Table 2. Incidence Rate of Out-of-Hospital Cardiac Arrest (OHCA) During the 2020 Pandemic Period vs 2019, Overall and Stratified by County-Level Coronavirus Disease 2019 (COVID-19) Mortality Ratea.
| Variable | Unadjusted OHCA incidence, mean (SD), per 1 000 000 residents | Adjusted mean difference in incidence (95% CI) | P value | Incidence rate ratio | |
|---|---|---|---|---|---|
| 2020 | 2019 | ||||
| Overall | 88.5 (64.1) | 69.7 (49.8) | 14.8 (14.2-15.3) | <.001 | 1.21 |
| County-level COVID-19 mortality rate per million residents | |||||
| 0-25 | 86.7 (47.8) | 79.7 (43.8) | 4.3 (3.2-5.4) | <.001 | 1.05 |
| 26-100 | 64.1 (43.2) | 57.7 (41.5) | 6.9 (6.0-7.9) | <.001 | 1.12 |
| 101-250 | 111.6 (81.9) | 83.8 (63.3) | 22.0 (20.7-23.3) | <.001 | 1.26 |
| 251-500 | 121.0 (65.2) | 73.9 (49.8) | 38.6 (37.1-40.1) | <.001 | 1.52 |
| >500 | 90.9 (85.1) | 55.5 (57.2) | 28.7 (26.7-30.6) | <.001 | 1.52 |
a
The adjusted mean difference in OHCA incidence was derived from hierarchical linear regression models and therefore is not simply the difference in unadjusted OHCA incidence between 2020 and 2019.