3.3. The effects of asthma-related respiratory comorbidities on mortality in the asthma cohort compared with the control cohort
As shown in Table 2 , the relative risk of mortality in asthmatic patients without COPD (adjusted HR, aHR = 0.95, 95% CI = 0.90–1.01) or pneumonia (aHR = 0.98, 95% CI = 0.98–1.09) compared with the controls was not significantly increased; however, asthmatic patients with COPD (aHR = 1.49, 95% CI = 1.39–1.59) or pneumonia (aHR = 1.59, 95% CI = 1.46–1.74) had increased risk of mortality compared with the controls (aHR = 1.49, 95% CI = 1.39–1.59), which is in agreement with survival analyses (COPD in Figure 3A and pneumonia in Figure 3B) .
Regardless of the presence or absence of bronchiectasis or lung cancer, asthmatic patients had an increased risk of mortality compared with the controls. The presence of bronchiectasis (aHR = 1.43, 95% CI = 1.18–1.73) or lung cancer (aHR = 4.11, 95% CI = 2.59–6.52) tended to further increase the risk of all-cause mortality in the asthmatic cohort compared with the control cohort (bronchiectasis in Figure 3C and lung cancer in Figure 3D ). Although the risk of mortality was increased in asthmatic patients without NTM infection (aHR = 1.13, 95% CI = 1.08–1.18) compared with subjects without asthma, there was no significant increased risk of mortality in asthmatic patients without NTM infection compared with subjects without asthma (aHR = 0.85, 95% CI = 0.12–6.00; Figure 3E ).
Except for lung cancer, patients in the asthma cohort had a higher risk of respiratory mortality compared with subjects in the control cohort regardless of respiratory comorbidities. The presence of these respiratory comorbidities tended to further increase the risk of respiratory mortality in the asthmatic cohort compared with the control cohort (Table 2 ).