This study is the most recent and comprehensive assessment of the epidemiology of pleural TB in the United States. Although the total number of pleural TB cases decreased between 1993 and 2003, the proportion of pleural TB cases compared to the total number of cases in the United States remained relatively stable (median proportion, 3.6%) [Fig 1]. This confirms earlier estimates and counters thoughts that those estimates were low. The total number and proportion of pulmonary TB cases have been steadily decreasing.
However, concerns about the underreporting of pleural TB owing to frequently negative mycobacterial culture results may continue to raise concerns that our pleural TB incidence findings were underestimated. Pleural TB is thought to arise primarily as the sequela of primary pulmonary TB infection or as the reactivation of pulmonary TB disease. The decline in the numbers of both pleural and pulmonary TB cases reflects the overall decline in TB in the United States since the resurgence (ie, 1986 to 1992). This can be attributed to the aggressive efforts of the public health community and health-care providers, which resulted in improved diagnostic, therapeutic, and prevention strategies.