Table 1.
Baseline characteristics of participants at admission to a hospital in Japan for COVID-19 or influenza.
| COVID-19 (n=16,790) | Influenza (n=27,870) | p | |
|---|---|---|---|
| Age, median (IQR), year | 64 (40–80) | 67 (5–84) | <0·0001 |
| Sex (women), n (%) | 7,242 (43·1) | 13,039 (46·8) | <0·0001 |
| Calendar year, n (%) | |||
| 2017 | − | 6,491 (23·3) | |
| 2018 | − | 7,943 (28·5) | |
| 2019 | − | 10,170 (36·5) | |
| 2020 | 16,790 (100) | 3,266 (11·7) | |
| BMI, n (%), kg/m2 | <0·0001 | ||
| <25 | 10,563 (62·9) | 19,492 (69·9) | |
| 25 to <30 | 2,601 (15·5) | 2,645 (9·5) | |
| 30≤ | 910 (5·4) | 740 (2·7) | |
| Missing | 2,716 (16·2) | 4,993 (17·9) | |
| Smoking history, n (%) | <0·0001 | ||
| Yes | 4,473 (26·6) | 3,665 (13·2) | |
| No | 9,487 (56·5) | 21,966 (78·8) | |
| Missing | 2,830 (16·9) | 2,239 (8·0) | |
| Comorbidities, n (%) | |||
| Cancer | 2,149 (12·8) | 2,385 (8·6) | <0·0001 |
| Chronic lung disease | 3,008 (17·9) | 8,067 (29·0) | <0·0001 |
| Ischemic heart disease | 1,436 (8·6) | 6,712 (24·1) | <0·0001 |
| Heart failure | 2,517 (15·0) | 4,246 (15·2) | 0·49 |
| Arrhythmia | 1,608 (9·6) | 2,831 (10·2) | 0·047 |
| Hypertension | 5,192 (30·9) | 7,965 (28·6) | <0·0001 |
| Diabetes mellitus | 3,602 (21·5) | 4,804 (17·2) | <0·0001 |
| Cerebrovascular disease | 1,739 (10·4) | 3,659 (13·1) | <0·0001 |
| Chronic kidney disease | 1,048 (6·2) | 1,507 (5·4) | <0·0001 |
| End-stage renal disease | 690 (4·1) | 803 (2·9) | <0·0001 |
| Dementia | 1,522 (9·1) | 3,064 (11·0) | <0·0001 |
| Dyslipidaemia | 2,759 (16·4) | 4,052 (14·5) | <0·0001 |
| Cirrhosis | 230 (1·4) | 252 (0·9) | <0·0001 |
| Deficiency anaemia | 1,652 (9·8) | 2,165 (7·8) | <0·0001 |
| Peripheral artery disease | 233 (1·4) | 435 (1·6) | 0·14 |
Abbreviations: BMI, body mass index; IQR, interquartile range. Data are reported as number (%) for categorical variables and median (IQR) for continuous variables. We conducted Student's t-test or the Mann-Whitney U test for continuous variables and the χ2 test for categorical variables.