[Clinical characteristics and prognosis analysis of 37 patients with severe influenza]

To explore the clinical characteristics and prognostic risk factors of severe influenza.

Clinical data of severe influenza patients admitted to the department of respiratory and critical care medicine of the Second Affiliated Hospital of Anhui Medical University from March 2014 to June 2019 were retrospectively analyzed. General information, laboratory test results, and etiological test results of the hospitalization outcomes for survival group and death group during the 28-day follow-up were analyzed using Logistic regression analysis.

Among the 37 patients, 29 were males and 8 were females. They aged 25-86 years old with an average of (59.59±15.16) years old. Twenty-one cases had chronic underlying diseases; 28 cases had co-infections, including 6 cases with bacterial infections, 7 cases with fungal infections, 3 case with other pathogens, and 12 cases with mixed infection. Among the 37 patients, 9 died during hospitalization and 5 died within 28-day of discharge. The overall mortality rate was 37.84%. Compared with the survival group, patients in the death group were older (years old: 66.57±3.94 vs. 55.35±14.53), British Thoracic Society's modified pneumonia score (CURB-65 score), acute physiology and chronic health evaluation II (APACHE II) score, neutrophil count, D-dimer, 48-hour C-reactive protein (CRP) and procalcitonin (PCT) were higher [CURB-65 score: 2 (2, 3) vs. 1 (0, 2), APACHE II: 16.00±4.62 vs. 11.00±4.22, neutrophil count (×10⁹/L): 8.87 (5.42, 11.33) vs. 3.58 (2.55, 7.13), D-dimer (mg/L): 7.97 (5.19, 12.68) vs. 2.91 (1.19, 5.02), 48-hour CRP (mg/L): 127.83±92.24 vs. 87.01±57.00, 48-hour PCT (μg/L): 1.79 (0.59, 4.44) vs. 0.37 (0.13, 0.99)], oxygenation index (PaO₂/FiO₂) and creatinine clearance rate were lower [PaO₂/FiO₂ (mmHg, 1 mmHg = 0.133 kPa): 109.52±49.30 vs. 204.82±67.61, creatinine clearance rate (mL×min^-1×1.73 m^-2): 55.49±21.23 vs. 77.59±29.73], and the differences were statistically significant (all P < 0.05). There was no significant difference in gender, combined chronic underlying diseases, lymphocyte count, albumin, lactate dehydrogenase (LDH), prothrombin time (PT), activated partial thromboplastin time (APTT), fibrinogen (Fib), 24-hour CRP and PCT between the two groups. A total of 37 pathogens were cultured, including 17 Gram-negative bacteria (45.95%), 3 Gram-positive bacteria (8.10%), and 17 fungi (45.95%). The number of Acinetobacter baumannii infections in the death group was significantly higher than that in the survival group (cases: 7 vs. 2, P < 0.05). Logistic regression analysis showed that age, CURB-65 score, APACHE II score, PaO₂/FiO₂, neutrophil count, creatinine clearance rate, combined Acinetobacter baumannii infection, deep vein catheterization, catheterization, and stomach preservation during hospitalization were risk factors for the prognosis of patients with severe influenza [hazard ratios (HR) were 1.064, 4.920, 1.286, 0.975, 1.286, 0.965, 0.095, 0.083, 9.333, 0.089, respectively, all P < 0.05]. Multivariate analysis showed that low PaO₂/FiO₂ and Acinetobacter baumannii infection were risk factors for prognosis of severe influenza (HR were 0.834 and 0.000, respectively, both P < 0.05).

Old age, high CURB-65 score, high APACHE II score, and co-infection are risk factors for the prognosis of patients with severe influenza.