QuantiFERON in New York City

American Thoracic Society 2010 International Conference, May 14-19, 2010 • New Orleans

Link here and here, lots on QFT and this one caught my eye;

Treatment Acceptance And Completion Rates For Latent Tuberculosis Infection After Implementation Of QuantiFERON®-TB Gold, New York City

J. Kessler1, S. Ahuja2, A. Crossa3, T. G. Harris4
1New York, NY, United States of America, 2New York City Department of Health and Mental Hygiene, New York, NY, United States of America, 3New York City Department of Health and Mental Hygeine, New York, United States of America, 4New York City Department of Health and Mental Hygeine, New York, NY, United States of America

Corresponding author's email: jak2182@columbia.edu

Rationale: Treatment of latent tuberculosis infection (LTBI) among high-risk populations is part of the tuberculosis (TB) control strategy in the United States. Use of the tuberculin skin test (TST) for LTBI diagnosis among individuals who received the Bacille Calmette-Guérin (BCG) vaccine is complicated by the cross-reaction of TST antigens with the BCG causing false-positive results which can lead to patient and physician reluctance to initiate LTBI treatment. QuantiFERON®-TB Gold (QFT-G) lacks this cross-reaction. We therefore sought to study the impact of implementing QFT-G testing on LTBI treatment initiation and completion at NYC chest clinics.

Methods: QFT-G results from 10/2006–12/2008 in NYC Bureau of TB Control chest clinics were obtained from the electronic medical record system. Characteristics of patients who did and did not initiate and complete treatment were compared using the Wilcoxon rank-sum (continuous variables) or chi-square (categorical variables) tests and multivariate logistic regression. The proportions of patients who initiated and completed treatment among patients tested with QFT-G were compared to those tested with TST from 10/2004–9/2006

Results: Among 38,450 patients tested with QFT-G, 2368 (6%) tested positive, 35,626 (93%) tested negative, and 456 (1%) had an indeterminate result. Among those who tested QFT-G+, 1197 (51%) initiated treatment; of those, 595 (50%) completed treatment. Among LTBI patients, contacts [72%(122/169) vs. 49%(1075/2199) non-contacts] and foreign-born persons [57%(972/1719) vs. 34%(225/664) US-born] were more likely to initiate treatment (both p<0.0001). In multivariate analysis younger age [adjusted odds ratio (adjOR)=0.96, 95% confidence interval(CI)=0.95-0.96], foreign-birth (adjOR=1.87, 95%CI=1.47-2.37), and being a contact (adjOR=2.77, 95%CI=1.91-4.03) were associated with initiation. Among treatment initiators, foreign-born persons [57% (558/972) vs. 36% (81/225);p<0.0001], and contacts [(69% (84/122) vs. 52% (555/1075);p=0.0003] were more likely to complete LTBI treatment. In multivariate analysis these factors remained associated with treatment completion (foreign-birth adjOR=1.92, 95%CI=1.35-2.72, contact adjOR=1.75, 95%CI=1.15-2.67). Historically, among patients tested with TST, 19% (6932/37,713) tested positive; 50% (3500/6932) initiated LTBI treatment and 44% (1545/3500) completed treatment. The proportion of patients initiating LTBI treatment did not differ based on test (p=0.961); however, the proportion completing treatment was higher for those tested with QFT-G (p<0.0001).

Conclusions: QFT-G implementation has greatly reduced the number of persons begun on LTBI treatment and appears to have increased completion. Additional studies are needed to determine whether QFT-G use results in a sustained increase in treatment completion and occurs in settings other than NYC TB clinics. The reasons behind the higher completion but not initiation proportions also need to be elucidated.