Table 1.
Clinical characteristics of patients with A (H1N1) pdm09 influenza pneumonia and seasonal influenza (H3N2) pneumonia
| Total (N = 88) | A (H1N1) pdm09 (n = 58) | A (H3N2) (n = 30) | P value | |
|---|---|---|---|---|
| Basic statistics | ||||
| Male | 48 (54.5%) | 34 (58.6%) | 14 (46.7%) | 0.29 |
| Age (years) | 52 ± 19 | 51 ± 20 | 53 ± 16 | 0.70 |
| Underlying diseases | 22 (25%) | 19 (32.8%) | 3 (10%) | 0.019 |
| COPD | 9 (10.2%) | 7 (12.1%) | 2 (6.7%) | 0.67 |
| Diabetes | 6 (6.8%) | 6 (10.3%) | 0 | – |
| Coronary heart diseases | 7 (8.0%) | 5 (8.6%) | 2 (6.7%) | 1.0 |
| Cerebrovascular diseases | 5 (5.7%) | 5 (8.6%) | 0 | – |
| Chronic heart diseases | 1 (1.1%) | 1 (1.7%) | 0 | – |
| Chronic renal diseases | 2 (2.3%) | 2 (3.4%) | 0 | – |
| Cirrhosis | 2 (2.3%) | 2 (3.4%) | 0 | – |
| Smoking history | 24 (27.3%) | 16 (27.6%) | 8 (26.7%) | 1.0 |
| Influenza vaccination within 1 year | 7 (8.0%) | 7 (12.1%) | 0 | – |
| Streptococcus pneumoniae vaccination within 1 year | 2 (2.3%) | 2 (3.4%) | 0 | – |
| Antibiotics before enrollment | 53 (60.2%) | 32 (55.2%) | 21 (70.0%) | 0.25 |
| Symptoms and signs on admission | ||||
| Fever | 85 (96.6%) | 57 (98.3%) | 28 (93.3%) | 0.55 |
| Tmax (°C) | 38.9 (38.8–39.1) | 38.9 (38.8–39.1) | 38.9 (38.6–39.3) | 0.65 |
| Cough | 85 (96.6%) | 56 (96.6%) | 29 (96.7%) | 1.0 |
| Expectoration | 72 (81.8%) | 47 (81.0%) | 25 (83.3%) | 1.0 |
| White sputum | 38 (53.5%) | 24 (52.2%) | 14 (56.0%) | 0.81 |
| Yellow sputum | 30 (42.3%) | 20 (43.5%) | 10 (40.0%) | 0.81 |
| Bloody sputum | 3 (4.2%) | 2 (4.3%) | 1 (4.0%) | 1.0 |
| Dyspnea | 25 (28.4%) | 17 (29.3%) | 8 (26.7%) | 0.81 |
| Chest pain | 9 (10.2%) | 7 (12.1%) | 2 (6.7%) | 0.67 |
| Nausea or vomiting | 6 (6.8%) | 3 (5.2%) | 3 (10.0%) | 0.69 |
| Headache or dizziness | 11 (12.5%) | 6 (10.3%) | 5 (16.7%) | 0.61 |
| Confusion | 0 | 0 | 0 | – |
| Respiratory rate (/min) | 20 (19.7–21.1) | 20 (19.8–21.7) | 20 (19.1–20.3) | 0.25 |
| Systemic blood pressure (mmHg) | 120 (119–125) | 120 (119–127) | 120 (116–126) | 0.90 |
| Conjunctival congestion | 3 (3.4%) | 2 (3.4%) | 1 (4.3%) | 1.0 |
| Moist rales | 38 (43.2%) | 25 (43.1%) | 13 (43.3%) | 1.0 |
| Dry rales | 20 (22.7%) | 17 (29.3%) | 3 (10.0%) | 0.06 |
| Skin rash | 1 (1.1%) | 1 (1.7%) | 0 | – |
| PSI score | 53.4 ± 26.2 | 56.0 ± 29.4 | 48.0 ± 17.2 | 0.13 |
| Laboratory findings on admission | ||||
| WBC (×109/L) | 6.9 ± 2.9 | 7.3 ± 2.9 | 6.4 ± 2.7 | 0.16 |
| Lymphocytes (×109/L) | 1.1 ± 0.5 | 1.1 ± 0.5 | 1.1 ± 0.5 | 0.74 |
| Hemoglobin (g/L) | 133.6 ± 19.5 | 132.7 ± 22.3 | 135.1 ± 13.2 | 0.58 |
| Platelet (×109/L) | 190.8 ± 70.2 | 189.9 ± 71.1 | 192.4 ± 69.8 | 0.87 |
| Abnormal ECG | 20 (22.7%) | 16 (27.6%) | 4 (13.3%) | 0.13 |
| ALT (U/L) | 21 (22.1–31.1) | 22 (22.5–35.7) | 18 (17.9–26.3) | 0.39 |
| AST (U/L) | 24.4 (25.2–33.8) | 27 (27.2–39.8) | 20 (19.5–25.0) | 0.006 |
| ALB (g/L) | 37.1 ± 5.9 | 35.3 ± 5.9 | 40.3 ± 4.1 | <0.001 |
| LDH (U/L) | 182.5 (187.3–219.6) | 201 (198.6–242.8) | 175 (154.6–189.5) | 0.018 |
| CK (U/L) | 90 (105.4–172.9) | 89 (110.2–191.2) | 91 (55.1–180.9) | 0.32 |
| Cr (μmol/L) | 71.1 ± 19.9 | 71.9 ± 19.5 | 71.6 ± 13.1 | 0.93 |
| ESR (mm/h) | 24.5 (9.8–43.5) | 25 (10.8–43.5) | 17 (5.5–47.5) | 0.26 |
| CRP (mg/L) | 14.6 (6.2–48) | 14.2 (6.0–50) | 15.4 (9.8–44.6) | 0.53 |
| Treatment and outcomes | ||||
| Hospitalization | 64 (72.7%) | 47 (81.0%) | 17 (56.7%) | 0.015 |
| ICU admission | 1 (1.1%) | 1 (1.7%) | 0/30 | – |
| Antiviral therapy | 15 (17.0%) | 15 (25.9%) | 0/30 | – |
| Antiviral within 48 h onset | 1 (1.1%) | 1 (1.7%) | 0 | – |
| Antibiotics after enrollment | 88 (100%) | 58 (100%) | 30 (100%) | – |
| Oxygen therapy | 38 (43.2%) | 27 (46.6%) | 11 (36.7%) | 0.49 |
| Noninvasive ventilation | 4 (4.5%) | 4 (6.9%) | 0 | – |
| Invasive ventilation | 1 (1.1%) | 1 (1.7%) | 0 | – |
| Vasoactivating agents | 2 (2.3%) | 1 (1.7%) | 1 (3.3%) | 1.0 |
| Secondary bacterial infections | 9 (14.3%) | 3 (7.7%) | 6 (25.0%) | 0.13 |
| Complications | ||||
| ARDS | 2 (2.3%) | 2 (3.4%) | 0 | – |
| Shock | 1 (1.1%) | 1 (1.7%) | 0 | – |
| Empyema | 0 | 0 | 0 | – |
| Acute renal failure | 0 | 0 | 0 | – |
| Duration of hospitalization (ds) | 7 (5–11) | 7 (5–11) | 8 (6–10) | 0.59 |
| Duration of fever (ds) | 5 (4–7) | 6 (4–8) | 4 (4–6) | 0.035 |
| Duration of cough (ds) | 15 (10–25) | 15 (10–27) | 15 (9.8–21) | 0.43 |
| Duration of sputum (ds) | 14 (9–23) | 15 (8.5–28) | 14 (9.3–20) | 0.59 |
| Duration of dyspnea (ds) | 8 (3–10.5) | 7.5 (3–10.3) | 8 (1–12) | 0.59 |
| Death | 1 (1.1%) | 1 (1.7%) | 0 | – |
Measurement data are displayed as mean ± standard deviation, or as median (interquartile rank) when data were not normally distributed, numeration data are presented in numbers (%).
COPD, chronic obstructive pulmonary disease; PST, pneumonia severity index; WBC, white blood cell; Hb, hemoglobin; ECG, electrocardiogram; ALT, alanine aminotransferase; AST, aspartate aminotransferase; ALB, albumin; LDH, lactase dehydrogenase; CK, creatinine kinase; Cr, creatinine; ESR, erythrocyte sedimentation rate; CRP, C-reactive protein; PT, prothrombin time; ARDS, acute respiratory distress syndrome; PSI, pneumonia severity index. Bold values indicate statistical significance.