Proportion of missing and unknown data (N (%)) in the EULAR COVID-19 registry as of 1 March 2021
| Variable description | Total N=5824 | |
| Unknown | Missing | |
| General | ||
| Date of case report | N/A | 2 (0.03) |
| Age | N/A | 0 |
| Biological sex | N/A | 0 |
| Race/ethnic origin | 209 (3.59) | 1751 (30.07) |
| Comorbidities | 92 (1.58) | 250 (4.29) |
| Smoking status | 1435 (24.64) | 709 (12.17) |
| E-cigarette/vaping status | 1649 (28.31) | 1708 (29.33) |
| Seasonal influenza vaccination | 1552 (26.65) | 2399 (41.19) |
| Availability of lab tests | 353 (6.06) | 2366 (40.63) |
| COVID-19 measures | ||
| Date of COVID-19 diagnosis | 0 | 2 (0.03) |
| Method of COVID-19 diagnosis | 168 (2.88) | 27 (0.46) |
| COVID-19 diagnosis location | 844 (14.49) | 1636 (28.09) |
| COVID-19 infection acquisition | 1394 (23.94) | 1716 (29.46) |
| COVID-19 clinical symptoms * | 53 (1.03) | 61 (1.18) |
| COVID-19 treatment | 139 (2.39) | 1315 (22.58) |
| COVID-19 complications | 188 (3.23) | 2368 (40.66) |
| COVID-19 outcome | ||
| COVID-19 outcome | 203 (3.49) | 2 (0.03) |
| Hospitalised | 19 (0.33) | 144 (2.47) |
| Interventions in hospital * | 52 (2.63) | 532 (26.90) |
| Approximate number of days from COVID-19 symptom onset to death* | N/A | 111 (25.52) |
| Approximate number of days from COVID-19 symptom onset to resolution* | N/A | 1506 (31.12) |
| Rheumatic disease | ||
| Rheumatic disease diagnosis | 0 | 0 |
| Rheumatic disease activity | 218 (3.74) | 1592 (27.34) |
| Medication | ||
| Immunomodulatory medication for rheumatic disease | 21 (0.36) | 307 (5.27) |
| Glucocorticoids at time of COVID-19 diagnosis | 50 (0.86) | 40 (0.69) |
| Glucocorticoid dose* | N/A | 75 (4.23) |
| PD5 inhibitors | 153 (2.63) | 1994 (34.24) |
| ACE inhibitors | 198 (3.40) | 1887 (32.40) |
| Angiotensin receptor blockers | 202 (3.47) | 1925 (33.05) |
| Selective NSAIDs | 212 (3.64) | 1879 (32.26) |
| Non-selective NSAIDs | 227 (3.90) | 1412 (24.24) |
Data are N (%) for all variables.
*Variable adjusted for database logic.
ACE, Angiotensin-converting enzyme; COVID-19, Coronavirus Disease 2019; EULAR, European Alliance of Associations of Rheumatology; NSAIDs, non-steroidal anti-inflammatory drugs; PD5, phosphodiesterase 5.