Supplementary Material for: A Higher Rate of Pulmonary Fungal Infection in Chronic Obstructive Pulmonary Disease Patients with Influenza in a Large Tertiary Hospital

Background: Influenza is considered a self-limiting disease. However, in patients with chronic obstructive pulmonary disease (COPD), it may result in serious outcomes during the flu season. Objectives: The aims of this retrospective study were to explore the characteristics of hospitalized patients with COPD complicated by influenza and determine the factors affecting the prognosis of these patients. Method: Demographic and clinical data were collected for 278 patients totally from the West China Hospital between January 1, 2016 and February 28, 2018. Results: Among the patients with influenza, the positive fungal culture rate, and the rates of antifungal drug and systemic corticosteroids use were higher for those with COPD than for those without COPD. Respiratory failure was more common in patients with influenza and COPD than in patients with influenza only, while the proportion of severe cases was higher among the former than among the latter. Among the patients with COPD, the positive fungal culture rate, particularly for Aspergillus, and the rate of systemic corticosteroids use were higher for those with influenza than for those without influenza. Multivariate analysis revealed that a COPD history of >20 years and smoking for >20 pack-years were independent factors for susceptibility of COPD patients to influenza. Conclusions: Aspergillus infection seems to be more common in patients with influenza and COPD. In addition, COPD complicated by influenza during the seasonal outbreak can easily progress to a severe disease state. Heavy smokers and patients with a prolonged COPD history are more likely to be infected by influenza.

背景：流行性感冒通常被认为是一种自限性疾病，但对于慢性阻塞性肺疾病（chronic obstructive pulmonary disease, COPD）患者而言，在流感季其可能引发严重不良结局。
目的：本回顾性研究旨在探究合并流行性感冒的COPD住院患者的临床特征，并明确影响此类患者预后的相关因素。
方法：本研究于2016年1月1日至2018年2月28日期间，从华西医院收集了总计278例患者的人口统计学与临床资料。
结果：在流行性感冒患者中，合并COPD者的真菌培养阳性率、抗真菌药物使用率及全身性糖皮质激素使用率均高于未合并COPD者。合并流行性感冒与COPD的患者较仅患流行性感冒的患者更易出现呼吸衰竭，且重症病例占比更高。在COPD患者群体中，合并流行性感冒者的真菌培养阳性率（尤其是曲霉菌阳性率）及全身性糖皮质激素使用率均高于未合并流行性感冒者。多因素分析结果显示，COPD病程＞20年以及吸烟指数＞20包-年是COPD患者易感流行性感冒的独立危险因素。
结论：合并流行性感冒与COPD的患者中，曲霉菌感染更为常见。此外，在季节性流感暴发期间，COPD患者合并流行性感冒后易进展为重症。重度吸烟者及COPD病程较长的患者更易罹患流行性感冒。