3.2. Mortality
During a median 8.9-year follow-up duration, the overall mortality rate
was 1,312/100,000 PY in the asthma cohort and 1,174/100,000 PY in the
control cohort (p < 0.001), which is consistent with survival
analysis (p < 0.01 for a log-rank test; Figure
1 ). Patients in the asthma cohort had a significantly higher all-cause
mortality rate than subjects in the control cohort (HR = 1.13, 95% CI =
1.07–1.19). As shown in Figure 2A , a positive association
between asthma and all-cause mortality was observed in both age groups.
However, the association was only significant in males, patients who
received medical aid, patients with COPD, patients without
bronchiectasis, and patients without pneumonia. The association was
stronger in males than females (p for interaction = 0.004), in patients
who received medical aid than in patients who received other medical
insurance, and in patients with COPD than in patients without COPD (p
for interaction = 0.003)
The HR for respiratory mortality was 2.63 (95% CI = 2.28–3.03). As
shown in Figure 2B , the positive association between asthma and
respiratory mortality was consistent in all subgroups. The association
was stronger in males than females (p for interaction = 0.043) and in
younger patients (age < 60 years) than older patients (age\(\geq\ \)60 years; p for interaction = 0.005).