Introduction Influenza virus causes significant global annual morbidity and mortality. Thrombocytopenia is recognized as a poor prognostic factor in sepsis and is associated with mortality, while lymphopenia has been established as a poor prognostic factor in other viral infections. We aimed to assess the incidence of thrombocytopenia and lymphopenia in seasonal influenza and their effect on clinical outcomes. Methods This single-center, retrospective, cohort study included consecutive adult patients, hospitalized in Rabin Medical Center between October 2017 - April 2018, with laboratory confirmed influenza. Patients were grouped according to blood counts on admission: 1. Thrombocytopenia (<150 K/ml), 2. lymphopenia (<0.5K/ml), and 3. both thrombocytopenia and lymphopenia. Patients without thrombocytopenia and lymphopenia were designated as controls. The primary outcome was 30-days all-cause mortality. Risk factors were identified by univariable and multivariable analyses, using logistic regression and reported as odds ratios (OR) and 95% confidence intervals (CI). Results A total of 625 patients were included, 112 (18%) had thrombocytopenia, 98 (15.6%) had lymphopenia and 107 (17%) had both. The crude 30-days all-cause mortality was 7.6% (48/625). Mortality rates were 7.1% (8/112) for the thrombocytopenia group, 11.2% (11/98) for the lymphopenia group, and 14.9% (16/107) for patients with both vs 4.2% (13/308) in the control (p=0.000 for all). In a multivariable regression model, significant thrombocytopenia (<100 K/microL) [OR 5.07, (95% CI 1.5-16.2)[, age [OR 1.07, (95% CI 1.02-1.11)], time to oseltamivir ]OR 1.006, (95%1.002-1.11)], and significant respiratory support [OR 8.85, (3.4-22.6)], were associated with 30-day all-cause mortality. Conclusion Patients hospitalized with seasonal influenza and thrombocytopenia < 100K/mL on admission, have an increased 30-days all-cause mortality.

中文翻译：

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血小板减少症和淋巴细胞减少症对流感病毒感染患者死亡率的影响——一项回顾性队列研究。

简介 流感病毒导致全球每年显着的发病率和死亡率。血小板减少症被认为是败血症的不良预后因素，并与死亡率相关，而淋巴细胞减少症已被确定为其他病毒感染的不良预后因素。我们的目的是评估季节性流感中血小板减少症和淋巴细胞减少症的发生率及其对临床结果的影响。方法 这项单中心、回顾性、队列研究纳入了 2017 年 10 月至 2018 年 4 月期间在拉宾医疗中心住院、实验室确诊为流感的连续成年患者。根据入院时的血细胞计数对患者进行分组：1. 血小板减少症 (<150 K/ml)，2. 淋巴细胞减少症 (<0.5K/ml)，以及 3. 血小板减少症和淋巴细胞减少症。无血小板减少症和淋巴细胞减少症的患者被指定为对照。主要结局是 30 天全因死亡率。使用逻辑回归通过单变量和多变量分析确定风险因素，并报告为比值比 (OR) 和 95% 置信区间 (CI)。结果共纳入625例患者，其中血小板减少症112例（18%），淋巴细胞减少症98例（15.6%），两者均有107例（17%）。30 天粗全因死亡率为 7.6% (48/625)。血小板减少症组的死亡率为 7.1% (8/112)，淋巴细胞减少症组的死亡率为 11.2% (11/98)，两者都有的患者死亡率为 14.9% (16/107)，而对照组的死亡率为 4.2% (13/308) （所有p=0.000）。在多变量回归模型中，显着血小板减少症（<100 K/μL）[OR 5.07，(95% CI 1.5-16.2)[，年龄[OR 1.07，(95% CI 1.02-1.11)]，奥司他韦治疗时间]OR 1.006 , (95%1.002-1.11)] 和显着的呼吸支持 [OR 8.85, (3.4-22.6)] 与 30 天全因死亡率相关。结论 因季节性流感住院且入院时血小板减少<100K/mL 的患者 30 天全因死亡率增加。