Original Contribution
Mortality-related factors after hospitalization for acute exacerbation of chronic obstructive pulmonary disease: the burden of clinical features

https://doi.org/10.1016/j.ajem.2006.09.014Get rights and content

Abstract

Background

There is limited information about factors associated with mortality of patients with chronic obstructive pulmonary disease (COPD) admitted to hospital because of an acute exacerbation.

Methods

A retrospective cohort study including all patients admitted to hospital through our emergency department (ED) was conducted. A total of 972 electronic discharge reports were reviewed. Patient baseline features, aspects concerning acute exacerbation, as well as demographic, cardiac ultrasound, and microbiological data were collected.

Results

In-hospital mortality rate was 6.4%. Of 315 patients with mild exacerbation according to Anthonisen criteria, only 1 died. In the univariate analysis, moderate to severe acute exacerbation of COPD, age older than 75 years, severe COPD, abnormal blood gas values, onset of complications during hospital stay, radiologic consolidation, a positive result in a microbiological respiratory sample, home oxygenotherapy, admission to the intensive care unit, left ventricular ejection fraction, and department of admission were statistically significant (P < .05). The multivariate analysis showed that moderate to severe COPD acute exacerbation (odds ratio [OR] 7.3; 95% confidence interval [CI], 3.6-17.7), age older than 75 years (OR 4.9; 95% CI, 2.3-10.8), severe COPD (OR 4.6; 95% CI, 2.1-10), abnormal blood gas values (OR 4.7; 95% CI, 1.1-19.8), and complication during hospital stay (OR 2.8; 95% CI 1.4-5.4) were independently related to mortality.

Conclusion

We found that clinical aspect appears the most relevant of all potential determinants of in-hospital mortality for patients admitted for acute exacerbation of COPD. Thus, the clinical assessment and therapeutic decision taken in this first moment at the ED are the key that predict the prognosis of this patients. These data suggest that the risk of mortality after the admission to hospital of patients with COPD because of an acute exacerbation can be successfully predicted by making a clinical assessment at the ED.

Introduction

The prevalence of chronic obstructive pulmonary disease (COPD) follows an upward trend and involves high mortality and morbidity [1]. It is one of the few diseases whose incidence continues to rise [2]. Hospitalization for acute exacerbation represents the higher component of socioeconomic burden related to COPD. Yet, little is known about factors associated with mortality [3]. Previous studies have estimated in-hospital mortality for acute exacerbation of COPD to range from 4% to 30% [4], [5], [6], [7]. Several studies have investigated predictive factors related to in-hospital mortality after acute exacerbation of COPD. Some characteristics reported as risk factors are Pao2, oxygen saturation [3], older age [4], [8], cardiac factors [4], [8], [9], other comorbidities [8], low body mass index, severity of illness, serum albumin level, and functional status [9].

The present study was designed to assess mortality rates and potential determinants of in-hospital mortality for patients admitted for acute exacerbation of COPD. To do so, we conducted a retrospective cohort study by obtaining the information from the discharge reports.

Section snippets

Materials and methods

We included all patients with COPD according to Global Initiative for Obstructive Lung Disease (GOLD) criteria [10] admitted to a large university hospital through our emergency department (ED) from January 1, 2004, until December 31, 2004. Each patient was registered in the hospital patient administration system according to International Classification of Diseases, Ninth Revision, Clinical Modification (ICD-9-CM) and was classified considering diagnosis at discharge. Patients with a 491.21

Patient characteristics

The study population was composed of 763 patients that generated 972 admissions (Table 2). Most patients were men (80.7%) and elderly (average age, 75.5 ± 9.34 years). Annual income ranged from $8767 to $25,728. Fifty-five percent were classified as having severe COPD. Only 4.8% had been previously admitted to the ICU. A spirometry was performed in 153 patients during admission, showing a mean forced expiratory volume in 1 second (FEV1) of 46.9%. Two thirds (n = 658) had a moderate to severe

Discussion

This study highlights 3 relevant findings: first, in-hospital mortality of patients for acute exacerbation with COPD is relatively high; second, clinical features are the most reliable factors to predict this outcome; and third, when a patient has acute exacerbation of mild COPD according to classic Anthonisen criteria and is admitted to hospital, mortality tends to zero. These criteria show the most robust association with in-hospital mortality after comparing them with several demographic,

Conclusion

We conclude that the risk of mortality can be predicted through assessment of the clinical situation of the acute exacerbation of patients with COPD at the ED. This is the most powerful variable of the model, complemented by 4 other variables: age older than 75 years, severe chronic COPD, abnormal blood gas values, and onset of complications during admission. These are all aspects easily and usually registered at the ED. Taking into account our main conclusion, the initial management of these

Acknowledgment

The authors are grateful to “Fundación para la investigación Biomédica” del Hospital General Universitario “Gregorio Marañón” for the human support received.

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