The Role of Tuberculosis in Chronic Obstructive Lung Disease

Patients hospitalized with COPD exacerbation were consecutively included (n=598). Cases were classified into two categories: those with a history of TB and those without. Clinical, demographic, and radiological features were meticulously recorded and patients were followed up for mortality. 93 patients (15%) had past TB. On average, patients with a history of TB were four-year younger (p=0.002). Our study revealed that patients with TB history were diagnosed with COPD five-year earlier and died five-year earlier as compared to the patients without TB. In addition, in the TB history positive group, the rate of hospital admissions per year was higher compared to the group that lacked TB history (2.46±0.26 vs. 1.56±0.88; p=0.001). The patients with TB history had higher PaCO2 and lower FEV1 (p=0.008 and p=0.069 respectively). Median survival was 24 months for patients with past TB, and was 36 months for those without. Kaplan-Meier analysis revealed that although 3-year survival rate was lower in patients with TB history, it was not statistically significant (p=0.08). Cox regression analysis showed that while factors such as age, PaCO2, hematocrit, BMI and the Charlson index affected mortality rates in COPD patients (p<0.05), prior history of TB did not seem to have a significant impact on the mortality.

Our results showed that past TB caused more hospitalizations, lower respiratory functions and higher arterial carbon dioxide levels. It was found that, though the mortality rates were similar, COPD patients with past TB was diagnosed and died five-year earlier. We conclude that history of TB has an important role in natural course of COPD.