529. Latent Tuberculosis Infection Screening among HIV-Infected Patients: Tuberculin Skin Test vs. Interferon-Gamma Release Assay
Session: Poster Abstract Session: Latent Tuberculosis Diagnosis and Management
Thursday, October 27, 2016
Room: Poster Hall
  • LTBI Poster 10-12-2016.pdf (212.5 kB)
  • Background: National guidelines recommend screening for latent tuberculosis infection (LTBI) in all HIV+ patients. The study objective was to 1) measure adherence to guidelines and 2) determine whether transitioning from the tuberculin skin test (TST) to the interferon-gamma release assay (IGRA) improved screening adherence among HIV+ patients entering care at an HIV primary care clinic in Philadelphia, PA.

    Methods: A retrospective cohort study using medical chart review was conducted using multivariable modified Poisson regression models to examine the association between LTBI screening within twelve months of entering care and factors of interest, including latent tuberculosis screening method. Successful screening was defined as placement and reading of a TST, performance of an IGRA, or receipt of records from an outside clinic documenting prior testing or treatment since HIV diagnosis.

    Results: Overall, 32% (n=118/372) of patients received LTBI screening within twelve months of entering care. Transitioning to IGRA-based screening improved adherence (28% to 37%) but adherence remained suboptimal. In multivariable regression analysis, IGRA screening (adjusted risk ratio (ARR): 1.46, 95% confidence limit (CL): 1.07, 1.99) and male sex (ARR: 1.48, 95%CL: 1.06, 2.09) was associated with a higher likelihood of LTBI screening.

    Conclusion: Transitioning from TST to IGRA-based screening improved adherence to screening guidelines; however, less than 40% of HIV+ patients received LTBI screening. Further work is needed on how to most effectively increase screening rates among HIV+ patients in a primary care setting.

    Table 1. Multivariable Risk Ratios for Successful Tuberculosis Screening Endpoint by Latent Tuberculosis Screening Method, Sociodemographic, and Clinical Characteristics, N=372

    Adjusted Risk Ratioa

    95% CL

     Screening Method (IGRA vs. TST)

    1.46 (1.07, 1.99)

     Male vs. Female

    1.48 (1.06, 2.09)

     CD4 closest to initial visit

     ≤ 200 cells/uL

     201-350 cells/uL

     351-500 cells/uL

     >500 cells/uL

    0.96 (0.65, 1.44)

    1.19 (0.80, 1.77)

    1.03 (0.68, 1.56)


     Current smoker

    1.06 (0.79, 1.43)

     Current illicit substance use

    1.00 (0.72, 1.39)

     Living situation



     In patient/long term care


    1.12 (0.67, 1.85)

    0.71 (0.48, 1.05)

     Transfer patient

    1.41 (0.99, 2.01)

    a Adjusted for variables in table as well as age and race/ethnicity. Boldface font, p < 0.05.

    Joella Adams, MPH1, Ashley Andrews, MPH2, Chanelle Howe, PhD1 and Christopher Vinnard, MD3, (1)Department of Epidemiology, Brown School of Public Health, Providence, RI, (2)Drexel School of Public Health, Philadelphia, PA, (3)Department of Medicine, Division of Infectious Diseases & HIV Medicine, Drexel University College of Medicine, Philadelphia, PA


    J. Adams, None

    A. Andrews, None

    C. Howe, None

    C. Vinnard, None

    Findings in the abstracts are embargoed until 12:01 a.m. CDT, Wednesday Oct. 26th with the exception of research findings presented at the IDWeek press conferences.