately affected by other STDs, including syphilis. The 4,231 new cases of primary and secondary syphilis among African Americans reported in 2000 represent more than 70 percent of all such cases. The rate of primary and secondary syphilis among African Americans (12.8 per 100,000) in 2000 was more than 20 times greater than the rate among non-Hispanic whites. Addressing this racial disparity in syphilis is one of the primary goals of the national campaign to eliminate syphilis that was begun October 1999.
Syphilis elimination efforts also might have an impact on HIV incidence rates. Ulcerative STDs such as syphilis can increase HIV infectiousness and susceptibility through a variety of biological processes, such as disruption of epithelial and mucosal barriers to infection. In the current article, the authors estimated the number of HIV cases, and associated costs, attributable to the facilitative effects of infectious syphilis on HIV transmission and acquisition among African Americans. These syphilis-attributable HIV cases represent a potential reduction in HIV incidence among African Americans that could be achieved through syphilis prevention efforts.
The authors adapted a simplified model of the effect of infectious syphilis on HIV transmission to estimate the number of new HIV cases among African Americans attributable to syphilis in 2000. If syphilis is to facilitate HIV transmission from one sex partner to another, the partners must initially be of discordant HIV status, and at least one of the partners must have infectious syphilis. Therefore, the first step in the model was to estimate the number of HIV-discordant partnerships in which infectious syphilis was present. The authors multiplied the estimated number of partnerships by the estimated probability that a syphilis-attributable HIV transmission would occur in such partnerships to arrive at an estimate of the number of new HIV cases attributable to syphilis.
Under base case assumptions, the authors estimated that about 545 new cases of HIV among African Americans in 2000 could be attributed to the facilitative effects of infectious syphilis on HIV transmission. These 545 cases represent about 3 percent to 5 percent of all new HIV cases among African Americans in 2000, assuming that there are 11,200 to 21,600 new HIV infections among African Americans each year. The authors estimated the future treatment costs of these 545 syphilis-attributable HIV cases among African Americans to be approximately $113 million (at $207,000 per case), with a range of $68 million ($125,000 per case) to $150 million ($275,000 per case).
In comparison, nationwide syphilis elimination efforts will require an estimated $60 million annually in federal, state and local funds. These program costs are considerably less than the base case estimate of the syphilis-attributable HIV treatment costs that could be averted through syphilis prevention. In addition, syphilis prevention can avert substantial syphilis treatment costs, such as those associated with congenital syphilis and related complications.
"A successful national syphilis elimination program could reduce HIV incidence among African Americans by 3 percent to 5 percent and could avert as much as $113 million or more annually in lifetime HIV-related medical care costs," the authors concluded. "Because our analysis did not consider secondary transmission of HIV or the potential reduction in risky sexual behaviors that might result from syphilis prevention activities, the potential impact of syphilis prevention on HIV incidence could be even more substantial than we estimated."
American Journal of Public Health
06.03; Vol. 93; No. 6: P. 943-948; Harrell W. Chesson, Ph.D.; Steven D. Pinkerton, Ph.D.; Richard Voigt, M.A.; George W. Counts, M.D.
This article was provided by U.S. Centers for Disease Control and Prevention. It is a part of the publication CDC HIV/Hepatitis/STD/TB Prevention News Update. Visit the CDC's website to find out more about their activities, publications and services.