BACKGROUND Seasonal influenza can cause severe illness leading to intensive care unit (ICU) admission and death. OBJECTIVE To define the clinical and epidemiological features of severe seasonal influenza infection and factors associated with mortality. STUDY DESIGN A retrospective review was conducted on all patients with laboratory-confirmed influenza infection who were either admitted into the ICU or died in the two largest tertiary hospitals in Singapore from 2011-2015. RESULTS Of 520 patients included in our study, 423 (81.3%) had influenza A infection and the rest with influenza B. Of patients with influenza A infection, 70.0% (296/423) were subtyped, of whom 24.0% (71/296) had A/H1N1pdm2009 and 76.0% (225/296) had A/H3N2. The median age of patients was 72 years (IQR 61-82). Males constituted 53.1% (276/520). Median Charlson comorbidity index score was 1 (IQR 0-3). About 70% had physical or radiological evidence of pneumonia upon admission. In-hospital mortality was 58.1% (302/520). On multiple logistic regression analysis, factors positively associated with mortality were age ≥65 years (adjusted odds ratio, aOR = 3.64, 95%CI 2.21-5.99, p < 0.001), malignancy (aOR = 2.53, 95%CI 1.12-5.73; p = 0.026), and hypoalbuminemia (aOR = 2.16, 95%CI 1.26-3.73; p = 0.005), while antiviral therapy (aOR = 0.33, 95%CI 0.17-0.63; p < 0.001) and ventilation (aOR = 0.23, 95% CI 0.13-0.39; p < 0.001) were negatively associated. CONCLUSIONS Patients with severe seasonal influenza infection were characterized by advanced age, hypoalbuminemia and presence of pneumonia on admission. Age ≥65 years, malignancy, and hypoalbuminemia were associated with increased mortality, and antiviral therapy and ventilation with decreased mortality.

中文翻译：

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2011-2015年热带新加坡季节性流感相关重症监护病房的入院人数和死亡人数。

背景技术季节性流感可引起重症，导致重症监护病房（ICU）入院并死亡。目的确定严重季节性流感感染的临床和流行病学特征以及与死亡率相关的因素。研究设计回顾性回顾了2011-2015年间所有在实验室确认的流感感染的患者，这些患者要么被入住ICU，要么在新加坡两家最大的三级医院死亡。结果我们纳入研究的520名患者中，有423名（81.3％）患有甲型流感，其余为乙型流感。在甲型流感患者中，有70.0％（296/423）是亚型的，其中24.0％（71/296） ）具有A / H1N1pdm2009，而76.0％（225/296）具有A / H3N2。患者的中位年龄为72岁（IQR 61-82）。男性占53.1％（276/520）。Charlson合并症指数中位数为1（IQR 0-3）。入院时约有70％的人有肺炎的物理或放射学证据。住院死亡率为58.1％（302/520）。在多元逻辑回归分析中，与死亡率成正相关的因素是年龄≥65岁（校正比值比，aOR = 3.64，95％CI 2.21-5.99，p <0.001），恶性肿瘤（aOR = 2.53，95％CI 1.12-5.73； p = 0.026），低白蛋白血症（aOR = 2.16，95％CI 1.26-3.73； p = 0.005），抗病毒治疗（aOR = 0.33，95％CI 0.17-0.63； p <0.001）和通气（aOR = 0.23， 95％CI 0.13-0.39; p <0.001）呈负相关。结论严重季节性流感感染患者的特点是年龄高，低白蛋白血症和入院时存在肺炎。年龄≥65岁，恶性，