Table 2.
Incidence Rate Ratios for Admissions of COPD Patients by Primary Diagnosis During the Different Waves of the Pandemic Compared with the Prepandemic Period
| Phasea | AECOPD Admissions | Pneumonia Admissions | Total COPD Admissionsb | |||
|---|---|---|---|---|---|---|
| IRR (95% CI) | Pc | IRR (95% CI) | Pc | IRR (95% CI) | Pc | |
| First wave | 0.67 (0.58–0.77) | <0.001 | 0.61 (0.48–0.78) | <0.001 | 0.80 (0.71–0.89) | <0.001 |
| Intermediate period | 0.70 (0.58–0.84) | <0.001 | 0.47 (0.32–0.69) | <0.001 | 0.65 (0.56–0.77) | <0.001 |
| Second wave | 0.59 (0.52–0.68) | <0.001 | 0.35 (0.26–0.46) | <0.001 | 0.77 (0.69–0.85) | <0.001 |
| Third wave (Alpha) | 0.66 (0.55–0.79) | <0.001 | 0.43 (0.30–0.61) | <0.001 | 0.77 (0.67–0.89) | <0.001 |
| Fourth wave (Delta) | 0.90 (0.79–1.04) | 0.16 | 0.83 (0.65–1.06) | 0.15 | 0.89 (0.79–1.01) | 0.06 |
| Fifth wave (Omicron) | 0.69 (0.60–0.80) | <0.001 | 0.62 (0.48–0.80) | <0.001 | 0.78 (0.70–0.88) | <0.001 |
| Post-restriction period | 0.95 (0.84–1.08) | 0.42 | 0.86 (0.69–1.07) | 0.17 | 0.98 (0.88–1.09) | 0.70 |
Notes: Chronologically presented phases of the COVID-19 pandemic, compared to the corresponding prepandemic months. aDefinitions of the various phases of the pandemic are described in the methods section and Figure 1. bCombined outcome of all COPD admissions for AECOPD, pneumonia, influenza, or COVID-19. cp-values and incidence rate ratios with 95% confidence intervals were calculated using Poisson regression.
Abbreviations: AECOPD, acute exacerbation of chronic obstructive pulmonary disease; IRR, incidence rate ratio.