Hemoglobin and Clinical Outcomes of in-hospital Patients with Severe Acute Exacerbation of Chronic Obstructive Pulmonary Disease: A multicenter cohort study

Suji Wu¹Qun Yi²Yuanming Luo³Hailong Wei⁴Huiqing Ge⁵Huiguo Liu⁶Xianhua Li⁷Jianchu Zhang⁸Pinhua PAN⁹Mengqiu Yi¹⁰Lina Cheng¹⁰Hui Zhou¹¹Yongjiang Tang^1*Haixia Zhou^1*

• ¹Sichuan University West China Hospital Department of Respiratory and Critical Care Medicine, Chengdu, China
• ²Sichuan Cancer Hospital and Institute, Chengdu, China
• ³State Key Laboratory of Respiratory Disease, Medical University, Guangzhou, China
• ⁴Department of Respiratory and Critical Care Medicine, People’s Hospital of Leshan, Leshan, China
• ⁵Zhejiang University School of Medicine Sir Run Run Shaw Hospital Department of Respiratory and Critical Care Medicine, Hangzhou, China
• ⁶Huazhong University of Science and Technology Tongji Medical College Tongji Hospital, Wuhan, China
• ⁷The First People's Hospital of Neijiang, Neijiang, China
• ⁸Department of Respiratory and Critical Care Medicine, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology,, Wuhan, China
• ⁹Department of Respiratory and Critical Care Medicine, Xiangya Hospital, Central South University, Changsha, China
• ¹⁰Department of Emergency, the First People’s Hospital of Jiujiang, Jiujiang, China
• ¹¹Affiliated Hospital of Chengdu University, Chengdu, China

Background Hemoglobin is one of the most common laboratory tests for hospitalized patients, and both anemia and polycythemia are common comorbidities in severe acute exacerbation of chronic obstructive pulmonary disease (AECOPD). However, limited evidence focuses on the predictive value of anemia or polycythemia for in-hospital adverse outcomes of severe AECOPD. Methods The patients hospitalized for severe AECOPD were prospectively enrolled from ten medical centers in China. They were categorized into three groups: anemia, normal, and polycythemia, based on their hemoglobin levels on-admission. The adverse outcomes which included all-cause in-hospital mortality, invasive ventilation, and intensive care unit ( ICU) admission. 2 / 16 Results A total of 9660 AECOPD inpatients were included. The cohort identified a significant association between anemia and adverse outcomes when compared to the normal group (5.20% vs 2.80%, P < 0.001), including In-hospital mortality (1.12% vs 0.29%, P < 0.001), invasive ventilation (2.12% vs 1.19%, P=0.001), ICU admission (4.24% vs 2.41%, P < 0.001). When hemoglobin was further categorized from <6 /dl to ≥20 g/dl, and 12 to <16 g/dl was taken as reference, ORs for adverse outcomes increased with decreased hemoglobin in the overall cohort, hemoglobin<60g/dl (OR=7.714, 95% CI: 2.622~20.887), hemoglobin 6 to <9 g/dl (OR=3.284, 95% CI: 2.142~4.93). Conversely, no significant relationship was observed between polycythemia and adverse outcomes when compared to the normal group. Additionally, compared with normal group,participants with anemia were found to be older and showed elevated levels of WBC, Neutrophil ratio, PCT, CRP, serum G test positive rate ,GM test positive rate, BUN, creatinine and D-dimer. Conclusion While there is no effect of polycythemia on adverse outcomes in severe AECOPD inpatients, anemia on-admission, particularly <9 g/dl, is associated with a heightened risk of adverse outcomes, which may serve as an effective biomarker of poor prognosis among inpatients with severe AECOPD.