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Replacing clinic-based tests with home-use tests may increase HIV prevalence among Seattle men who have sex with men: evidence from a mathematical model.

ABSTRACT: Home-use tests have potential to increase HIV testing but may increase the rate of false-negative tests and decrease linkage to HIV care. We sought to estimate the impact of replacing clinic-based testing with home-use tests on HIV prevalence among men who have sex with men (MSM) in Seattle, Washington.We adapted a deterministic, continuous-time model of HIV transmission dynamics parameterized using a 2003 random digit dial study of Seattle MSM. Test performance was based on the OraQuick In-Home HIV Test (OraSure Technologies, Inc, Bethlehem, PA) for home-use tests and, on an average, of antigen-antibody combination assays and nucleic acid amplification tests for clinic-based testing.Based on observed levels of clinic-based testing, our baseline model predicted an equilibrium HIV prevalence of 18.6%. If all men replaced clinic-based testing with home-use tests, prevalence increased to 27.5% if home-use testing did not impact testing frequency and to 22.4% if home-use testing increased testing frequency 3-fold. Regardless of how much home-use testing increased testing frequency, any replacement of clinic-based testing with home-use testing increased prevalence. These increases in HIV prevalence were mostly caused by the relatively long window period of the currently approved test. If the window period of a home-use test were 2 months instead of 3 months, prevalence would decrease if all MSM replaced clinic-based testing with home-use tests and tested more than 2.6 times more frequently.Our model suggests that if home-use HIV tests replace supplement clinic-based testing, HIV prevalence may increase among Seattle MSM, even if home-use tests result in increased testing.

SUBMITTER: Katz DA

PROVIDER: S-EPMC3955208 | biostudies-literature | 2014 Jan

REPOSITORIES: biostudies-literature

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Replacing clinic-based tests with home-use tests may increase HIV prevalence among Seattle men who have sex with men: evidence from a mathematical model.

Katz David A DA Cassels Susan L SL Stekler Joanne D JD

Sexually transmitted diseases 20140101 1

<h4>Background</h4>Home-use tests have potential to increase HIV testing but may increase the rate of false-negative tests and decrease linkage to HIV care. We sought to estimate the impact of replacing clinic-based testing with home-use tests on HIV prevalence among men who have sex with men (MSM) in Seattle, Washington.<h4>Methods</h4>We adapted a deterministic, continuous-time model of HIV transmission dynamics parameterized using a 2003 random digit dial study of Seattle MSM. Test performanc ...[more]

PMID: 24335742

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Project description:IntroductionDual point-of-care tests (POCTs) for detecting antibodies to HIV and syphilis have been developed for use with venous whole blood, serum/plasma or finger-prick capillary whole blood. Several tests are commercially available showing encouraging performance compared with 'gold-standard' reference tests in laboratory-based studies. However, data on their performance in the field are limited. This prospective cross-sectional study will conduct a clinic-based evaluation to assess the performance characteristics and acceptability to end-users of two dual HIV/syphilis POCTs for the screening of HIV and syphilis among men who have sex with men (MSM), sex workers (SWs) and pregnant women (PW). This master protocol outlines the overall research approach that will be used in seven countries.Method and analysisMSM, SWs and PW presenting at clinic evaluation sites in high, low and middle-income countries will be enrolled. The (WHO preapproved) POCTs to be evaluated are SD Bioline HIV/Syphilis Duo (Abbott) and Dual Path Platform HIV-Syphilis Assay (Chembio). Finger-prick blood will be collected to perform POCTs and compared with laboratory results (venepuncture blood). Procedures will be carried out by trained healthcare staff and tests performed according to the manufacturers' directions. Sample size was calculated based on local prevalence of HIV and syphilis. The sensitivity, specificity, positive and negative predictive values for each POCT will be calculated. The study is ongoing with recruitment expected to be completed in all countries by mid to late 2021.Ethics and disseminationThis core protocol was independently peer reviewed and approved by the Research Project Review Panel (RP2) of the WHO Department of Sexual and Reproductive Health and Research and by the WHO Ethics Review Committee (ERC). The protocol has been adapted to individual countries and approved by RP2, ERC and institutional review boards at each site. Results will be disseminated through peer-reviewed journals and relevant conferences.

Project description:BACKGROUND:The rise of gonococcal antimicrobial resistance highlights the need for strategies that extend the clinically useful life span of antibiotics. Because there is limited evidence to support the current practice of switching empiric first-line antibiotic when resistance exceeds 5% in the population, our objective was to compare the impact of alternative strategies on the effective life spans of antibiotics and the overall burden of gonorrhea. METHODS AND FINDINGS:We developed and calibrated a mathematical model of gonorrhea transmission among men who have sex with men (MSM) in the United States. We calibrated the model to the estimated prevalence of gonorrhea, the rate of gonorrhea cases, and the proportion of cases presenting symptoms among MSM in the US. We used this model to project the effective life span of antibiotics and the number of gonorrhea cases expected under current and alternative surveillance strategies over a 50-year simulation period. We demonstrate that compared to the current practice, a strategy that uses quarterly (as opposed to yearly) surveillance estimates and incorporates both the estimated prevalence of resistance and the trend in the prevalence of resistance to determine treatment guidelines could extend the effective life span of antibiotics by 0.83 years. This is equivalent to successfully treating an additional 80.1 (95% uncertainty interval: [47.7, 111.9]) gonorrhea cases per 100,000 MSM population each year with the first-line antibiotics without worsening the burden of gonorrhea. If the annual number of isolates tested for drug susceptibility is doubled, this strategy could increase the effective life span of antibiotics by 0.94 years, which is equivalent to successfully treating an additional 91.1 (54.3, 127.3) gonorrhea cases per 100,000 MSM population each year without increasing the incidence of gonorrhea. Study limitations include that our conclusions might not be generalizable to other settings because our model describes the transmission of gonorrhea among the US MSM population, and, to better capture uncertainty in the characteristics of current and future antibiotics, we chose to model hypothetical drugs with characteristics similar to the antibiotics commonly used in gonorrhea treatment. CONCLUSIONS:Our results suggest that use of data from surveillance programs could be expanded to prolong the clinical effectiveness of antibiotics without increasing the burden of the disease. This highlights the importance of maintaining effective surveillance systems and the engagement of policy makers to turn surveillance findings into timely and effective decisions.

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Replacing clinic-based tests with home-use tests may increase HIV prevalence among Seattle men who have sex with men: evidence from a mathematical model.

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Replacing clinic-based tests with home-use tests may increase HIV prevalence among Seattle men who have sex with men: evidence from a mathematical model.

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