Isoniazid Toxicity among an Older Veteran Population: A Retrospective Cohort Study.
BACKGROUND
our objective was to determine the incidence of toxicity among veterans initiating isoniazid therapy for latent tuberculosis infection (LTBI) and determine whether advancing age was a risk factor for toxicity.


METHODS
we performed a retrospective cohort study among all adults initiating isoniazid treatment for LTBI at a Veterans Medical Center from 1999 to 2005. We collected data on patient demographics, co-morbidities, site of initiation, and treatment outcome.


RESULTS
219 patients initiated isoniazid therapy for LTBI during the period of observation, and the completion of therapy was confirmed in 100 patients (46%). Among 18/219 patients (8%) that discontinued therapy due to a documented suspected toxicity, the median time to onset was 3 months (IQR 1-5 months). In an adjusted Cox regression model, there was no association between discontinuation due to suspected toxicity and advancing age (HR 1.03, 95% CI 0.99, 1.07). In contrast, hepatitis C infection was a significant predictor of cessation due to toxicity in the adjusted analysis (HR 3.03, 95% CI 1.08, 8.52).


CONCLUSIONS
cessation of isoniazid therapy due to suspected toxicity was infrequently observed among a veteran population and was not associated with advancing age. Alternative LTBI treatment approaches should be further examined in the veteran population.
Division of Infectious Diseases and HIV Medicine, College of Medicine, Drexel University, 245 N. 15th Street MS 461, New College Building 6314, Philadelphia, PA 19102, USA.
Christopher
C
Vinnard
Anand
A
Gopal
Darren R
DR
Linkin
Joel
J
Maslow