Table 1.
Basic characteristics of patients who met the inclusion criteria
| Case (n = 2532) | Control (n = 5122) | Total (n = 7654) | P valuea | |
|---|---|---|---|---|
| Age | 68 [56–78] | 66 [54–79] | 67 [55–79] | < 0.001 |
| Male | 1495 (59.1%) | 2510 (49.0%) | 4005 (52.3%) | < 0.001 |
| Cardiovascular disease | 196 (7.7%) | 373 (7.3%) | 569 (7.4%) | 0.501 |
| Respiratory disease | 130 (5.1%) | 159 (3.1%) | 289 (3.8%) | < 0.001 |
| Diabetes mellitus | 580 (22.9%) | 891 (17.4%) | 1,471 (19.2%) | < 0.001 |
| Severe renal disease or dialysis | 101 (4.0%) | 92 (1.8%) | 193 (2.5%) | < 0.001 |
| Hypertension | 1079 (42.6%) | 1939 (37.9%) | 3018 (39.4%) | < 0.001 |
| Obesity | 201 (7.7%) | 296 (5.8%) | 490 (6.4%) | < 0.001 |
| Charlson comorbidity index | 0 [0–1] | 0 [0–1] | 0 [0–1] | < 0.001 |
| NEWS at day 1 | 1 [0–2] | 1 [0–2] | 1 [0–2] | < 0.001 |
| NEWS at day 4 | 1 [0–3] | 1 [0–2] | 1 [0–3] | < 0.001 |
| NEWS at day 8 | 1 [0–3] | 1 [0–2] | 1 [0–3] | < 0.001 |
| NEWS at day 15 | 1 [0–3] | 1 [0–3] | 1 [0–3] | 0.336 |
| NEWS at day 22 | 2 [0–4] | 1 [0–3] | 1 [0–3] | 0.416 |
| NEWS at day 29 | 9.5 [9–11] | 9 [9–11] | 9 [9–11] | 0.519 |
| Fatal cases | 173 (6.8%) | 165 (3.2%) | 338 (4.4%) | < 0.001 |
| Oxygen administration during hospitalizationb | 1066 (42.1%) | 1071 (20.9%) | 2137 (27.9%) | < 0.001 |
| IMV/ECMO during hospitalization | 91 (3.6%) | 44 (0.9%) | 135 (1.8%) | < 0.001 |
| Days from symptom onset to hospitalization | 3 [1–4] | 3 [1–4] | 3 [1–4] | 0.172 |
| Systemic steroid use | 1243 (49.1%) | 984 (19.2%) | 2227 (29.1%) | < 0.001 |
| Remdesivir use | 244 (9.6%) | 520 (10.2%) | 764 (10.0%) | 0.500 |
| Tocilizumab use | 96 (3.8%) | 32 (0.6%) | 128 (1.7%) | < 0.001 |
| Baricitinib use | 0 (0%) | 0 (0%) | 0 (0%) | 1.0 |
| Days from onset to favipiravir administration | 4 [2–5] | NA | NA | NA |
| Days from admission to favipiravir administration | 1 [0–3] | NA | NA | NA |
| Ten-day or longer duration of favipiravir administration | 1358 (54.1%) | NA | NA | NA |
Numbers in the brackets represent percentage and interquartile range
NA not available, NEWS National Early Warning Score, IMV/ECMO invasive mechanical ventilation/extracorporeal membrane oxygenation
aResults of the Mann–Whitney U test for continuous variables and chi-square test for categorical variables (comparison between case group and control group)
bIndication for supplementary oxygen was judged by each physician