ABSTRACT
Background: Asthmatic patients are generally considered to have
an increased risk of mortality compared with subjects without asthma.
However, this issue has not been fully evaluated using nationally
representative data. In addition, it is unclear whether respiratory
comorbidities other than chronic obstructive pulmonary disease (COPD)
are associated with increased mortality in asthmatic patients compared
with subjects without asthma.
Methods: Using a nationally representative sample database, we
performed a retrospective cohort study of patients with asthma and age-
sex-matched control cohort. We estimated hazard ratio (HR) and 95%
confidence interval (CI) for mortality. We also stratified the asthma
cohort based on respiratory comorbidities.
Results: During a
median 8.9-year follow-up, the overall mortality rate was higher in the
asthma cohort than in the control cohort (p < 0.001). The HR
for mortality in the asthma cohort compared with the control cohort was
1.13 (95% CI = 1.07–1.19). The effects of asthma on mortality were
more evident in males, patients under medical aid, and subjects with
COPD. Respiratory comorbidities were significantly associated with
increased risk of mortality in asthmatic patients compared with controls
(COPD, adjusted HR, aHR = 1.49, 95% CI = 1.39–1.59; bronchiectasis,
aHR = 1.43, 95% CI = 1.18–1.73; lung cancer, aHR = 4.11, 95% CI =
2.59–6.52; pneumonia, aHR = 1.59, 95% CI = 1.46–1.74).
Conclusion: Patients with asthma had a higher mortality rate
compared with subjects without asthma. Coexisting pulmonary
comorbidities were the primary cause of higher mortality in patients
with asthma
Keywords: asthma, mortality, respiratory comorbidities