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* From the Department of Anaesthesia (Drs. Steinmetz and Rasmussen), Centre of Head and Orthopaedics, Copenhagen University Hospital; and Mobile Emergency Care Unit (Dr. Nielsen), Copenhagen Hospital Corporation, Copenhagen, Denmark.
Correspondence to: Jacob Steinmetz, MD, Department of Anaesthesia, Centre of Head and Orthopaedics, 4231, Copenhagen University Hospital, Rigshospitalet, DK-2100 Copenhagen, Denmark; e-mail: jacobsteinmetz{at}dadlnet.dk
Abstract
Study objectives: Our aim was to assess long-term prognosis for patients with an exacerbation of COPD who were treated by the anesthesiologists of the Mobile Emergency Care Unit (MECU) of Copenhagen. We specifically sought to examine whether mortality was different among patients released before hospital admission and those admitted to the hospital.
Design: An observational cohort study with 5-year follow-up.
Setting: Prehospital and university hospital.
Patients: Patients with exacerbation of COPD treated by the MECU.
Measurements: We included all patients treated from 2000 to 2001. In September 2005, we conducted a search to find out whether these patients were still alive, and we analyzed survival using Kaplan-Meier statistics and log-rank test. Patients admitted to the hospital (primarily or secondarily) were compared to patients treated and released before hospital admission.
Results: In total, 573 patients with COPD had 995 episodes of exacerbation treated by the MECU in the 2-year period. On September 1, 2005, only 155 patients (27%) were alive. In 245 of the exacerbation episodes (25%) among 163 patients, hospital admission was not necessary primarily, but in 42 of these exacerbations (17%), secondary admission occurred within 48 h. Mortality was significantly higher (p = 0.02) in patients admitted to the hospital either primarily or secondarily, compared to patients treated and released before admission to the hospital.
Conclusions: Mortality was high among COPD patients. Less than one fifth of patients treated at home and released are admitted to hospital secondarily. Mortality was significantly higher among admitted patients. A set of criteria selecting the patient prone to secondary admission is desirable.
Key Words: COPD • dyspnea • emergency medical services • mortality • prehospital emergency care • prognosis
Acute exacerbation among patients with COPD is a common and a very serious condition. It is characterized by dyspnea, usually as a result of bronchospasm, resulting in hypoxemia and hypercapnia. Other mechanisms such as air trapping and hyperinflation can contribute to the dyspnea that accompanies an acute exacerbation. Pulmonary infection is a common cause of COPD exacerbations.1 In Denmark, an estimated 200,000 of 5 million people (4%) have COPD, resulting in 3,800 residents deaths (0.07%) annually.2 On a global basis, COPD is a cause of death that continues to have a rising mortality rate, which makes COPD a substantial burden on the health-care system that will continue to rise in the next decade, making it the fifth-leading cause of disability and mortality in the world in 2020.3 Often, the exacerbation leads to admission of the patient to the hospital; in general, the hospital stay is long lasting, and in-hospital mortality is 8 to 24.5%.4567 An American multicenter study8 found a median cost of $7,100 for each hospital stay and 1-year mortality of 43%. A Danish study9 found nearly the same 1-year mortality: 36% after hospital discharge. In addition, patients are frequently readmitted to the hospital. In one study8 50% of all patients were readmitted within 6 months.
Consequently, COPD is a common disease with a considerable use of health-care resources. Prehospital treatment and release of COPD patients reduces the number of hospital admissions, which results in a saving for the health-care system.10 This makes prehospital treatment of COPD a rational way of overcoming the present and future burdens on the health-care system, on the premise that it is safe for the patients. The aim of this study was to assess long-term prognosis for patients with COPD who were treated by the anesthesiologists of the Mobile Emergency Care Unit (MECU) of Copenhagen. We specifically sought to examine whether mortality was different between patients released before hospital admission and those admitted to hospital.
Materials and Methods
We analyzed all episodes of exacerbation among patients with COPD treated by the MECU from 2000 to 2001 due to an emergency 112 telephone call. In September 2005, we conducted a search to find out which patients were still alive. Groups were classified into patients admitted to the hospital (primarily or secondarily) or treated and released before hospital admission.
Study Area and Population
Copenhagen is the capital of Denmark. The city covers 97 square kilometers, with a resident population of 590.000 increased by approximately 10% in the daytime.
Emergency Medical Services
Consistent with the European Union recommendations, we have a single emergency telephone number, 112, which puts the caller in direct contact with the emergency dispatch center. In Copenhagen, emergency medical services (EMS) are two tiered. The basic life support (BLS) unit, equipped with two BLS providers and, among other things, oxygen and bronchodilators for inhalation, is called out from eight different locations, 24 h a day and 7 days a week. The MECU is an advanced life support (ALS) unit based at the main fire station, located in the geographic center of Copenhagen. The MECU is staffed with a specialist in anesthesiology and intensive care and a specially trained ALS provider. The MECU carries various equipment and all drugs and treatment modalities for ALS. In case of presumed severe dyspnea, the BLS unit and the MECU are dispatched simultaneously, and they rendezvous at the incident location. Treatment is provided according to guidelines. The basic treatment for severe dyspnea is inhalation of a ß2-agonist (terbutaline), 5 to 10 mg, via an oxygen-driven jet nebulizer. Ipratropium, 0.5 mg, is added if necessary to the inhaled solution. If the dyspnea persists, judged by the physician, the patient is administered 30 to 60 mg of methylprednisolone IV and then transported to the hospital. During the period of investigation, ß2-agonist (terbutaline), 0.5 mg IV, was used occasionally, and theophyllamine, 220 mg IV, was used in selected situations.
The patient is given permission to remain at home if a substantial and lasting improvement is obtained and mental status, hemodynamics, and pulse oximetry results are acceptable after removal of supplemental oxygen. Furthermore, it is mandatory that congestive heart failure is not suspected and the patient is attended by a competent adult. Otherwise, the patient is admitted to hospital. It is essential that the patient and his/her relatives feel comfortable with the decision to remain at home, and they are encouraged to make an emergency call in case of a relapse. Arterial blood gas analysis or peak expiratory flow are not used in this prehospital setting.
No specific follow-up measures were recommended following primary discharge to home, except the above-mentioned advice to make an emergency telephone call. The mean response time is 5 min, making the MECU readily available at all times.11 After hospitalization, a supported discharge has been partially implemented in Copenhagen since June 2004 resembling the method described by Sala et al.12
Data Collection
The doctor of the MECU decides, on location, whether the dyspnea episode is to be identified as an exacerbation of COPD or another diagnosis. The MECU physician completes a patient encounter form in connection with each dispatch. Information from this medical record is incorporated into a database (Access; Microsoft Corporation; Redmond, WA). All diagnoses and demographic data are registered. The database is then cross-referenced with two Danish national registries: the National Patient Register and the Central Personal Registry. We used the unique personal identification number that all Danish citizens are assigned to locate these patients. We searched the National Patient Register to check for recurrent contacts to the health-care system, resulting in admission to the hospital within 48 h after first contact, and we used the Central Personal Registry to assess whether patients were alive on September 1, 2005. The same patient could be enrolled several times, but in the survival analysis each patient appeared only once.
Statistical Analysis
Continuous data are reported as median with (5 to 95% percentile) proportions with 95% confidence intervals. Survival was analyzed using Kaplan-Meier statistics and log-rank test. We counted the time from the emergency call to death of any cause, and we stratified survival according to hospitalization on one or several occasions. We considered p values 
0.05 to be statistically significant. Data analysis and statistical evaluation were performed using a commercial statistical package (version 9.1; SAS Institute; Cary, NC).
Ethics
Since all data were immediately accessible in existing databases, informed consent from patients and approval from the local Ethics Committee were, according to Danish law, not required.
Results
During the period of inclusion (January 1, 2000, to December 31, 2001) a total of 472,202 emergency calls were recorded, leading to dispatch of the MECU in 16,036 cases, resulting in 12,979 patient contacts (Fig 1 ). In total, 995 episodes of COPD exacerbation were identified in 573 patients treated by the MECU in the 2-year period; 338 patients (59%) were women, and the overall median age was 73 years (range, 57 to 87 years). In 245 of the exacerbation episodes (25%) among 163 patients, hospital admission was not necessary primarily; 42 secondary admissions (17%) occurred within 48 h. One-year all-cause mortality for all 573 COPD patients was 38%, and on September 1, 2005, only 155 patients (27%) were alive (Fig 2 ). In total, 122 patients remained at home > 48 h, with a significantly (p = 0.02) lower mortality compared to the 451 hospitalized patients (Fig 3 ). Although mortality was higher among the hospitalized patients, there was no significant difference in mortality between primarily and secondarily admitted patients (Fig 4 ). Three patients who remained at home died within 48 h after the MECU contact. One patient had terminal pulmonary cancer. Another patient with terminal COPD was treated with domiciliary oxygen therapy, lived in a nursing home, and was comatose. The third patient was a 69-year-old woman receiving domiciliary oxygen as well. She was hypoxemic (oxygen saturation, 77%) but responded well to the treatment, and saturation increased to 94%. Although she still had bronchospasm, she remained at home against the advice of the MECU physician who recommended hospitalization. She was alert (Glasgow coma score of 15) at that time, and it was decided to accept her decision.
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Patients with COPD have a poor long-term prognosis. We found a high mortality: more than every third patient died within a year after a MECU contact. This is consistent with other studies489 in which 1-year mortality rates range from 23 to 43%. This adds to the fact that COPD is a very serious condition and therefore an economic burden on the health-care system. With the increasing incidence of COPD, there is a growing demand for an optimal treatment in the population. Prehospital treatment by EMS is an alternative to admission to the hospital and is probably cost-efficient, as fewer hospitalizations are needed, and we have shown that 25% remained at home after prehospital treatment and only 17% of these were admitted secondarily. Altogether, patients in 20% of all episodes of exacerbations can thereby avoid hospitalization, relieving the health-care system of some load.
We found that mortality was less in those who stayed at home. The explanation is probably that the MECU physician is capable of identifying the patients with the best prognosis to be released at home after treatment. The secondarily admitted patients are not worse off even if they are admitted later, since they have the same mortality as those with primary admissions. This suggests that prehospital treatment and release of COPD patients by a MECU physician is safe.
Of nearly 1,000 contacts, the group of interest is 41 secondarily admitted patients. Although they are only a few patients (4%), they are important to identify at an earlier stage. We need a set of criteria to predict the patients who are secondarily hospitalized in order to admit them beforehand, at the first MECU contact. We do not know if the patients showed any signs of severe morbidity at the first contact and thereby unrightfully were left at home, or if the progression of the exacerbation just worsened. Further investigation is needed to elucidate this question. Perhaps objective assessments such as peak expiratory flow or arterial blood gas analysis could reveal a specific cutoff value, to determine whether the patient should be hospitalized or not. A limitation of the study is that we have not recorded details concerning the lung function. It is possible that patients who were able to remain at home had less severe disease, thereby accounting for their lower mortality. However, we consider prehospital treatment as only an alternative to hospitalization, not as the preferred choice. No rigorously defined criteria of persisting dyspnea were used. Therefore, the decision of hospitalization may vary between different clinicians. Even though this category of patients has a high mortality, we found that it was safe to treat and release patients at home and thereby relieve the health-care system of a substantial economic burden that is rising.
Conclusion
Mortality is high among COPD patients. Less than one fifth of primarily treated and released patients are admitted to hospital secondarily. Mortality was significantly higher among admitted patients. A set of criteria selecting the patient prone to secondary admission is desirable.
Acknowledgements
We thank to Bettine Skaaning, secretary at the MECU, for her work on the database.
Footnotes
Abbreviations: ALS = advanced life support; BLS = basic life support; EMS = emergency medical services; MECU = Mobile Emergency Care Unit
There is no financial support or author involvement in organizations with financial interest in the subject of this article.
Received for publication December 20, 2005. Accepted for publication February 20, 2006.
References
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