Post-Inhaled Corticosteroid Pulmonary Tuberculosis Increases Lung Cancer in Patients with Asthma

PURPOSE: To evaluate the association between post-inhaled corticosteroid (ICS) pulmonary tuberculosis (TB), pneumonia and lung cancer in patients with asthma. METHODS: The study samples were collected from the National Health Insurance Database. Asthmatic patients who were first-time users of ICS between 2003 and 2005 were identified as cases. For each case, 4 control individuals were randomly matched for sex, age and date of ICS use. Cases and matched controls were followed up until the end of 2010. Cox proportional hazard regression was used to determine the hazard ratio for pulmonary infections and lung cancer risk in the ICS users and non-users. RESULTS: A total of 10,904 first-time users of ICS were matched with 43,616 controls. The hazard ratios for lung cancer were: 2.52 (95% confidence interval [CI], 1.22–5.22; p = 0.012) for individuals with post-ICS TB, 1.28 (95%CI, 0.73–2.26; p = 0.389) for post-ICS pneumonia, 2.31(95%CI, 0.84–6.38; p = 0.105) for post-ICS pneumonia+TB, 1.08 (95%CI, 0.57–2.03; p = 0.815) for TB, 0.99 (95%CI, 0.63–1.55; p = 0.970) for pneumonia, and 0.32 (95%CI, 0.05–2.32; p = 0.261) for pneumonia+ TB, respectively. CONCLUSIONS: Post-ICS TB increased lung cancer risk in patients with asthma. Because of the high mortality associated with lung cancer, screening tests are recommended for patients with post-ICS TB.