Table 2.
Unadjusted and adjusted associations between aspirin use and severity of acute exacerbation of chronic obstructive pulmonary disease
| Outcomes | Aspirin users | Non-users | Unadjusted association (95% CI) | P-value | Adjusted association (95% CI) | P-value |
|---|---|---|---|---|---|---|
| Main analysis | ||||||
| In-hospital deatha | 1.0% (0.8–1.1%) | 1.4% (1.4–1.5%) | 0.67 (0.56–0.80) | <0.001 | 0.60 (0.50–0.72) | <0.001 |
| Invasive mechanical ventilationa | 1.7% (1.5–1.9%) | 2.6% (2.5–2.6%) | 0.64 (0.56–0.74) | <0.001 | 0.64 (0.55–0.73) | <0.001 |
| NIPPV usea | 7.6% (7.2–8.1%) | 7.2% (7.1–7.3%) | 1.06 (0.99–1.13) | 0.06 | 1.05 (0.98–1.12) | 0.20 |
| Hospital LOS, days, median (IQR)b | 3 (2–5) | 4 (2–6) | −6% (−4 to −7%) | <0.001 | −7% (−5 to −9%) | <0.001 |
| Sensitivity analysis 1c | ||||||
| In-hospital deatha | 1.0% (0.8–1.3%) | 1.3% (1.1–1.3%) | 0.85 (0.67–1.09) | 0.20 | 0.72 (0.56–0.93) | 0.01 |
| Invasive mechanical ventilationa | 1.8% (1.5–2.1%) | 2.4% (2.3–2.5%) | 0.74 (0.61–0.89) | 0.002 | 0.71 (0.59–0.87) | 0.001 |
| NIPPV usea | 8.0% (7.3–8.7%) | 7.1% (7.0–7.2%) | 1.15 (1.05–1.27) | 0.002 | 1.10 (0.99–1.21) | 0.053 |
| Hospital LOS, days, median (IQR)b | 3 (2–5) | 3 (2–5) | −2% (0 to −5%) | 0.10 | −5% (−2 to −8%) | <0.001 |
| Sensitivity analysis 2d | ||||||
| In-hospital deatha | 0.8% (0.6–1.1%) | 1.0% (1.0–1.1%) | 0.81 (0.59–1.11) | 0.19 | 0.66 (0.47–0.92) | 0.02 |
| Invasive mechanical ventilationa | 1.8% (1.5–2.2%) | 2.4% (2.3–2.5%) | 0.79 (0.64–0.97) | 0.02 | 0.77 (0.62–0.95) | 0.02 |
| NIPPV usea | 7.2% (6.5–7.9%) | 6.2% (6.1–6.4%) | 1.20 (1.08–1.34) | 0.001 | 1.15 (1.03–1.29) | 0.02 |
| Hospital LOS, days, median (IQR)b | 3 (2–5) | 3 (2–5) | −1% (−4 to −2%) | 0.52 | −4% (−7 to −1%) | 0.02 |
CI confidence interval, NIPPV non-invasive positive pressure ventilation, IQR interquartile range
aOdds ratio of aspirin use for each outcome in comparison with non-aspirin use, by using logistic regression model with generalized estimating equation to account for patient clustering within hospitals
bPercent change in hospital LOS, by using negative binomial model with generalized estimating equation to account for patient clustering within hospitals
cAmong patients without coronary artery diseases or ischemic stroke, 6753 patients were aspirin users and 136,325 patients were non-users
dAmong patients without coronary artery diseases, ischemic stroke, or heart failure, 5257 patients were aspirin users and 114,425 patients were non-users