Abstract：
BACKGROUND: Legionella pneumonia, a severe form of pneumonia, is caused by Legionella bacteria. The epidemiology of Legionnaires\' disease in Japan, including seasonal trends, risk factors for severe disease, and fatality rates, is unclear. This study examined the epidemiology of Legionella pneumonia in Japan.
METHODS: This retrospective cohort study included data of adult patients hospitalized for Legionella pneumonia (identified using the ICD-10 code, A481) in the Japanese Diagnosis Procedure Combination inpatient database, from April 2011 to March 2021. We performed multivariable logistic regression analysis to explore the prognostic factors of in-hospital mortality.
RESULTS: Of 7370 enrolled hospitalized patients from 1140 hospitals (male, 84.4%; aged >50 years, 87.9%), 469 (6.4%) died during hospitalization. The number of hospitalized patients increased yearly, from 658 in 2016 to 975 in 2020. Multivariable logistic regression analysis revealed that higher in-hospital mortality was associated with older age, male sex, lower body mass index, worsened level of consciousness, comorbidities (congestive heart failure, chronic renal diseases, and metastasis), hospitalization from November to May, and ambulance use. However, lower in-hospital mortality was associated with comorbidity (liver diseases), hospitalization after 2013, and hospitalization in hospitals with higher case volume.
CONCLUSIONS: The characterized epidemiology of Legionella pneumonia in Japan revealed a high mortality rate of 6.4%. To the best of our knowledge, this is the first study to demonstrate a higher mortality rate in winter and in patients with congestive heart failure and metastasis. Further research is needed to understand the complex interplay between the prognostic factors of Legionella pneumonia.
METHODS: This retrospective cohort study included data of adult patients hospitalized for Legionella pneumonia (identified using the ICD-10 code, A481) in the Japanese Diagnosis Procedure Combination inpatient database, from April 2011 to March 2021. We performed multivariable logistic regression analysis to explore the prognostic factors of in-hospital mortality.
RESULTS: Of 7370 enrolled hospitalized patients from 1140 hospitals (male, 84.4%; aged >50 years, 87.9%), 469 (6.4%) died during hospitalization. The number of hospitalized patients increased yearly, from 658 in 2016 to 975 in 2020. Multivariable logistic regression analysis revealed that higher in-hospital mortality was associated with older age, male sex, lower body mass index, worsened level of consciousness, comorbidities (congestive heart failure, chronic renal diseases, and metastasis), hospitalization from November to May, and ambulance use. However, lower in-hospital mortality was associated with comorbidity (liver diseases), hospitalization after 2013, and hospitalization in hospitals with higher case volume.
CONCLUSIONS: The characterized epidemiology of Legionella pneumonia in Japan revealed a high mortality rate of 6.4%. To the best of our knowledge, this is the first study to demonstrate a higher mortality rate in winter and in patients with congestive heart failure and metastasis. Further research is needed to understand the complex interplay between the prognostic factors of Legionella pneumonia.
摘要：
背景：军团菌肺炎，一种严重的肺炎，是由军团菌引起的.日本军团病的流行病学，包括季节性趋势，严重疾病的危险因素，和死亡率，不清楚。这项研究检查了日本军团菌肺炎的流行病学。
方法：这项回顾性队列研究包括因军团菌肺炎住院的成年患者的数据（使用ICD-10代码进行鉴定，A481)在日本诊断程序组合住院数据库中，从2011年4月到2021年3月。我们进行了多变量logistic回归分析，以探讨住院死亡率的预后因素。
结果：来自1140家医院的7370名住院患者（男性，84.4%；年龄>50岁，87.9%），469人(6.4%)在住院期间死亡。住院患者人数逐年增加，从2016年的658到2020年的975。多变量logistic回归分析显示，较高的住院死亡率与年龄，男性,较低的体重指数，意识水平恶化，合并症（充血性心力衰竭，慢性肾脏疾病，和转移），从11月到5月住院，救护车的使用。然而,较低的住院死亡率与合并症（肝病）有关，2013年后住院，并在病例量较高的医院住院。
结论：日本军团菌肺炎的流行病学特征揭示了6.4%的高死亡率。据我们所知,这是第一项研究证明冬季和充血性心力衰竭和转移患者的死亡率更高。需要进一步的研究来了解军团菌肺炎的预后因素之间复杂的相互作用。
方法：这项回顾性队列研究包括因军团菌肺炎住院的成年患者的数据（使用ICD-10代码进行鉴定，A481)在日本诊断程序组合住院数据库中，从2011年4月到2021年3月。我们进行了多变量logistic回归分析，以探讨住院死亡率的预后因素。
结果：来自1140家医院的7370名住院患者（男性，84.4%；年龄>50岁，87.9%），469人(6.4%)在住院期间死亡。住院患者人数逐年增加，从2016年的658到2020年的975。多变量logistic回归分析显示，较高的住院死亡率与年龄，男性,较低的体重指数，意识水平恶化，合并症（充血性心力衰竭，慢性肾脏疾病，和转移），从11月到5月住院，救护车的使用。然而,较低的住院死亡率与合并症（肝病）有关，2013年后住院，并在病例量较高的医院住院。
结论：日本军团菌肺炎的流行病学特征揭示了6.4%的高死亡率。据我们所知,这是第一项研究证明冬季和充血性心力衰竭和转移患者的死亡率更高。需要进一步的研究来了解军团菌肺炎的预后因素之间复杂的相互作用。
