530. Risk Factors for Missed Study Visits Among Patients with a Positive Screening Test for Latent Tuberculosis Infection (LTBI)
Session: Poster Abstract Session: Latent Tuberculosis Diagnosis and Management
Thursday, October 27, 2016
Room: Poster Hall
Background: Ascertainment of active TB disease endpoints in studies of latent tuberculosis infection (LTBI) is critical. Identification of groups at risk for missed follow-up visits is important for targeting interventions to improve visit attendance.

Methods: The Tuberculosis Epidemiologic Studies Consortium is conducting a multicenter study evaluating the tuberculin skin test (TST) and 2 interferon gamma release assays (IGRAs), QuantiFERON Gold in-tube and T-SPOT TB. Patients with a positive TST or IGRA (using standard United States cut-points) enrolled in Nashville, Tennessee April 2012- June 2015 were included. Study follow-up visits were conducted in-person or by phone every 6 months for 2 years to ascertain active TB endpoints; compensation was provided. Modified Poisson Regression estimated the adjusted relative risk (aRR) of any one of 4 possible missed study visits. Generalized estimating equations accounted for multiple outcomes per individual. Variables with p<0.10 in univariate analysis were included in adjusted analyses; age, sex, and study visit number were also included. Interactions were assessed; none were significant.

Results: Among 185 persons and 597 study visits, 99 visits (17%) were missed. Those reporting Bacillus Calmette–Guérin (BCG) vaccination and current smoking were at increased risk for missed study visits; there was a trend toward increased risk of missed study visits among non-English speakers (32% Nepali, 31% Burmese, 10% Arabic) (Table 1).

Conclusion: In this population, BCG vaccination and current smoking may be predictors of missed study visits; linguistic barriers may also contribute. Interventions, such as enhanced LTBI education, targeted toward these groups may improve follow-up for future LTBI studies.

Table 1. Adjusted Model


N (%) or Median (Interquartile Range)

aRR (95% Confidence Interval)


31 (25-43)

1.01 (0.99-1.03)

Male Sex

105 (57%)

1.33 (0.79-2.23)

Non-English Speaking

120 (65%)

2.06 (0.85-5.01)

High School/GED Education

77 (42%)

0.78 (0.36-1.67)

BCG vaccination

99 (54%)

1.80 (1.10-2.95)

Current smoker

32 (17%)

2.25 (1.29-3.92)


14 (8%)

0.18 (0.02-1.42)

LTBI Treatment Offered

114 (62%)

1.17 (0.60-2.28)

Both TST and IGRA positive

119 (64%)

1.32 (0.69-2.53)

Marian Lacy, MD1, Fernanda Maruri, MPH2,3, Kristian Atchley, RN, BSN3,4, Timothy R. Sterling, MD, FIDSA2,3 and April Pettit, MD, MPH2,3, (1)Department of Internal Medicine/Pediatrics, Vanderbilt University, Nashville, TN, (2)Department of Medicine, Division of Infectious Diseases, Vanderbilt University, Nashville, TN, (3)Vanderbilt Tuberculosis Center, Vanderbilt University, Nashville, TN, (4)Nashville Metropolitan Public Health Department, Nashville, TN


M. Lacy, None

F. Maruri, None

K. Atchley, None

T. R. Sterling, None

A. Pettit, None

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