Increasing likelihood of advanced pulmonary tuberculosis at initial diagnosis in a low-incidence US state

Arkansas, USA.

To investigate the relationship between an increase in the proportion of cases with advanced disease at first diagnosis and the recently observed slowing of the decline in tuberculosis (TB) incidence in low-incidence US states.

We conducted descriptive statistical analyses of de-identified surveillance data of 1246 culture-confirmed TB patients reported in Arkansas during 1996-2013. We then fitted stepwise, multivariate logistic regression models to identify predictors for advanced disease at diagnosis, defined as having either smear-positive sputum or lung cavitation.

From 1996 to 2013, the proportion of new cases with positive sputum smear and cases with lung cavitation increased from 51.6% to 75% and from 37.7% to 50%, respectively. Patients diagnosed during 2006-2013 were more likely to have positive sputum smears (adjusted odds ratio [aOR] 2.55, 95%CI 1.95-3.35) or lung cavitation (aOR 1.49, 95%CI 1.14-1.95) than those diagnosed during 1996-2005. During 1996-2013, age 15-64 years and excessive alcohol use were predictive of positive sputum smear or lung cavitation.

Measures to reduce the proportion of cases with advanced disease at first diagnosis may be helpful to achieve further decline in TB incidence in low-incidence settings.