Pulmonary vs. extra-pulmonary tuberculosis hospitalizations in the US [1998-2014]

Few studies have explored the relative burden and trends in pulmonary (PTB) vs. extra-pulmonary (EPTB) tuberculosis in the United States using a nationally representative sample.

This study examined trends in hospitalization rates, length-of-stay (LOS), in-hospital mortality and inflation-adjusted charges, for PTB vs. EPTB using the Nationwide/National Inpatient Sample (NIS) from 1998 to 2014. Descriptive and multivariable analyses (linear, negative binomial and logistic) were utilized adjusting for demographics, co-morbidity and hospital characteristics.

During the study period there were a survey-adjusted, estimated 258,631 PTB (75.5%), 76,476 EPTB (22.3%) and 7552 concurrent PTB and EPTB (2.2%) discharges. Whites accounted for 27.6% of PTB, 21.9% of EPTB and 17.6% of concurrent discharges; and self-pay or no insurance accounted for 22.2%, 18.4%, and 25.9%, respectively. EPTB was more common among blacks (22.5%), and combined TB more common among Hispanics (24.8%). Mean LOS was 11.4 days, 13.2 days, and 19.5 days; with mean nominal charges of $48,031, $62,255, and $89,364 for PTB, EPTB and combined TB respectively. Inpatient mortality for all three groups was approximately 5.7%. Miliary TB and TB of meninges and central nervous system were positively associated with mortality (odds ratios of 2.44 and 2.11, respectively), as was alcohol abuse (OR 1.21). Trend analyses showed decreased hospitalizations for all TB types, no change in LOS trends, decreased mortality for PTB and ETB and increased charges for PTB and ETB from 1998 to 2014. Increased utilization, higher charges and higher risk of mortality (to some extent) among the EPTB cases warrant improved methods for screening, diagnosis and treatment.

Though rates of TB hospitalization are declining, EPTB is becoming relatively more common and is more costly compared to pulmonary TB. Screening methods that focus on identification of ETB contrary to current practice guidelines are needed to aid ETB case finding.