Table 1.
Baseline characteristics of individuals with chronic obstructive pulmonary disease consulting or hospitalized for influenza-like illness according to the result of the influenza test.
| Laboratory-confirmed influenza cases n (%) |
Influenza-negative controls n (%) |
p value | |
|---|---|---|---|
| Total | 542 (100) | 1219 (100) | |
| Age groups (years) | 0.047 | ||
| 25–64 | 143 (26) | 261 (21) | |
| 65–84 | 313 (58) | 729 (60) | |
| ≥ 85 | 86 (16) | 229 (19) | |
| Sex | 0.029 | ||
| Male | 362 (67) | 877 (72) | |
| Female | 180 (33) | 342 (28) | |
| Healthcare setting | < 0.001 | ||
| Primary healthcare | 92 (17) | 72 (6) | |
| Hospital | 450 (83) | 1147 (94) | |
| Other major chronic conditions | |||
| Diabetes | 147 (27) | 395 (32) | 0.027 |
| Cancer | 148 (27) | 367 (30) | 0.233 |
| Liver cirrhosis | 34 (6) | 94 (8) | 0.283 |
| Renal disease | 91 (17) | 228 (19) | 0.336 |
| Immunodeficiency | 16 (3) | 32 (3) | 0.697 |
| Asthma | 50 (9) | 90 (7) | 0.187 |
| Cardiovascular disease | 180 (33) | 483 (40) | 0.010 |
| Dementia | 10 (2) | 38 (3) | 0.130 |
| Stroke | 38 (7) | 95 (8) | 0.566 |
| Rheumatic disease | 19 (4) | 33 (3) | 0.361 |
| Severe obesity | 25 (5) | 50 (4) | 0.624 |
| Vaccination in the current season | < 0.001 | ||
| No | 233 (43) | 387 (32) | |
| Yes | 309 (57) | 832 (68) | |
| Influenza vaccines in the 5 prior seasons | < 0.001 | ||
| 0 | 166 (31) | 251 (21) | |
| 1–2 | 69 (13) | 146 (12) | |
| 3–5 | 307 (56) | 822 (67) | |
| Influenza season | < 0.001 | ||
| 2015–2016 | 80 (14) | 150 (12) | |
| 2016–2017 | 102 (19) | 181 (15) | |
| 2017–2018 | 161 (30) | 242 (20) | |
| 2018–2019 | 123 (23) | 288 (24) | |
| 2019–2020 | 76 (14) | 358 (29) | |