Table 1.
Baseline demographic and clinical characteristics of patients with influenza infection
| Characteristics | All patients (n = 239) | Ct value (viral load) | P valuea | P valueb | ||
|---|---|---|---|---|---|---|
| ≤ 20 (n = 27) | > 20–30 (n = 138) | > 30 (n = 74) | ||||
| Age (years) | 67.08 ± 16.09 | 70.11 ± 15.91 | 66.13 ± 16.56 | 67.72 ± 15.29 | 0.46 | 0.21 |
| Sex (male) | 142 (59.7%) | 18 (66.7%) | 78 (56.9%) | 46 (62.2%) | 0.55 | 0.41 |
| Charlson comorbidity index score | 2 (1–4) | 2 (0.25–3.75) | 2 (1–4) | 2 (1–3) | 0.58 | 0.33 |
| Previous comorbid conditions | ||||||
| Active smoker | 48 (20.1%) | 5 (18.5%) | 29 (21%) | 14 (18.9%) | 0.91 | 0.82 |
| Obesity | 43 (18%) | 6 (22.2%) | 24 (17.4%) | 13 (17.6%) | 0.83 | 0.59 |
| Asthma | 15 (6.3%) | 1 (3.7%) | 10 (7.2%) | 4 (5.4%) | 0.73 | 1 |
| COPD | 51 (21.3%) | 5 (18.5%) | 33 (23.9%) | 13 (17.6%) | 0.52 | 0.7 |
| Cardiovascular disease | 68 (28.5%) | 6 (22.2%) | 38 (27.5%) | 24 (32.4%) | 0.56 | 0.44 |
| Immunosuppression (including steroids)* | 53 (22.2%) | 3 (11.1%) | 34 (24.6%) | 16 (21.6%) | 0.29 | 0.14 |
| Influenza vaccination (last year) | 96 (40.3%) | 10 (37%) | 50 (36.5%) | 36 (48.6%) | 0.21 | 0.71 |
| Influenza A H1N1pdm09 (vs influenza B) | 207 (86.6%) | 27 (100%) | 125 (90.6%) | 55 (74.3%) | < 0.001 | 0.031 |
| Duration of illness prior to confirming the infection (days) | 3 (2–5) | 3 (1–7) | 3 (2–4.75) | 3.5 (2–5) | 0.114 | 0.54 |
| Clinical findings at admission | ||||||
| Temperature (°C) | 37.62 ± 1.02 | 37.9 ± 0.9 | 37.58 ± 0.99 | 37.60 ± 1.11 | 0.39 | 0.17 |
| Dyspnea | 142 (59.4%) | 18 (66.7%) | 88 (63.8%) | 36 (48.6%) | 0.073 | 0.41 |
| Respiratory rate | 19.95 ± 7.97 | 23.83 ± 11.66 | 19.38 ± 7.41 | 20.26 ± 8.29 | 0.71 | 0.45 |
| SpO2 (%) | 91.28 ± 5.95 | 90.92 ± 4.72 | 91.47 ± 5.1 | 91.04 ± 5.13 | 0.59 | 0.52 |
| Bronchospasm | 102 (42.7%) | 9 (33.3%) | 54 (39.1%) | 39 (52.7%) | 0.095 | 0.29 |
| Chest X-ray abnormal findings | 113 (50.2%) | 20 (76.9%) | 61 (46.9%) | 32 (46.4%) | 0.015 | 0.004 |
| Treatment | ||||||
| Oseltamivir | 231 (96.7%) | 27 (100%) | 134 (97.1%) | 70 (94.6%) | 0.37 | 0.6 |
| Empiric antibiotic therapy | 174 (72.8%) | 17 (63%) | 103 (74.6%) | 54 (73%) | 0.45 | 0.22 |
| Pathogen directed antibiotic therapy | 17 (7.1%) | 3 (11.1%) | 9 (6.5%) | 5 (6.8%) | 0.69 | 0.41 |
| Treatment with steroids | 136 (56.9%) | 17 (63%) | 76 (55.1%) | 43 (58.1%) | 0.72 | 0.32 |
Results are expressed as mean ± standard deviation or median with interquartile range (IQR) or as absolute value (percentage). *Immunosuppression was defined as the presence of any the following: active malignant neoplasia, autoimmune disease, solid organ transplantation, HIV infection, use of steroids or chemotherapy. Use of steroids was defined as (1) more than 20 mg/day of oral prednisone during 7 days or longer or (2) less than 20 mg/day during a minimum of 3 months. COPD chronic obstructive pulmonary disease. aAcross all Ct value groups. bBetween high viral load group (Ct ≤ 20) and other groups combined. Bold font means significant differences between variables