Abstract
The aim of this study was to identify factors related to changes in dyspnoea level in the acute and short-term periods after acute exacerbation of chronic obstructive pulmonary disease. This was a prospective cohort study of patients with symptoms of acute chronic obstructive pulmonary disease exacerbation who attended one of 17 hospitals in Spain between June 2008 and September 2010. Clinical data and patient reported measures (dyspnoea level, health-related quality of life, anxiety and depression levels, capacity to perform physical activity) were collected from arrival to the emergency department up to a week after the visit in discharged patients and to discharge in admitted patients (short term). Main outcomes were time course of dyspnoea over the acute (first 24 hours) and short-term periods, mortality and readmission within 2 months of the index episode. Changes in dyspnoea in both periods were related capacity to perform physical activity as well as clinical variables. Short-term changes in dyspnoea were also related to dyspnoea at 24 hours after the ED visit, and anxiety and depression levels. Dyspnoea worsening or failing to improve over the studied periods was associated with poor clinical outcomes. Patient-reported measures are predictive of changes in dyspnoea level.
Introduction
Acute exacerbation of chronic obstructive pulmonary disease (AECOPD) is one of the leading causes of hospitalisation worldwide and also one of the most common causes of emergency department (ED) visits (Citation1). Recent recommendations underline that strategies for prevention of AECOPD are necessary to decrease morbi-mortality and costs associated with this pathology (Citation2).
In Spain, various strategies have been implemented to prevent exacerbations and/or decrease associated hospitalization, for instance, multidisciplinary programs aiming to treat exacerbation in settings other than hospitals (Citation3). Despite this, large numbers of patients with chronic obstructive pulmonary disease (COPD) visit EDs and most of them are hospitalized for their exacerbation. Further, it has been observed that there is great variability in the process of care between regions and centres (Citation4,5).
There are several definitions for AECOPD, and most of them make reference to sustained worsening of dyspnoea as a characteristic feature (Citation6). Dyspnoea is also related to the diagnosis and future risk of exacerbations, as well as limitations in activity and poor health status (Citation6,7). Shortness of breath refractory to usual bronchodilator therapy is often the most distressing symptom during AECOPD and one of the main reasons for hospitalization in these patients (Citation8–10).
It is known that a higher level of dyspnoea in stable periods of disease is related to more frequent exacerbations, higher mortality and deterioration of health-related quality of life (HRQoL) (Citation11,12). Nevertheless, there is a lack of information about the role of dyspnoea in the immediate aftermath of an exacerbation, this being a high risk period for re-exacerbations and death (Citation11,12).
Being dyspnea the key symptom in COPD patients, to identify the factors influencing its changes in an acute phase as is the exacerbation is crucial to determine how to manage them, and what preventive or therapeutic measures can be established. To identify these factors could be very useful if they were modifiable. In this context, identification of these factors could serve physicians to do a more intensive control of patients which present them and to do more emphasis in prevention.
The aim of the present study was to identify factors related to changes in dyspnoea level in the acute period (from arrival at the ED to 24 hours later) and subsequent changes in the short-term (up to 1 week later or discharge in patients who were admitted). We also explored whether the patients with little or no improvement in dyspnoea after the acute period were more likely to have poor outcomes in the short-term or during the at-risk window (2 months).
Material and Methods
Patients with symptoms of COPD exacerbation who attended the EDs of 17 participating hospitals between June 2008 and September 2010 were invited to participate in this prospective cohort study. The Institutional Review Board of each participating hospital approved the study, and before patients were included, they or their caregivers gave informed consent.
Patients were candidates for the study if they presented to the ED of any of the participating hospitals with symptoms consistent with an exacerbation of COPD. Exacerbation was defined as an event in the natural course of the disease characterized by a change in the patient's baseline dyspnoea, cough, and/or sputum that was beyond normal day-to-day variations, was acute in onset, and may have warranted a change in regular medication in a patient with underlying COPD (Citation7). Patients were considered to have been previously diagnosed with COPD if they had obtained a forced expiratory volume in 1 second (FEV1)/forced vital capacity (FVC) ratio < 70%.
Patients not previously diagnosed with COPD but in whom the disease was suspected were also eligible for inclusion in the study. This included smokers or former smokers with a ≥15 pack-year history of smoking and dyspnoea, cough, or expectoration for more than 3 months per year, who were experiencing symptoms compatible with COPD exacerbation. It was also required that the diagnosis be confirmed by spirometry within 60 days after the index episode, at a time when the patient was stable, i.e., in the absence of any worsening of symptoms or changes in background therapy. If a diagnosis of COPD was not confirmed, the patient was excluded from the analysis. All patients were required to have dyspnoea at rest on their arrival to ED.
Patients were excluded from the study if they had COPD complicated by a comorbidity such as pneumonia, pneumothorax, or pulmonary embolism; lung cancer; or left cardiac insufficiency. Other exclusion criteria included a diagnosis of asthma, extensive bronchiectasis, sequelae of tuberculosis, pleural thickening, and restrictive diseases. Patients who did not wish to participate were also excluded.
Variables included in the study
We collected information from the time the patient arrived in the ED up to a week after the visit in discharged patients and to discharge in admitted patients, with follow-up 2 months after the index episode.
Data collected from hospital records and patient medical records included the severity of the exacerbation (gauged by level of consciousness, respiratory rate, heart rate, and blood gas levels, paradoxical breathing and accessory muscle recruitment); baseline COPD severity (based on the FEV1); the presence of comorbidities that affect COPD exacerbation, such as diabetes and cardiac disease; the number of hospital admissions for COPD exacerbation during the previous 12 months; the patient's ability to carry out necessary treatments at home; response to previous treatments; previous use of home oxygen therapy; and demographic variables, such as age and sex (Citation13). In addition, we collected data concerning comorbid conditions included in the Charlson Co-morbidity Index (Citation14), and the presence of dyspnoea at rest (yes or no) on arrival to the ED, based on the assessment of the ED physician at that time. We also studied treatments: inhaled short-or long-acting beta agonist, short- or long acting anticholinergics, oral or inhaled corticosteroid, theophyllines, antibiotics, diuretics, and/or need of noninvasive mechanical ventilation or long-term oxygen therapy.
Patient-reported measures included in the study were level of dyspnoea, capacity for physical activity, and perceived general health status.
Dyspnea at their arrival at ED was measured as presence of dyspnea at rest, yes or not. We asked patients about their dyspnoea level during the day after the arrival to ED using a Likert-scale item created ad-hoc for this study based on modified Borg scale (Citation15). It includes 7 response options that ranged from “very severe difficulty breathing” to “no difficulty at all" (Citation15). We categorized the responses into three categories: “high” if the patients reported a very severe or severe level of difficulty breathing, “moderate,” if the patient reported some or considerable difficulty, and “low” if they said that they had slight or very slight difficulty breathing or no difficulty at all.
Patients were also asked about their level of dyspnoea at baseline using the five-grade modified Medical Research Council (MRC) scale (Citation15) and the scale adapted from Fletcher (Citation16,17): Grade 1, “dyspnoea only with intense and strenuous exercise”; Grade 2, “capable of walking at the same pace as other people my age on the level”; Grade 3, “capable of walking on the level at my own speed without dyspnoea, but not of walking at the same pace as people my age”; Grade 4, “dyspnoea after walking slowly for 100 meters”; and Grade 5, “dyspnoea when resting or after slight effort such as getting dressed.”
With regard to capacity for physical activity, patients were asked to choose one of the following 7 scenarios to describe their condition the day after arrival to the ED: 1) “I am bedridden”; 2) “I can sit up but not get up”; 3) “I am sedentary but get up to go to the bathroom”; 4) “I walk around the room”, 5) “I can do certain physical activities (walking at home)”; 6)“I can walk and climb stairs”; and, 7) “I am not restricted in my activities.” We categorized the patient response for this variable as “low”, for options 1, 2 or 3; “moderate” for 4 or 5, and “high” for 6 or 7. In addition, they were asked to recall their capacity to perform physical activity at baseline and responses categorised as: “low”–“I was bedridden, sedentary or only able to walk more than 100 meters,” “moderate”–“I was able to walk more than 100 meters occasionally,” or “high”–“I was able to do gardening, walk regularly or play sport.” This physical activity scale was based on the health, activity, dyspnea and obstruction (HADO) score (Citation18), already validated, and has been used in previous studies. This scale showed in good correlation with the St. George´s Respiratory Questionnaire activity sub-scale. It also shows in this sample good correlation with the EQ-5D (Pearson ´s r correlation coefficient:0.42 in admitted patients, and 0.49 in those discharged, p for both < 0.0001) and the fatigue scale (r correlation coefficient: 0.39 and 0.30, respectively, p for both < 0.0001).
Patients' perception of their own health status was measured using the first item of the Short Form-36 questionnaire [SF-36], an instrument for measuring generic HRQoL. This item measures current self-perceived health status, and for this study, it was rated on a 6-point scale from “very poor” to “excellent.” We categorized this variable into three categories: “poor” if the patients reported having very poor or poor health status; “moderate” if their response was “fair”; and “good” if it was “good,” “very good” or “excellent” (Citation19).
We also administered the EUROQoL-5D (EQ-5D) questionnaire, a general health assessment instrument. This questionnaire gives an overall score between 0 and 1 for the quality of life of the participant, based on five questions about their state of health in 5 dimensions: mobility, self-care, performance of usual activities, pain or discomfort, and anxiety or depression. Each dimension is rated on a 3-level scale from 1 (no problems/no pain/not worried, sad or unhappy) to 3 (a lot of problems/a lot of pain/very worried, sad or unhappy). The EQ-5D has been shown to be reliable and valid and has been translated into Spanish and validated for the Spanish population (Citation20).
Patients were interviewed twice by trained interviewers using a standardized manual of instructions. Interviewers were directly supervised by the clinical researchers. Admitted patients were interviewed the day after the index ED visit and again just before leaving the hospital. Discharged patients were interviewed by telephone the day after the index ED visit and 7 days later. Clinical records were review up to 2 months after ED visit.
Definition of outcomes
Main outcomes
For analysing changes in dyspnoea during the acute period, we selected patients with dyspnoea at rest on their arrival to the ED, based on the assessment of the ED physician at that time. Dyspnoea was considered to have substantially improved during the acute period in the case of those patients who reported “some,” little,” “very little” or “no” shortness of breath at 24 hours after the ED visit. In those who, after 24 hours after admission reported “a very high level of,” “a high level of” or “considerable” shortness of breath, it was considered that there had been little or no improvement in dyspnoea.
We considered the same categories to characterise changes in dyspnoea during the short-term period, considering changes in dyspnoea from 24 hours after the ED visit to 7 days after the ED visit in discharged patients and to the time of discharge in admitted patients. That is, there was considered to have been little or no improvement in dyspnoea in patients reporting “a very high level of”, “a high level of” or “considerable” shortness of breath a week after the ED visit in those directly discharged from the ED or on the day of discharge they had been admitted to hospital. Otherwise, dyspnoea was considered to have substantially improved.
Other outcomes recorded were intensive care unit (ICU) or intermediate respiratory care unit (IRCU) admission, length of hospital stay in admitted patients, and mortality, during the short-term period (in-hospital mortality or during the seven days after the ED visit in the case of those directly discharged from the ED) and at 2 months after the index episode. We also measured readmission or mortality during the following 2 months after the index episode among those who survived the short-term period.
Statistical analyses
The unit of analysis was the patient. In the case of patients who visited the ED more than once for AECOPD, only the first visit was included in the analysis. Descriptive statistics included frequencies and percentages for categorical variables and means and standard deviation [SD] for continuous variables. These statistics were used to explore the main sociodemographic and clinical characteristics, as well as patient-reported measures at baseline.
On the one hand, to identify factors associated with little or no improvement in dyspnoea in the first 24 hours, only patients with dyspnoea at rest were considered. In that subsample, multilevel multivariable analysis was performed adjusting by hospital. Variables which were significant at the 0.20 level, in the univariate analysis, were considered as potential independent variables for the multilevel multivariable model adjusted by hospital. Factors with a p-value of less than 0.05 in the multivariate analysis were considered to have predictive value. Odds ratios (ORs) and 95% confidence intervals (95% CI) were calculated for the univariate and the multivariate analysis. The predictive accuracy of the model was assessed by area under the curve (AUC) analysis.
On the other hand, to analyse changes in dyspnoea in the short-term period, we first excluded patients who died during admission. Then, a prediction model for little or no improvement in dyspnoea in the short-term period was constructed following the same steps as those outlined for the first model above.
Finally, we assessed the association between little or no improvement in dyspnoea on both time scales (24 hours and short term) and certain key outcomes.
All effects were considered significant at p < 0.05, unless otherwise stated. All statistical analyses were performed using SAS for Windows statistical software, version 9.2 (SAS Institute, Inc., Carey, NC) and R©.
Results
The study included 2487 patients; of these, 1537 were admitted to hospital and 1601 arrived at the ED presenting dyspnoea at rest (). Questionnaires were completed by 2396 patients 24 hours after their arrival at the ED and by 2246 after the short-term period (a response rate of 90%) (Appendix 1).
Figure 1. Flow of patients through the study Q1: First questionnaire, on the day after the ED visit, by trained reviewers in the hospital ward if the patient was admitted and over the telephone in the case of discharged patients. Q2:Second questionnaire, by trained reviewers on the day of discharge from hospital in the case of previously admitted patients and over the telephone in the case of those who had been directly discharged from the ED. Both questionnaires included items related to level of dyspnea, capacity to perform physical activity and health status.
presents baseline characteristics of patients by change in dyspnoea level during the acute and short-term periods. Little or no improvement on these time scales was related to baseline FEV1, breathing and heart rates, dyspnoea level, capacity to perform physical activity and health status. In addition, dyspnoea failing to improve in the short term was related to patient-reported measures at 24 hours and to blood pO2, and in the acute period to blood pH and pCO2.
Table 1. Baseline clinical and demographic characteristics of COPD patients by improvement in dyspnoea.
Predictors and outcomes associated with little or no improvement in the acute period (the first 24 hours)
Baseline severity of COPD (FEV1), pH and heart rate on arrival to the ED, and capacity to perform physical activity at baseline were predictors of little or no improvement in dyspnoea at 24 hours; specifically, this poor course was 1.58 times more likely in those with FEV1 < 50, 1.64 times more likely in those with blood pH between 7.26 and 7.35, and 1.38 times more likely in those with heart rate > 100 beats per minute than in other patients, as well as 2.9 and 1.69 times more likely in those with low and moderate capacity than those with a high capacity to perform physical activity ().
Table 2. Multivariate predictors of little or no improvement in dyspnoea at 24 hours.
We detected statistically significant differences in outcomes between those with little or no improvement in their dyspnoea over the first 24 hours and those reporting a substantial improvement. Those with the poorer course were more frequently admitted to the ICU (0.03) or IRCU (<0.0001), and more likely to die in the short-term period (p = 0.0007) and also in the first (0.0031) or second (p = 0.0074) month after the ED visit, as well as being more frequently readmitted (p = 0.0224) in these 2 months. They also had longer lengths of hospital stay (p < 0.0001) ()
Table 3. Multivariate predictors of little or no improvement in dyspnoea during the short-term period.
Predictors and outcomes associated with little or no improvement in dyspnoea in the short-term
In the case of admitted patients, little or no improvement in dyspnoea was related to the number of previous hospital admissions, dyspnoea level at 24 hours, baseline capacity to perform physical activity and level of anxiety or depression. Specifically, this poor course was more likely in those with three or more admissions in the previous year (OR95CI% = 1.691.14–2.48), greater levels of dyspnoea at 24 hours, lower baseline capacity to perform physical activity and higher levels of anxiety or depression (). In the case of discharged patients, little or no improvement in dyspnoea was more likely in those with dyspnoea at rest on arrival, the highest levels of dyspnoea at baseline and at 24 hours, and higher levels of anxiety or depression ().
Table 4. Association between changes in dyspnoea and outcomes.
Further, patients whose dyspnoea did not substantially improve in the short-term period considered were more likely to be readmitted or die in the 2 months following the index episode. Among patients who were admitted, those who reported little or no improvement in their dyspnoea on this time scale were more likely to die in the month following admission ().
Discussion
Our study has identified factors related to dyspnoea failing to substantially improve and these are also predictive of poor outcomes in the short-term and the so-called “at-risk window” of 2 months after exacerbation. Our data help us to understand changes in dyspnoea level in the acute setting, that is, after stabilization in the ED, and in the short-term (the period between admission and discharge in those who are hospitalized, but also between the ED visit and a week after discharge in those sent home directly from the ED).
Dyspnoea level in stable COPD has been related to mortality, but little is known about the value of this measure in acute exacerbations for predicting mortality in the short-term and the at-risk window. Roche et al. (Citation21) and Tsimogianni et al. (Citation22) found that dyspnoea at baseline measured by the MRC dyspnoea scale was a predictor of in-hospital mortality and of 3-year mortality respectively.
Steer et al., in 2011, explored the predictive value of the extended MRC dyspnoea scale, finding that this version of the scale identified a subgroup of patients at a particularly high risk of in-hospital mortality, with even stronger predictive value than the CURB-65 score in exacerbations complicated by pneumonia (Citation23).
We decided to include patients discharged home from the ED as well as those who were admitted, and this is a strength of our study. In contrast with Steer et al. (Citation23); however, we did not include patients who presented with pneumonia at the time of arrival to the ED (44 patients being excluded for this reason), and hence our results cannot be extrapolated to such cases. We considered pneumonia to be a complication of AECOPD if the consolidation appeared 48 hours after the admission or discharge home from ED, patients with the appearance of consolidation in the first 48 hours being excluded from the study. All the same, only 6 (2.11%) of our patients developed pneumonia.
Changes in dyspnea level at acute period was defined as the evolution of dyspnea at acute setting, from dyspnea at rest at the admission in ED to dyspnea level at the next day. We only be able to explore this changes in those who presented dyspnea at rest at their arrival to ED since emergency physician collected this variable in a dichotomic way (dyspnea at rest yes or not). By this reason we could not generalize our results to those who presented lower levels of dyspnea at their arrival (expected to be milder cases). The second model of this work, which could be performed to explain changes of dyspnea at short term period (from the next day of arrival to ED to a week after the discharge or at discharge time in those hospitalized), took into account all the patients in our sample, those who presented dyspnea at rest and those who did not.
Another limitation of our work is related with its observational nature and the variability of centres and physician who saw these patients. Although we collected and we have adjusted by the treatments prescribed, time from presentation to initiation of appropriate treatment is likely to influence outcome and we did not collect this information. Further studies will be required to show the influence of this variable in the final outcomes.
We have explored changes in dyspnoea level during the first 24 hours day after ED arrival and in the short term thereafter, during hospital admission or the recovery period at home in discharged patients; both were related to poor outcomes, not only mortality but also readmissions and, in the case of changes in the acute period, with poor outcomes during the first day in the ED. These findings may be extremely useful to physicians, to better characterize dyspnoea, and to identify patients whose dyspnoea is most likely to worsen. We have provided explicative models to predict changes in acute and short-term dyspnoea.
Several variables are related to these changes at different times, but certain patient-reported outcomes were repeatedly found to be significant across these models, namely, baseline capacity to perform physical activity, baseline dyspnoea level and level of anxiety or depression. It has previously been suggested that capacity to perform physical activity and anxiety/depression level are associated with the risk of hospitalization for AECOPD (Citation24) and also with the risk of exacerbation (Citation25). We have found that these variables influence dyspnoea levels and, in turn, dyspnoea is related to poor outcomes. Given this, to improve the characterisation and management of dyspnoea, we strongly recommend assessment of these variables in patients with AECOPD.
In spite of no clear evidence that intensive treatment of dyspnoea is able to change outcomes, our results suggest that efforts should be focused on intensive treatment of dyspnoea in the first few hours after the acute phase of exacerbation. Some of these variables are not modifiable at ED and some others are, so, we recommend to explore these variables in the management of COPD, to do all our best to prevent the existence of them, for example, physical activity recommendation and empowerment and education about the disease in order to decrease anxiety and depression level and even to treat them. We think further studies will answer us if interventions in this sense will improve outcomes in COPD.
Conclusions
Our results confirm that a lack of short-term dyspnea improvement predicts poor outcome. Therefore, patients in whom dyspnea does not improve on the short-term should be identified and represent targets for intensified therapy and monitoring. To achieve this would require repeated dyspnea monitoring in the days following treatment initiation.
They also suggest that usual levels of activity, and symptoms of anxiety and depression predict lack of dyspnea improvement and should therefore be identified at entry to trigger intensified therapy and monitoring.
In spite of no clear evidence that intensive treatment of dyspnoea is able to change outcomes, our results suggest that efforts should be focused on intensive treatment of dyspnoea in the first few hours after the acute phase of exacerbation. Further studies are required to test this hypothesis.
Declaration of Interest Statement
No possible conflicts of interest (funding sources for consultancies or studies of products and personal relationships with other people or organizations that could influence (bias) the author's work) exist in this study. The authors alone are responsible for the content and writing of the paper.
ICOP_S_1078784.docx
Download MS Word (65.5 KB)Acknowledgments
We are grateful for the support of the 16 participating hospitals, as well as the ED physicians, other clinicians, and staff members of the various services, research, quality units, and medical records sections of these hospitals. We also gratefully acknowledge the patients who participated in the study. The authors also acknowledge the editorial assistance provided by Julia Fenn.
The IRYSS - COPD group included the following co-investigators: Dr. Jesús Martínez-Tapias (Dirección Económica, Área Gestión Sanitaria Sur Granada); Alba Ruiz (Hospital de Motril, Granada); Dr. Eduardo Briones, Dra. Silvia Vidal (Unidad de Calidad, Hospital Valme, Sevilla); Dr. Emilio Perea-Milla†, Francisco Rivas (Servicio de Epidemiología, Hospital Costa del Sol, Málaga -Red de Investigación en Servicios de Salud en Enfermedades Crónicas (REDISSEC)); Dr. Maximino Redondo (Servicio de Laboratorio, Hospital Costa del Sol, Málaga- Red de Investigación en Servicios de Salud en Enfermedades Crónicas (REDISSEC)); Javier Rodríguez Ruiz (Responsable de Enfermería del Área de Urgencias, Hospital Costa del Sol, Málaga); Dra. Marisa Baré (Epidemiología y Evaluación, Corporació Sanitaria Parc Taulí-CSPT, Sabadell-Red de Investigación en Servicios de Salud en Enfermedades Crónicas (REDISSEC)), Dr. Manel Lujan, Dra. Concepción Montón, Dra. Amalia Moreno, Dra. Josune Ormaza, Dr. Javier Pomares (Servicio de Neumología, CSPT); Dr. Juli Font (Medicina, Servicio de Urgencias; CSPT), Dra. Cristina Estirado, Dr. Joaquín Gea (Servicio de Neumología, Hospital del Mar, Barcelona); Dra. Elena Andradas, Dr. Juan Antonio Blasco, Dra. Nerea Fernández de Larrea (Unidad de Evaluación de Tecnologías Sanitarias, Agencia Laín Entralgo, Madrid-Red de Investigación en Servicios de Salud en Enfermedades Crónicas (REDISSEC)); Dra. Esther Pulido (Servicio de Urgencias, Hospital Galdakao-Usansolo, Bizkaia); Dr. Jose Luis Lobo (Servicio de Neumología, Hospital Txagorritxu, Araba); Dr. Mikel Sánchez (Servicio de Urgencias, Hospital Alto Deba, Gipuzkoa); Dr. Luis Alberto Ruiz (Servicio de Respiratorio, Hospital San Eloy, Bizkaia); Dra. Ane Miren Gastaminza (Hospital San Eloy, Bizkaia); Dr. Ramon Agüero (Servicio de Neumología, Hospital Marques de Valdecilla, Santander); Dr. Gabriel Gutiérrez (Servicio de Urgencias, Hospital Cruces, Bizkaia); Dra. Belén Elizalde (Dirección Territorial de Gipuzkoa); Dr. Felipe Aizpuru (Unidad de Investigación, Hospital Txagorritxu, Álava — Red de Investigación en Servicios de Salud en Enfermedades Crónicas (REDISSEC)); Dra. Inmaculada Arostegui (Departamento de Matemática Aplicada, Estadística e Investigación Operativa, UPV — Red de Investigación en Servicios de Salud en Enfermedades Crónicas (REDISSEC)); Amaia Bilbao (Unidad de Investigación, Hospital Universitario Basurto, Bizkaia — Red de Investigación en Servicios de Salud en Enfermedades Crónicas (REDISSEC)); Dr. Eva Tabernero and Carmen M. Haro (Hospital de Santa Marina); Dr. Cristóbal Esteban (Servicio de Neumología, Hospital Galdakao-Usansolo, Bizkaia); Dra. Nerea González, Susana Garcia, Iratxe Lafuente, Urko Aguirre, Irantzu Barrio, Miren Orive, Edurne Arteta, Dr. Jose M. Quintana (Unidad de Investigación, Hospital Galdakao-Usansolo, Bizkaia — Red de Investigación en Servicios de Salud en Enfermedades Crónicas (REDISSEC)).
Funding
This work was supported in part by grants from the Carlos III Health Institute (PI 06/1010, PI06/1017, PI06/714, PI06/0326, PI06/0664); Department of Health of the Basque Country, Department of Education, Universities and Research of the Basque Government (UE09+/62); the Research Committee of the Hospital Galdakao-Usansolo; the thematic networks-Red IRYSS (Investigacion en Resultados y Servicios Sanitarios)- of the Carlos III Health Institute (G03/220), and the ERDF. No conflicts of interest exist in this study.
Related Research Data
References
- Tsai CL, Sobrino, JA, Camargo, CA, Jr. National study of emergency department visits for acute exacerbation of chronic obstructive pulmonary disease, 1993–2005. Acad Emerg Med 2008; 15(12):1275–1283.
- Andersson F, Borg S, Jansson SA, Jonsson AC, Ericsson A, Prutz C, et al. The costs of exacerbations in chronic obstructive pulmonary disease (COPD). Respir Med 2002; 96(9):700–708.
- Bakerly ND, Davies C, Dyer M, Dhillon P. Cost analysis of an integrated care model in the management of acute exacerbations of chronic obstructive pulmonary disease. Chron Respir Dis 2009; 6(4):201–208.
- Miravitlles M, Murio C, Guerrero T, Gisbert R. Costs of chronic bronchitis and COPD: a 1-year follow-up study. Chest 2003; 123(3):784–791.
- Pozo-Rodriguez F, Lopez-Campos JL, Alvarez-Martinez CJ, Castro-Acosta A, Aguero R, Hueto J, et al. Clinical audit of COPD patients requiring hospital admissions in Spain: AUDIPOC study. PLoS One 2012; 7(7):e42156.
- Parker CM, Voduc N, Aaron SD, Webb KA, O'Donnell DE. Physiological changes during symptom recovery from moderate exacerbations of COPD. Eur Respir J 2005; 26(3):420–428.
- Global Initiative for Chronic Obstructive Lung Disease (2001) Global strategy for the diagnosis, management and prevention of chronic obstructive pulmonary disease (2013). Available from: http://www.goldcopd.org/ ( accessed 6 February, 2014).
- Wang Q, Bourbeau J. Outcomes and health-related quality of life following hospitalization for an acute exacerbation of COPD. Respirology 2005; 10(3):334–340.
- Fan VS, Ramsey SD, Make BJ, Martinez FJ. Physiologic variables and functional status independently predict COPD hospitalizations and emergency department visits in patients with severe COPD. COPD 2007; 4(1):29–39.
- Bahadori K, FitzGerald JM. Risk factors of hospitalization and readmission of patients with COPD exacerbation–systematic review. Int J Chron Obstruct Pulmon Dis 2007; 2(3):241–251.
- Moberg M, Vestbo J, Martinez G, Williams JE, Ladelund S, Lange P, et al. Validation of the i-BODE Index as a predictor of hospitalization and mortality in patients with COPD participating in pulmonary Rehabilitation. COPD 2014; 11(4):381–387.
- Esteban C, Quintana JM, Aburto M, Moraza J, Arostegui I, Espana PP, et al. The health, activity, dyspnea, obstruction, age, and hospitalization: prognostic score for stable COPD patients. Respir Med 2011; 105(11):1662–1670.
- Quintana JM, Esteban C, Barrio I, Garcia-Gutierrez S, Gonzalez N, Arostegui I, et al. The IRYSS-COPD appropriateness study: objectives, methodology, and description of the prospective cohort. BMC Health Serv Res 2011; 11:322.
- Charlson ME, Pompei P, Ales KL, MacKenzie CR. A new method of classifying prognostic comorbidity in longitudinal studies: development and validation. J Chronic Dis 1987; 40(5):373–383.
- Hareendran A, Leidy NK, Monz BU, Winnette R, Becker K, Mahler DA. Proposing a standardized method for evaluating patient report of the intensity of dyspnea during exercise testing in COPD. Int J Chron Obstruct Pulmon Dis. 2012; 7:345–355.
- Mahler DA, Wells CK. Evaluation of clinical methods for rating dyspnea. Chest 1988; 93(3):580–586.
- Fletcher CM, Elmes PC, Fairbairn AS, Wood CH. The significance of respiratory symptoms and the diagnosis of chronic bronchitis in a working population. Br Med J 1959; 2(5147):257–266.
- Esteban C, Quintana JM, Aburto M, Moraza J, Capelastegui A. A simple score for assessing stable chronic obstructive pulmonary disease. QJM Int J Med 2006; 99:751–759.
- DeSalvo KB, Bloser N, Reynolds K, He J, Muntner P. Mortality prediction with a single general self-rated health question. A meta-analysis. J Gen Intern Med 2006; 21(3):267–275.
- Badia X, Schiaffino A, Alonso J, Herdman M. Using the EuroQoI 5-D in the Catalan general population: feasibility and construct validity. Qual Life Res 1998; 7(4):311–322.
- Roche N, Zureik M, Soussan D, Neukirch F, Perrotin D. Predictors of outcomes in COPD exacerbation cases presenting to the emergency department. Eur Respir J 2008; 32(4):953–961.
- Tsimogianni AM, Papiris SA, Stathopoulos GT, Manali ED, Roussos C, Kotanidou A. Predictors of outcome after exacerbation of chronic obstructive pulmonary disease. J Gen Intern Med 2009; 24(9):1043–1048.
- Steer J, Norman EM, Afolabi OA, Gibson GJ, Bourke SC. Dyspnoea severity and pneumonia as predictors of in-hospital mortality and early readmission in acute exacerbations of COPD. Thorax 2012; 67(2):117–121.
- Esteban Cb, Arostegui I, Aburto M, Moraza J, Quintana JM, Aizpiri S et al. Influence of changes in physical activity on frequency of hospitalization in chronic obstructive pulmonary disease. Respirology 2014; 19(3):330–338.
- Laurin C, Moullec Gg, Bacon SL, Lavoie KL. Impact of Anxiety and Depression on Chronic Obstructive Pulmonary Disease Exacerbation Risk. Am J Respir Crit Care Med 2012; 185(9):918–923.
Appendix 1. Characteristics of patients for whom all questionnaires were ompleted and those with incomplete data