Table 1.
Underlying conditions and clinical findings in patients with COVID-19 pneumonia observed in each wave at first examination.
| Variables | 1st to 3rd wave | 4th wave (Alpha variant) | 5th wave (Delta variant) |
|---|---|---|---|
| No. of patients | 502 | 338 | 301 |
| Median age (IQR), years | 65 (47–76) | 64 (51–74) | 50 (39–58) |
| No. of males/females | 312/190 | 229/109 | 169/132 |
| No. (%) of patients with comorbid illnesses | |||
| Diabetes mellitus | 104 (20.7) | 67 (19.8) | 45 (15.0) |
| Chronic lung disease | 57 (11.4) | 43 (12.7) | 28 (9.3) |
| Chronic heart disease | 41 (8.2) | 24 (7.1) | 12 (4.0) |
| Chronic renal disease | 32 (6.4) | 24 (7.1) | 5 (1.7) |
| Cerebrovascular disease | 33 (6.6) | 22 (6.5) | 11 (3.7) |
| Neoplastic disease | 31 (6.2) | 14 (4.1) | 11 (3.7) |
| Chronic liver disease | 15 (3.0) | 9 (2.7) | 10 (3.3) |
| Autoimmune disease | 15 (3.0) | 7 (2.1) | 5 (1.7) |
| No. (%) of patients with the following clinical signs and symptoms | |||
| Fever (≥37.0 °C) | 423 (84.3) | 298 (88.2) | 272 (90.4) |
| Cough | 253 (50.4) | 209 (61.8) | 225 (74.8) |
| Fatigue | 170 (33.9) | 112 (33.1) | 124 (41.2) |
| Shortness of breath | 139 (27.7) | 112 (33.1) | 87 (28.9) |
| Sore throat | 97 (19.3) | 68 (20.1) | 79 (26.2) |
| Loss of taste | 66 (13.1) | 55 (16.3) | 71 (23.6) |
| Anosmia | 54 (10.8) | 49 (14.5) | 71 (23.6) |
| Headache | 54 (10.8) | 33 (9.8) | 37 (12.3) |
| Diarrhea | 51 (10.2) | 27 (8.0) | 8 (2.7) |
| Sputum production | 49 (9.8) | 54 (16.0) | 55 (18.3) |
| Runny nose | 36 (7.2) | 24 (7.1) | 11 (3.7) |
| Joint pain | 28 (5.6) | 14 (4.1) | 20 (6.6) |
| Chest pain | 18 (3.6) | 5 (1.5) | 6 (2.0) |
| Nausea or vomiting | 17 (3.4) | 14 (4.1) | 11 (3.7) |
| Muscle ache | 17 (3.4) | 4 (1.2) | 11 (3.3) |
| Abdominal pain | 6 (1.2) | 1 (0.3) | 6 (2.0) |
| No. (%) of patients with pneumonia type | |||
| Community-acquired pneumonia | 422 (84.1) | 262 (77.5) | 274 (91.0) |
| Nursing and healthcare-associated pneumonia | 80 (15.9) | 76 (22.5) | 27 (9.0) |
| No. (%) of patients with each pneumonia severity score* | |||
| Mild (0 point) | 197 (39.2) | 57 (16.9) | 162 (53.8) |
| Moderate (1 or 2 points) | 239 (47.6) | 222 (65.7) | 124 (41.2) |
| Severe (3 points) | 52 (10.4) | 56 (16.6) | 12 (4.0) |
| Extremely severe (4 or 5 points) | 14 (2.8) | 3 (0.9) | 3 (1.0) |
| No. (%) of patients with COVID-19 severity score according to the criteria of Ministry of Health, Labour and Welfare | |||
| Moderate Ⅰ | 230 (45.8) | 112 (33.1) | 214 (71.1) |
| Moderate ⅠⅠ | 105 (20.9) | 58 (17.2) | 33 (11.0) |
| Severe | 167 (33.3) | 168 (49.7) | 54 (17.9) |
Continuous values are presented as medians and interquartile ranges (IQRs) and categorical/binary values as counts and percentages.