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      Seasonality, ambient temperatures and hospitalizations for acute exacerbation of COPD: a population-based study in a metropolitan area

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          Excluding the tropics, exacerbations of chronic obstructive pulmonary disease (COPD) are more frequent in winter. However, studies that directly relate hospitalizations for exacerbation of COPD to ambient temperature are lacking. The aim of this study was to assess the influence of temperature on the number of hospitalizations for COPD.


          This was a population-based study in a metropolitan area. All hospital discharges for acute exacerbation of COPD during 2009 in Barcelona and its metropolitan area were analyzed. The relationship between the number of hospitalizations for COPD and the mean, minimum, and maximum temperatures alongside comorbidity, humidity, influenza rate, and environmental pollution were studied.


          A total of 9,804 hospitalization discharges coded with COPD exacerbation as a primary diagnosis were included; 75.4% of cases were male with a mean age of 74.9±10.5 years and an average length of stay of 6.5±6.1 days. The highest number of admissions (3,644 [37.2%]) occurred during winter, followed by autumn with 2,367 (24.1%), spring with 2,347 (23.9%), and summer with 1,446 (14.7%; P<0.001). The maximum, minimum, and mean temperatures were associated similarly with the number of hospitalizations. On average, we found that for each degree Celsius decrease in mean weekly temperature, hospital admissions increased by 5.04% ( r 2=0.591; P<0.001). After adjustment for humidity, comorbidity, air pollution, and influenza-like illness, only mean temperatures retained statistical significance, with a mean increase of 4.7% in weekly admissions for each degree Celsius of temperature ( r 2=0.599, P<0.001).


          Mean temperatures are closely and independently related to the number of hospitalizations for COPD.

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          The economic impact of exacerbations of chronic obstructive pulmonary disease and exacerbation definition: a review.

          Chronic obstructive pulmonary disease (COPD) poses a significant economic burden on society, and a substantial portion is related to exacerbations of COPD. A literature review of the direct and indirect costs of COPD exacerbations was performed. A systematic search of the MEDLINE database from 1998-2008 was conducted and supplemented with searches of conference abstracts and article bibliographies. Articles that contained cost data related to COPD exacerbations were selected for in-depth review. Eleven studies examining healthcare costs associated with COPD exacerbations were identified. The estimated costs of exacerbations vary widely across studies: $88 to $7,757 per exacerbation (2007 US dollars). The largest component of the total costs of COPD exacerbations was typically hospitalization. Costs were highly correlated with exacerbation severity. Indirect costs have rarely been measured. The wide variability in the cost estimates reflected cross-study differences in geographic locations, treatment patterns, and patient populations. Important methodological differences also existed across studies. Researchers have used different definitions of exacerbation (e.g., symptom- versus event-based definitions), different tools to identify and measure exacerbations, and different classification systems to define exacerbation severity. Unreported exacerbations are common and may influence the long-term costs of exacerbations. Measurement of indirect costs will provide a more comprehensive picture of the burden of exacerbations. Evaluation of pharmacoeconomic analyses would be aided by the use of more consistent and comprehensive approaches to defining and measuring COPD exacerbations.
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            Comorbidities and short-term prognosis in patients hospitalized for acute exacerbation of COPD: the EPOC en Servicios de medicina interna (ESMI) study.

            Comorbidities are frequent in patients hospitalized for COPD exacerbation, but little is known about their relation with short-term mortality and hospital readmissions. Our hypothesis is that the frequency and type of comorbidities impair the prognosis within 12 weeks after discharge. A longitudinal, observational, multicenter study of patients hospitalized for a COPD exacerbation with spirometric confirmation was performed. Comorbidity information was collected using the Charlson index and a questionnaire that included other common conditions not included in this index. Dyspnea, functional status, and previous hospitalization for COPD or other reasons among other variables were investigated. Information on mortality and readmissions for COPD or other causes was collected up to 3 months after discharge. We studied 606 patients, 594 men (89.9%), with a mean (SD) age of 72.6 (9.9) years and a postbronchodilator FEV1 of 43.2% (21.2). The mean Charlson index score was 3.1 (2.0). On admission, 63.4% of patients had arterial hypertension, 35.8% diabetes mellitus, 32.8% chronic heart failure, 20.8% ischemic heart disease, 19.3% anemia, and 34% dyslipemia. Twenty-seven patients (4.5%) died within 3 months. The Charlson index was an independent predictor of mortality (P < .003; OR,1.23; 95% CI, 1.07-1.40), even after adjustment for age, FEV1, and functional status measured with the Katz index. Comorbidity was also related with the need for hospitalization from the ED, length of stay, and hospital readmissions for COPD or other causes. Comorbidities are common in patients hospitalized for a COPD exacerbation, and they are related to short-term prognosis.
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              Associations of ambient air pollution with chronic obstructive pulmonary disease hospitalization and mortality.

              Ambient air pollution has been suggested as a risk factor for chronic obstructive pulmonary disease (COPD). However, there is a lack of longitudinal studies to support this assertion. To investigate the associations of long-term exposure to elevated traffic-related air pollution and woodsmoke pollution with the risk of COPD hospitalization and mortality. This population-based cohort study included a 5-year exposure period and a 4-year follow-up period. All residents aged 45-85 years who resided in Metropolitan Vancouver, Canada, during the exposure period and did not have known COPD at baseline were included in this study (n = 467,994). Residential exposures to traffic-related air pollutants (black carbon, particulate matter <2.5 μm in aerodynamic diameter, nitrogen dioxide, and nitric oxide) and woodsmoke were estimated using land-use regression models and integrating changes in residences during the exposure period. COPD hospitalizations and deaths during the follow-up period were identified from provincial hospitalization and death registration databases. An interquartile range elevation in black carbon concentrations (0.97 × 10(-5)/m, equivalent to 0.78 μg/m(3) elemental carbon) was associated with a 6% (95% confidence interval, 2-10%) increase in COPD hospitalizations and a 7% (0-13%) increase in COPD mortality after adjustment for covariates. Exposure to higher levels of woodsmoke pollution (tertile 3 vs. tertile 1) was associated with a 15% (2-29%) increase in COPD hospitalizations. There were positive exposure-response trends for these observed associations. Ambient air pollution, including traffic-related fine particulate pollution and woodsmoke pollution, is associated with an increased risk of COPD.

                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
                08 May 2015
                : 10
                : 899-908
                [1 ]Acute Geriatric Care Unit, Internal Medicine, University Hospital Mútua de Terrasa, University of Barcelona, Barcelona, Spain
                [2 ]Respiratory Disease Management Plan, Department of Health of the Autonomous Government of Catalonia, Observatory of Respiratory Therapy, Spain
                [3 ]Integrated Care Unit, Medical and Nursing Management, Hospital Clínic Barcelona, Barcelona, Spain
                [4 ]Oficina de Investigación Biosanitaria de Oviedo, Asturias, Spain
                [5 ]Universidad Autonoma de Chile, Santiago, Chile
                [6 ]Health Department, Hospital Clinic, Hospital Clínic & REDISSEC (Health Services Research on Chronic Patients Network), Barcelona, Spain
                [7 ]Chronic Diseases Care Program, Hospital Clinic, Hospital Clínic & REDISSEC (Health Services Research on Chronic Patients Network), Barcelona, Spain
                Author notes
                Correspondence: Pere Almagro, Acute Geriatric Care Unit, Internal Medicine, Hospital Mútua de Terrassa, Pza Dr Robert 5, Terrassa 08221, Barcelona, Spain, Tel +349 3736 5050, Fax +349 3736 5550, Email 19908pam@
                © 2015 Almagro et al. This work is published by Dove Medical Press Limited, and licensed under Creative Commons Attribution – Non Commercial (unported, v3.0) License

                The full terms of the License are available at 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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