Study Overview
Objective. To evaluate the incidence and demographic factors associated with chlamydia, gonorrhea, and syphilis among HIV-infected persons in Washington, DC.
Design. Descriptive, retrospective cohort study.
Setting and participants. HIV-infected persons enrolled at 13 DC Cohort sites from 2011 to 2015. The DC Cohort is a clinic-based, city-wide, longitudinal observational cohort launched in 2011 to better understand HIV epidemiology in DC, describe clinical outcomes among those in care, and improve the quality of care for people living with HIV in the DC metropolitan area. Eligible participants included those enrolled from 1 January 2011 to 31 March 2015. Participant follow-up time included time from enrollment to 30 June 2015 or until one of these occurred: death, withdrawal from the DC Cohort, or loss to follow-up.
Main outcomes measures. Confirmed cases of chlamydia, gonorrhea, and syphilis, as well as HIV viral loads at the time of sexually transmitted infection (STI) diagnosis as a proxy for HIV transmission risk.
Main results. Around the time of the study, there were approximately 11,235 persons with HIV infection receiving care at the 13 DC Cohort sites, of which 8732 (77.7%) were approached for enrollment. Of those approached, 7004 (80.2%) agreed to participate and provided consent, 948 (10.9%) declined to enroll, 14 (0.2%) withdrew consent, and 766 (8.8%) remained undecided. There were significant differences between those consenting and declining, including female gender (27.8% of those consenting vs 36.1% of those declining, P < 0.001), white race/ethnicity (13.1% of those consenting vs 6.6% of those declining, P < 0.001), and private insurance status (27.6% of those consenting vs 33.2% of those declining, P < 0.001).
Median age of patients was 47 years (interquartile range, 36.5–54.5 years); 71% were male, 76% were non-Hispanic black, 39% were men who have sex with men (MSM), and 29% were heterosexual. 63.8% had public insurance. 6.7% (451/6672) developed an incident STI during a median follow-up of 32.5 months (4% chlamydia, 3% gonorrhea, 2% syphilis); 30% of participants had 2 or more STI episodes. The incidence rate of any STI was 3.8 cases per 100 person-years (95% confidence interval [CI], 3.5–4.1); age 18–34 years, 10.8 (95% CI, 9.7–12.0); transgender women, 9.9 (95% CI, 6.9–14.0); Hispanics, 9.2 (95% CI, 7.2–11.8); and MSM, 7.7 (95% CI, 7.1–8.4). Multivariate regression analysis showed younger age, Hispanic ethnicity, MSM risk, and higher nadir CD4 counts to be strongly associated with STIs. Among those with an STI, 41.8% had a detectable viral load within 1 month of STI diagnosis, and 14.6% had a viral load ≥ 1500 copies/mL.
Conclusion. STIs are highly prevalent among HIV-infected persons receiving care in DC. HIV transmission risk is considerable at the time of STI diagnosis. Interventions toward risk reduction, antiretroviral therapy adherence, and HIV virologic suppression are critical at the time of STI evaluation.
Commentary
Although the number of new HIV cases in Washington, DC, has been decreasing over recent years [1], it still has one of the highest rates of HIV infection in the United States [2]. In this large-scale, single-city analysis, Lucar et al reported on the incidence and factors associated with the development of chlamydia, gonorrhea, and syphilis in a cohort of people living with HIV in care in DC. Consistent with incidence rates among the DC general population [2], chlamydia had the highest incidence, followed by gonorrhea and then syphilis, each with particularly high rates among 18- to 34-year-olds, MSM, transgender women, and Hispanics.
Studies have shown that many people with HIV do not consistently practice safer sex, placing themselves and others at risk for HIV or STI infection/co-infection [3]. While most HIV prevention programs target HIV-negative individuals, targeting sexual risk behaviors in HIV-positive people can prevent the transmission of HIV and other STIs to uninfected individuals and can also prevent co-infections with other STIs [3]. However, effective interventions to maintain long-term behavior change and prevent HIV transmission are needed. In a recent systematic review and meta-analysis by Globerman et al [3] assessing the effectiveness of HIV/STI prevention interventions for people living with HIV, group-level health education interventions were found to be effective in reducing HIV/STI incidence when compared to attention controls. Another intervention type, comprehensive risk counseling and services, was found to be effective in reducing sexual risk behaviors when compared to both active and attention controls. All other intervention types showed no statistically significant effect or had low or very low quality of evidence. Improving strategies to reduce the impact of HIV and STDs may require an understanding of how different populations are experiencing those conditions [1].
This study has several limitations. First, the observational nature of the DC Cohort precluded standardized STI screening for all participants. STIs are frequently asymptomatic, and differences in screening practices can impact the observed STI frequency [4,5]. Subsequently, reported STI incidence rates are likely underestimating the true STI incidence in people with HIV in care in DC. Furthermore, STI screening may provide diagnosis dates distant from the actual time of STI acquisition. Similarly, the study design also limited the availability of HIV viral loads during the same encounter of STI diagnosis. In addition, the population enrolled in the DC Cohort may not be fully representative of the larger HIV-infected population in DC, as enrollment requires some degree of engagement in care, and the demographics of those declining to participate differed somewhat from those who provided consent.
Strengths of the study include its city-wide reach, prospective enrollment of participants, its longitudinal study design, and the large sample size. Also, since the study linked data from clinical sites with data reported to the local health department, this improved the accuracy of STI diagnosis frequency and provided insight into care received for STIs outside of the primary HIV care site.