Table 2.
Characteristics of included patients (N = 12,803)
| Characteristic | Category | n (%) |
| Age range (y) | < 1 | 2063 (16.1) |
| 1 to < 5 | 2586 (20.2) | |
| 5 to < 15 | 900 (7.0) | |
| 15 to < 50 | 2452 (19.2) | |
| 50 to < 65 | 1425 (11.1) | |
| 65 to < 75 | 1241 (9.7) | |
| 75 to < 85 | 1255 (9.8) | |
| ≥85 | 881 (6.9) | |
| Sex | Female | 6269 (49.0) |
| Male | 6534 (51.0) | |
| Chronic conditions | 0 | 7506 (58.6) |
| 1 | 2499 (19.5) | |
| > 1 | 2798 (21.9) | |
| Pregnant a | Yes | 263 (2.1) |
| Hospitalized in the last 12 months b | Yes | 3417 (29.2) |
| Underlying chronic conditions | Cardiovascular disease | 3048 (23.8) |
| COPD | 1592 (12.4) | |
| Diabetes | 1490 (11.6) | |
| Renal disease | 745 (5.8) | |
| Neoplasms | 669 (5.2) | |
| Asthma | 655 (5.1) | |
| Neuromuscular disease | 487 (3.8) | |
| Immunological disorders | 392 (3.1) | |
| Autoimmune diseases | 230 (1.8) | |
| Cirrhosis | 206 (1.6) | |
| Rheumatological disease | 135 (1.1) | |
| Obesity c | Yes | 1300 (20.0) |
| Consultations with a general practitioner in the last 3 months | 0 | 4848 (43.8) |
| 1 | 2187 (19.7) | |
| > 1 | 4043 (36.5) | |
| Smoking habits d | Never smoker | 3583 (50.6) |
| Past smoker | 1953 (27.6) | |
| Current smoker | 1546 (21.8) | |
| Functional status impairment (Barthel score) e | Total (0–15) | 172 (5.5) |
| Severe (20–35) | 129 (4.1) | |
| Moderate (40–55) | 222 (7.1) | |
| Mild (60–90) | 831 (26.5) | |
| Minimal (95–100) | 1786 (56.9) | |
| Influenza vaccination ≥14 days from symptom onset | Yes | 1818 (14.2) |
| Antiviral use during the current episode | Yes | 2544 (19.9) |
Abbreviation: COPD Chronic obstructive pulmonary disease
a Proportion of females (N = 6269)
bN = 11,690
c Assessed for patients aged ≥18 years only, defined as a body mass index > 30 kg/m2, N = 6516
d Assessed for patients aged ≥18 years only, N = 7082
e Assessed for patients aged ≥65 years only, N = 3140