Increasing proportions of advanced pulmonary tuberculosis reported in the United States: are delays in diagnosis on the rise?

RATIONALE: Delays in the diagnosis of tuberculosis (TB) can result in progression to advanced disease. Patients with pulmonary TB and advanced disease are more likely to transmit disease and fail treatment.
OBJECTIVES: To examine clinical, epidemiological, and geographic factors associated with advanced pulmonary TB to further understanding of delayed diagnosis and transmission.
METHODS: Pulmonary tuberculosis cases in persons older than 15 years of age reported to the U.S. National Tuberculosis Surveillance System with advanced disease (cavitation on chest radiograph and acid-fast bacilli smear-positive sputum result) were compared with those without advanced disease using trend and binomial regression analysis.
MEASUREMENTS AND MAIN RESULTS: There were 35,584 cases of advanced pulmonary tuberculosis (APT) and 125,077 cases of non-APT reported from 1993 through 2006. Proportions of pulmonary TB cases with APT increased from 18.5% in 1993 to 26.1% in 2006, and the increase in the proportion of APT was most notable for national TB rates below 6.6 per 100,000. At the county level, the association between APT and low TB incidence has grown incrementally since 2000. The proportion of APT increased greatest among whites (65.4%), the employed (63.3%), and the U.S. born (59.2%). The prevalence of APT was 44% greater among persons with multidrug-resistant TB compared with those without it.
CONCLUSIONS: This study highlights the need for TB diagnosis at early stages of the disease to minimize APT and decrease the risk of transmission. Additional efforts should concentrate on reducing time to treatment initiation in low-incidence areas and among groups traditionally seen as being at low risk for TB disease.