Table 2. Annual Age-, Sex-, and Race-Specific Incidence Rate of Chilblains and COVID-19 Before and During the Pandemic.
| Variable | 2020 Denominator | Chilblains incidence per 100 000 person-years | COVID-19 incidence per 1000 person-years (March-November 2020) | ||||
|---|---|---|---|---|---|---|---|
| Before the pandemic (April-December, 2016-2019) | During the pandemic (April-December, 2020) | ||||||
| No. of cases | Incidence rate (95% CI)a | No. of cases | Incidence rate (95% CI)a | No. of cases | Incidence rate (95% CI)a | ||
| Overall | 4 370 992 | 539 | 5.2 (4.8-5.6) | 780 | 28.6 (26.8-30.4) | 78 129 | 28.6 (28.4-28.8) |
| Age, y | |||||||
| 0-12 | 603 032 | 46 | 3.7 (2.9-4.9) | 103 | 27.3 (22.9-32.6) | 6315 | 16.8 (16.4-17.1) |
| 13-19 | 354 595 | 78 | 9.1 (7.5-11.2) | 139 | 62.7 (53.9-73.0) | 5697 | 25.7 (25.1-26.3) |
| 20-39 | 1 249 917 | 128 | 4.4 (3.8-5.2) | 217 | 27.8 (24.6-31.4) | 29 483 | 37.7 (37.3-38.1) |
| 40-59 | 1 199 361 | 99 | 3.4 (2.9-4.1) | 164 | 21.9 (19.0-25.2) | 25 279 | 33.7 (33.3-34.1) |
| ≥60 | 964 087 | 188 | 7.5 (6.6-8.6) | 157 | 26.1 (22.6-30.1) | 11 355 | 18.8 (18.5-19.2) |
| Sexb | |||||||
| Female | 2 241 618 | 370 | 7.0 (6.3-7.6) | 464 | 33.1 (30.5-36.0) | 40 923 | 29.2 (29.0-29.5) |
| Male | 2 129 374 | 169 | 3.3 (2.9-3.8) | 316 | 23.7 (21.5-26.3) | 37 206 | 28.0 (27.7-28.2) |
| Race/ethnicity | |||||||
| African American | 276 448 | 28 | 4.1 (2.9-5.7) | 20 | 11.6 (7.8-17.3) | 5040 | 29.2 (28.4-29.9) |
| Asian American | 855 125 | 118 | 5.8 (4.9-6.9) | 227 | 42.5 (37.7-47.8) | 10 131 | 19.0 (18.6-19.3) |
| Latinx | 922 117 | 69 | 3.1 (2.5-3.9) | 72 | 12.5 (10.1-15.4) | 36 005 | 62.5 (61.9-63.1) |
| White | 1 734 060 | 289 | 6.6 (5.9-7.3) | 387 | 35.7 (32.6-39.1) | 19 439 | 17.9 (17.7-18.2) |
| Other | 583 242 | 35 | 3.3 (2.4-4.5) | 74 | 20.3 (16.5-25.0) | 7514 | 20.6 (20.2-21.0) |
a
Denominators for prepandemic period based on January 1, 2018, enrollment and for pandemic period based on June 1, 2020, enrollment.
b
The number of patients who were nonbinary or transgender was too few to analyze. All differences between incidence rates were significant at P < .001.