Sexually transmitted diseases and the increased risk for HIV transmission: implications for cost-effectiveness analyses of sexually transmitted disease prevention interventions

We estimated the annual number and cost of new HIV infections in the United States attributable to other sexually transmitted diseases (STDs). We used a mathematical model of HIV transmission to estimate the probability that a given STD infection would facilitate HIV transmission from an HIV-infected person to his or her partner and to calculate the number of HIV infections due to these facilitative effects. In 1996, an estimated 5,052 new HIV cases were attributable to the four STDs considered here: chlamydia (3,249 cases), syphilis (1,002 cases), gonorrhea (430 cases), and genital herpes (371 cases). These new HIV cases account for approximately $985 million U.S. in direct HIV treatment costs. The model suggested that syphilis is far more likely than the other STDs (on a per-case basis) to facilitate HIV transmission. This analysis provides a framework for incorporating STD-attributable HIV treatment costs into cost-effectiveness analyses of STD prevention programs.     

The value of screening for sexually transmitted diseases in an HIV clinic

Because bacterial sexually transmitted diseases (STDs) facilitate HIV transmission, screening for and treatment of STDs among HIV-infected persons should prevent HIV spread to partners. Before screening programs for gonorrhea and Chlamydia infection should be widely established in HIV clinics, it is useful to know the prevalence of these infections. This study analyzed the results of a urine-based screening program for gonorrhea and Chlamydia in a New Orleans HIV clinic and compared the positivity rates to the prevalence in the local community. Among persons screened in the HIV clinic, 1.7% (46/2629) had gonorrhea and 2.1% (56/2629) had Chlamydia infection. Among persons aged 18-29 years, the test positivity for gonorrhea was similar in the HIV clinic to that of persons in sociodemographically similar community samples (3.1 versus 2.4%, adjusted odds ratio 1.6, P = 0.11) and the test positivity for Chlamydia infection was lower (5.4% versus 10.5%, adjusted odds ratio 0.6, P < 0.01). Based on a previously published mathematical model, it was estimated that treatment of all 46 gonorrhea and 56 Chlamydia infections in the HIV clinic may have averted 9 HIV infections among sex partners and saved far more in future medical costs than the cost of the screening. Routine screening for gonorrhea and Chlamydia infection should be considered in HIV clinics.     

HIV seroincidence among patients at clinics for sexually transmitted diseases in nine cities in the United States

Although the numbers of newly reported diagnoses of AIDS decreased in the 1990s, it is not clear whether they reflect a decreasing number of new HIV infections. Direct measurement of HIV incidence through follow-up cohort studies is difficult and costly. We estimated HIV incidence and trends in incidence among men who have sex with men (MSM) and heterosexual men and women at clinics for sexually transmitted diseases (STDs) by using a recently developed serologic testing algorithm that requires only a single blood specimen. Cross-sectional anonymous serosurveys were conducted at 13 STD clinics in nine cities in the United States from 1991 through 1997. Before anonymous HIV testing, demographic and clinical information was abstracted. Of 129,774 specimens tested, 362 (0.28%) were from persons estimated to be recently infected. Incidence among MSM was 7.1% (95% confidence interval (CI): 4.8-10.3), 14 times higher than that among heterosexuals, which was 0.5% (CI: 0.4- 0.7). Incidence among MSM and heterosexuals remained unchanged during the time studied. Decreasing rates of new AIDS diagnoses in the 1990s do not reflect stable rates of new HIV infections among MSM and heterosexual patients attending these clinics.     

Utility of behavioral changes as markers of sexually transmitted disease risk reduction in sexually transmitted disease/HIV prevention trials

Most sexually transmitted disease (STD)/HIV sexual risk reduction intervention trials are evaluated using behavioral outcomes as their main indicators of intervention effectiveness. How good are behavioral measures as surrogate markers for STD infection? Do the behavioral changes that are commonly assessed in risk reduction interventions accurately reflect changes in STD risk? We applied a mathematical model of STD/HIV transmission to empiric data from a large HIV prevention intervention to estimate pre- to postintervention changes in intervention participants' STD risk. We then used the coefficient of determination (R(2)) to assess the strength of association between changes in STD risk and changes in three behavioral measures: proportion of acts of intercourse for which condoms were used, number of sex partners, and number of acts of unprotected intercourse. The results indicate that change in the number of acts of unprotected intercourse is a superior marker of STD risk changes for less infectious STDs such as HIV, whereas change in the number of partners may be preferable for highly infectious STDs such as gonorrhea. Changes in the proportion of acts of intercourse for which condoms were used were not strongly correlated with changes in STD risk under most of the conditions examined in this analysis. The utility of different measures of sexual behavior change as markers for changes in STD risk and, hence, expected incidence, depends on the infectivity and prevalence of the target STD.     

Screening to reduce transmission of sexually transmitted diseases in semen used for artificial insemination

The practice of artificial insemination by donor semen is increasing in the United States. Many sexually transmitted organisms are found in semen, but screening procedures for the detection of these agents in donor semen have not been standardized. Sexually transmitted organisms have been transmitted during artificial insemination by donor, and such transmission can cause local, disseminated, or fatal disease in the recipient woman and may harm the fetus or newborn. Therefore, screening of both the donor and the donated semen is necessary to avoid infectious complications. Because semen samples cannot be evaluated completely on the day of donation, the use of fresh semen for artificial insemination should be discouraged. Until accurate, rapid diagnostic tests are available, only frozen semen that has been appropriately screened should be used.     

HIV infection and sexually transmitted diseases in female commercial sex workers in China

A cross-sectional survey was conducted among female commercial sex workers (FSWs) in Zhengzhou, China, to estimate rates of HIV infection and sexually transmitted diseases (STDs) and to document their sexual behavior patterns from October 2000 to January 2001. FSWs were recruited by the snowball sampling technique and were interviewed at their working environments anonymously. This strategy resulted in high rates of response (92%) and concordance (98%) to sensitive questions. A total of 621 FSWs were enrolled. One direct FSW and 1 indirect FSW were positive for antibodies to HIV in oral fluids (prevalence of HIV infection, 1.4% and 0.2%, respectively). A history of STDs was reported by 49% of the FSWs. Most FSWs (87%) reported inconsistent condom use. Ten percent of FSWs recognized their clients as drug users. A few FSWs (2.2%) were injecting drug users, of whom 2 reported incidents of sharing needles/syringes with other injecting drug users. Direct FSWs had more risk characteristics and were more vulnerable to HIV infection and STDs than indirect FSWs. Inconsistent use of condoms and a high level of STDs underscore the urgent need to implement intervention strategies and condom promotion, particularly among direct sex workers in China.     

Interactions of HIV, other sexually transmitted diseases, and genital tract inflammation facilitating local pathogen transmission and acquisition

Despite several decades of clinical trials assessing the impact of etiological treatment of sexually transmitted diseases (STDs) to decrease HIV acquisition and transmission, almost all of these trials have not proven to be efficacious. Increasing evidence suggests that specific STD treatment alone may not be sufficient to alter the genital tract inflammatory milieu that is created by STDs. This paper examines the associations between STDs and HIV susceptibility and infectiousness, and considers the role of chronic and refractory inflammation to create an environment that potentiates HIV and STD transmission and acquisition by reviewing biological, observational, and clinical trial data.     

Human immunodeficiency virus infection among patients attending clinics for sexually transmitted diseases

To assess the prevalence and associated risk factors for human immunodeficiency virus (HIV) infection in patients attending inner-city clinics for sexually transmitted diseases in Baltimore, we screened 4028 patients anonymously, of whom 209 (5.2 percent) were seropositive for HIV. HIV-seropositivity rates were higher among men (6.3 percent) than women (3.0 percent) (P less than 0.001) and among blacks (5.0 percent) than whites (1.2 percent) (P less than 0.02). Among men, but not women, HIV seroprevalence increased markedly and steadily up to the age of 40. In men, HIV seropositivity was independently associated with increased age, black race, a history of homosexual contact, and the use of parenteral drugs. In women, a history of parenteral drug use or of being a sexual partner of a bisexual man or parenteral drug user were independently predictive of HIV seropositivity. In men, HIV seropositivity was also associated with a history of syphilis or a reactive serologic test for syphilis, and in women, with a history of genital warts. Since these associations were independent of the type and number of reported sexual partners, they raise the possibility that sexually transmitted diseases that disrupt epithelial surfaces may be important in the transmissibility of HIV. In addition, on a self-administered questionnaire, one third of HIV-infected men and one half of infected women did not acknowledge previous high-risk behavior for HIV exposure. These data suggest that patients at clinics for sexually transmitted diseases represent a group at high risk for HIV infection, and that screening, counseling, and intensive education should be offered to all patients attending such clinics.     

Beta-lactams in sexually transmitted diseases: Rationale for selection and dosing regimens

A review is given of the selection and rationale of optimal treatment regimens for patients with sexually transmitted pathogens, e.g. in cases of gonorrhea, chlamydial infections, chancroid, syphilis, pelvic inflammatory diseases and ophthalmia neonatorum. The scientific basis for the selection of a beta-lactam agent is discussed, including dose, MIC, the critical serum level and maintenance interval, and the duration of therapy. Except in the case of penicillinase-producingNeiserria gonorrhoeae, penicillin remained until recently the most effective agent available against many sexually transmitted diseases. However, ceftriaxone, a new third-generation cephalosporin, has been shown to have a long half-life (8 h) and excellent in vitro efficacy againstNeiserria gonorrhoeae (including penicillinase-producing strains) andHaemophilis ducreyi. In view of its exceptional clinical efficacy against both gonorrhea and chancroid, clinical studies of its efficacy against other sexually transmitted diseases appear warranted.     

Hiv risk behavior in male and female russian sexually transmitted disease clinic patients

Russia is experiencing one of the fastest growing HIV epidemics in the world. Russian sexually transmitted disease (STD) clinic patients are at elevated risk for infection with HIV and other STDs due to unsafe sexual behaviors. Future risk reduction intervention efforts for this group must be grounded in a solid understanding of the factors associated with risky behaviors. We collected information about the sexual behaviors, substance use, protective strategies, and HIV-related attitudes of 400 high-risk men and women presenting at an STD clinic in a major Russian metropolis. Alcohol use in conjunction with sexual activity was common in this sample (85%). One-third of study participants had more than 1 partner in the past 3 months, and about half (48%) of the sample had previously been diagnosed with an STD. However, despite this evidence of high-risk behavior, most participants (67%) reported using condoms less than half the time. High-risk behavior was associated with substance use and lower perceived severity of AIDS. Self-protective strategies differed by gender: men reported higher condom use rates whereas women reported efforts to limit their number of sexual partners. This study has important implications for the development of culturally tailored interventions to help stem the spread of HIV in Russia.     

Examining racial disparities in HIV: lessons from sexually transmitted infections research

Racial differences in the prevalence and incidence of HIV infection and AIDS diagnoses in the United States are striking. These differences have been recognized for nearly 20 years, yet they are not well investigated. In this article, we examine 15 factors identified in the sexually transmitted infection (STI) literature to explain the presence of racial/ethnic disparities in STIs. We review findings from these studies and offer suggestions for future research, with the goal of further understanding and reducing disparities in HIV. In general, the STI literature shows that an evaluation of individual behavior is necessary but insufficient on its own to account for racial/ethnic disparities in STIs. Population parameters should be included within models that traditionally include individual-level factors. The 15 factors can be categorized into 3 broad overarching themes: behavioral, prevention participation, and biologic explanations of differentials in STI transmission and infection. Future research that focuses on only 1 of the 15 factors discussed in this review, to the exclusion of others, is likely to yield poor outcomes. Conversely, an emphasis on the interactions of several factors is more likely to produce effective public health interventions and reductions in HIV transmission.     

Declining HIV incidence among patients attending sexually transmitted infection clinics in Pune, India

OBJECTIVE: A recent report suggesting declining HIV transmission rates in southern India has been based on HIV seroprevalence data to estimate HIV incidence. We analyzed HIV incidence rates among 3 cohorts (male, female non-sex worker, female sex worker [FSW]) presenting to sexually transmitted infection (STI) clinics in Pune, India over 10 years. METHODS: Between 1993 and 2002, consenting HIV-uninfected individuals were enrolled in a prospective study of the risks for HIV seroconversion. Standardized HIV incidence estimates were calculated separately for the 3 cohorts. RESULTS: HIV acquisition risk declined by more than 70% for FSWs (P = 0.02) and men (P < 0.001) attending the STI clinics. There was no significant reduction in HIV incidence among women attending STI clinics (P = 0.74). The decline in HIVacquisition risk among male patients with STIs was associated with an increase in reported condom use with recent FSW contact and a decrease in genital ulcer disease. CONCLUSIONS: We report the first direct evidence for a decline in HIV incidence rates in FSWs and male patients with STIs over time. The lack of change in HIV infection risk among non-sex worker women highlights the need for additional targeted HIV prevention interventions.     

High rates of HIV testing despite low perceived HIV risk among African-American sexually transmitted disease patients

PURPOSE: In the current diagnosis-based, human immunodeficiency virus (HIV) prevention climate, previous testing among persons at elevated HIV risk has cost and efficacy implications, as it signals continued behavioral risk, limited HIV knowledge or overuse of services. This study sought to determine the proportion of African Americans newly seeking sexually transmitted disease (STD) diagnosis who previously had obtained HIV counseling and testing. METHODS: This was a clinic-based, cross-sectional survey of African-American adults (N=408) seeking STO diagnosis at a public STD clinic located in a high-HIV and STD prevalence city in the U.S. south. MAIN FINDINGS: Eighty-four percent of respondents had previously obtained HIV counseling and testing: 68% had previously obtained care at the clinic. Sixty-five percent of respondents perceived themselves as having low or no HIV risk. Seventy-two percent correctly answered > or = 3 of 4 HIV knowledge items. CONCLUSIONS: Although diagnosis-based HIV prevention initiatives promote HIV counseling and testing for both primary and secondary HIV prevention, these findings suggest that many African-American STD patients remain at risk following testing. Future research should explore how the counseling portion of standard HIV counseling and testing influences subsequent knowledge, attitudes, risk perceptions and behaviors.     

Prevalence of genital human papillomavirus infections in patients at a sexually transmitted diseases clinic

The human papillomavirus was detected in cervicovaginal cells by the polymerase chain reaction in 14 of 37 (37.8 %) patients attending a sexually transmitted disease (STD) clinic and in 6 of 43 healthy young women (14.0 %) undergoing routine gynecologic examinations who served as controls. The results indicated that even the more malignant types of human papillomaviruses were not uncommon among the control group, and that the prevalence of human papillomavirus infection was significantly higher in STD clinic patients than in the control group. These findings confirm the suggestion that factors other than human papillomavirus infections may be involved in the pathogenesis of cervical cancer.     

Health care seeking behaviour of patients with sexually transmitted diseases: determinants of delay behaviour

The study aimed to determine the factors associated with a delay in seeking health care for symptoms of sexually transmitted diseases (STDs) among a sample of 1482 patients attending STD clinics. Of the sample 78% were male, 58% sought help from the clinic within the first 6 days of noticing symptoms, 24% waited between 7 and 10 days and 17% waited longer than 10 days before seeking health care. Patients who delayed were those who treated themselves prior to seeking health care, who were female, whose friends waited before seeking treatment, who held misconceptions regarding the cause of STDs, who perceived STDs not to be serious and who valued personal autonomy in sexual behaviours less and had less positive outcome expectations of refusing sex. The data suggest that targeted interventions should be directed specifically at women and the youth. Early health care seeking could be facilitated through improved basic knowledge regarding STDs, control over one's own sexual behaviour and social support for early health care seeking.     

The cost-effectiveness of treating male trichomoniasis to avert HIV transmission in men seeking sexually transmitted disease care in Malawi

OBJECTIVE: Allocation of funds to program areas where they may have an impact is critical to the success of any HIV control program. We examined the cost-effectiveness of providing first-line treatment for male trichomoniasis in Malawi, a condition not commonly considered in syndromic management throughout sub-Saharan Africa. METHODS: We used decision tree analysis to assess program costs and outcomes among a 1-year population of male sexually transmitted disease (STD) clinic attendees estimated at 10,000 in Lilongwe. Our main outcomes were program costs from the government perspective and HIV infections averted. We conducted univariate and multivariate sensitivity analyses on selected parameters. RESULTS: In our study population of male STD clinic attendees with an HIV prevalence of 44% and a Trichomonas vaginalis prevalence of 20%, including universal metronidazole as a first-line treatment for trichomoniasis at $0.05 per dose would increase program costs by $277 (year 2000 US dollars) and avert 23 cases of HIV. The incremental cost-effectiveness ratio (ICER) over the current STD management guidelines was $15.42 per case of HIV averted. The number of HIV infections averted under sensitivity analysis ranged from 2 to 52, with attendant ICERs varying from cost savings to $162.92. Consideration of wider social benefits, such as the costs of HIV infections to the individual or the government, would further enhance the cost-effectiveness of this program. CONCLUSIONS: As part of a larger program to control STDs, incorporating metronidazole to treat male trichomoniasis could represent a cost-effective means to reduce HIV transmission in this high-risk group.     

HIV seroconversion among public sexually transmitted disease clinic patients: analysis of risks to facilitate early identification

OBJECTIVES: We identified risks for HIV seroconversion among public sexually transmitted disease (STD) clinic patients. DESIGN: This was a retrospective cohort study conducted January 1993 through October 2002 of STD clinic attendees aged > or =12 years in Baltimore, Maryland. METHODS: A negative HIV enzyme immunoassay (EIA) test was required for staggered cohort entry. Observation time was 30 days to 3 years. The outcome for multivariate Poisson regression was HIV seroconversion (positive EIA and/or Western blot test) compared among patients with or without sexual risk behaviors, drug use, an STD diagnosis, and signs and symptoms at an initial HIV test. RESULTS: One hundred twenty-five HIV seroconversions occurred among 10,535 individuals and 13,693 person-years of observation, for an incidence of 0.91 HIV seroconversions per 100 person-years (95% confidence interval [CI]: 0.76 to 1.09). Median time to HIV seroconversion was 1.54 years (95% CI: 1.11 to 1.73). In multivariate analysis, increased HIV seroconversion risk was associated with older age, drug use, a sexual partner with syphilis or HIV, genital ulcers, and gonorrhea. HIV incidence per 100 person-years was 4.86 for subjects with an HIV-positive sexual partner, 3.06 for those with injection drug use, and 2.40 for those with genital ulcers. CONCLUSIONS: We found a high rate of HIV seroconversion among STD clinic patients with specific risks. Algorithms with HIV RNA testing targeted to patients at the highest risk for seroconversion may optimize prevention and resource utilization.