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      Development of a nomogram for predicting in-hospital mortality of patients with exacerbation of chronic obstructive pulmonary disease

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          Background and objectives

          Patients with chronic obstructive pulmonary disease (COPD) often experience exacerbations of their disease, sometimes requiring hospital admission and being associated with increased mortality. Although previous studies have reported mortality from exacerbations of COPD, there is limited information about prediction of individual in-hospital mortality. We therefore aimed to use data from a nationwide inpatient database in Japan to generate a nomogram for predicting in-hospital mortality from patients’ characteristics on admission.


          We retrospectively collected data on patients with COPD who had been admitted for exacerbations and been discharged between July 1, 2010 and March 31, 2013. We performed multivariable logistic regression analysis to examine factors associated with in-hospital mortality and thereafter used these factors to develop a nomogram for predicting in-hospital prognosis.


          The study comprised 3,064 eligible patients. In-hospital death occurred in 209 patients (6.8%). Higher mortality was associated with older age, being male, lower body mass index, disturbance of consciousness, severe dyspnea, history of mechanical ventilation, pneumonia, and having no asthma on admission. We developed a nomogram based on these variables to predict in-hospital mortality. The concordance index of the nomogram was 0.775. Internal validation was performed by a bootstrap method with 50 resamples, and calibration plots were found to be well fitted to predict in-hospital mortality.


          We developed a nomogram for predicting in-hospital mortality of exacerbations of COPD. This nomogram could help clinicians to predict risk of in-hospital mortality in individual patients with COPD exacerbation.

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          Most cited references 27

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          COPD exacerbations: definitions and classifications.

          Chronic obstructive pulmonary disease (COPD) is defined independently of exacerbations, which are largely a feature of moderate-to-severe disease. This article is the result of a workshop that tried to define exacerbations of COPD for use in clinical, pharmacological and epidemiological studies. The conclusions represent the consensus of those present. This review describes definitions, ascertainment, severity assessments, duration and frequency, using varying sources of data including direct patient interview, healthcare databases and symptom diaries kept by patients in studies. The best general definition of a COPD exacerbation is the following: an exacerbation of COPD is a sustained worsening of the patient's condition, from the stable state and beyond normal day-to-day variations that is acute in onset and may warrant additional treatment in a patient with underlying COPD. A more specific definition for studies where a bacteriological cause of exacerbation is being studied is included, as well as simpler definitions for retrospective identification from database sources. Prospective diary card assessments are best recorded as changes from an agreed baseline, rather than absolute symptom severities. Diary cards identify many unreported exacerbations, which on average have similar severities to reported exacerbations. A scale for exacerbation severity is proposed that incorporates in- and outpatient assessments. Exacerbation duration, which also relates to severity, is defined from diary card reports. Healthcare utilisation is not an adequate substitute for severity, depending on many unrelated social and comorbidity factors. It is an outcome in its own right.
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            Defining the Asthma-COPD Overlap Syndrome in a COPD Cohort.

            Asthma-COPD overlap syndrome (ACOS) has been recently described by international guidelines. A stepwise approach to diagnosis using usual features of both diseases is recommended although its clinical application is difficult.
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              Body Mass Index and Mortality in Chronic Obstructive Pulmonary Disease: A Meta-Analysis

              Background The association between body mass index (BMI) and mortality in patients suffering from chronic obstructive pulmonary disease (COPD) has been a subject of interest for decades. However, the evidence is inadequate to draw robust conclusions because some studies were generally small or with a short follow-up. Methods We carried out a search in MEDLINE, Cochrane Central Register of Controlled Trials, and EMBASE database for relevant studies. Relative risks (RRs) with 95% confidence interval (CI) were calculated to assess the association between BMI and mortality in patients with COPD. In addition, a baseline risk-adjusted analysis was performed to investigate the strength of this association. Results 22 studies comprising 21,150 participants were included in this analysis. Compared with patients having a normal BMI, underweight individuals were associated with higher mortality (RR  = 1.34, 95% CI  = 1.01–1.78), whereas overweight (RR  = 0.47, 95% CI  = 0.33–0.68) and obese (RR  = 0.59, 95% CI  = 0.38–0.91) patients were associated with lower mortality. We further performed a baseline risk-adjusted analysis and obtained statistically similar results. Conclusion Our study showed that for patients with COPD being overweight or obese had a protective effect against mortality. However, the relationship between BMI and mortality in different classes of obesity needed further clarification in well-designed clinical studies.

                Author and article information

                Int J Chron Obstruct Pulmon Dis
                Int J Chron Obstruct Pulmon Dis
                International Journal of COPD
                International Journal of Chronic Obstructive Pulmonary Disease
                Dove Medical Press
                29 May 2017
                : 12
                : 1605-1611
                [1 ]Department of Respiratory Medicine, Graduate School of Medicine
                [2 ]Department of Clinical Epidemiology and Health Economics, School of Public Health
                [3 ]Department of Health Services Research, Graduate School of Medicine, University of Tokyo
                [4 ]Department of Health Policy and Informatics, Graduate School of Medicine, Tokyo Medical and Dental University, Bunkyo-ku, Tokyo, Japan
                Author notes
                Correspondence: Yasuhiro Yamauchi, Department of Respiratory Medicine, Graduate School of Medicine, University of Tokyo, 7-3-1, Hongo, Bunkyo-ku, Tokyo 113-8655, Japan, Tel +81 3 3815 5411, Fax +81 3 3815 5954, Email yamauchiy-int@
                © 2017 Sakamoto et al. This work is published and licensed by Dove Medical Press Limited

                The full terms of this license are available at and incorporate the Creative Commons Attribution – Non Commercial (unported, v3.0) License ( By accessing the work you hereby accept the Terms. Non-commercial uses of the work are permitted without any further permission from Dove Medical Press Limited, provided the work is properly attributed.

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