Purpose We aim to assess if air pollution levels and climatological factors are associated with hospital admissions for exacerbation of chronic obstructive pulmonary disease (COPD) in Spain from 2004 to 2013. Methods We conducted a retrospective study. Information on pollution level and climatological factors were obtained from the Spanish Meteorological Agency and hospitalizations from the Spanish hospital discharge database. A case-crossover design was used to identify factors associated with hospitalizations and in hospital mortality. Postal codes were used to assign climatic and pollutant factors to each patient. Results We detected 162,338 hospital admissions for COPD exacerbation. When seasonal effects were evaluated we observed that hospital admissions and mortality were more frequent in autumn and winter. In addition, we found significant associations of temperature, humidity, ozone (O 3 ), carbon monoxide (CO), particulate matter up to 10 μm in size (PM 10 ) and nitrogen dioxide (NO 2 ) with hospital admissions. Lower temperatures at admission with COPD exacerbation versus 1, 1.5, 2 and 3 weeks prior to hospital admission for COPD exacerbation, were associated with a higher probability of dying in the hospital. Other environmental factors that were related to in-hospital mortality were NO 2 , O 3 , PM 10 and CO. Conclusions Epidemiology of hospital admissions by COPD exacerbation was negatively affected by colder climatological factors (seasonality and absolute temperature) and short-term exposure to major air pollution (NO 2 , O 3 , CO and PM 10 ).

Background: In chronic obstructive pulmonary disease (COPD), the “obesity paradox” is a phenomenon without a clear cause. The objective is to analyze the complications of COPD patients according to their body mass index (BMI). Methods: An observational study with a six-year prospective follow-up of 273 COPD patients who attended a spirometry test in 2011. Survival and acute events were analyzed according to the BMI quartiles. Results: A total of 273 patients were included. BMI quartiles were ≤24.23; 24.24–27.69; 27.70–31.25; ≥31.26. During the follow-up, 93 patients died. No differences were found in exacerbations, pneumonia, emergency visits, hospital admissions or income in a critical unit. Survival was lower in the quartile 1 of BMI with respect to each of the 2–4 quartiles (p-value 0.019, 0.013, and 0.004, respectively). Advanced age (hazard ratio, HR 1.06; 95% confidence interval, CI 1.03–1.09), low pulmonary function (HR 0.93; 95% CI 0.86–0.99), exacerbator with chronic bronchitis phenotype (HR 1.76; 95% CI 1.01–3.06), high Charlson (HR 1.32, 95% CI 1.18–1.49), and the quartile 1 of BMI (HR 1.99, 95% CI 1.08–3.69) were identified as risk factors independently associated with mortality. Conclusions: In COPD, low BMI conditions a lower survival, although not for having more acute events.

Background Chronic obstructive pulmonary disease (COPD) usually occurs alongside other conditions. Few studies on comorbidities have taken into account the phenotypes of COPD patients. The objective of this study is to evaluate the prevalence of comorbidities included in the Charlson index and their influence on the survival of patients with COPD, taking phenotypes into account. Methods An observational study was conducted on a group of 273 patients who had COPD and underwent spirometry in the first half of 2011, with a median prospective follow-up period of 68.15 months. The survival of these patients was analyzed according to the presence of various comorbidities. Results Of the 273 patients, 93 (34.1%) died within the follow-up period. An increased presence of chronic ischemic heart disease (CIHD), chronic heart failure (CHF), chronic kidney disease (CKD), and malignancy was found in deceased patients. All of these conditions shorten the survival of COPD patients globally; however, when considering phenotypes, only CHF influences the exacerbator with chronic bronchitis phenotype, CKD influences the non-exacerbator phenotype, and malignancy influences the positive bronchodilator test (BDT) and exacerbator with chronic bronchitis phenotypes. In the multivariate model, advanced age (hazard ratio, HR: 1.05; p =0.001), CHF (HR: 1.74; p =0.030), and the presence of malignancy (HR: 1.78; p =0.010) were observed as independent mortality risk factors. Conclusion The survival is shorter in the presence of CIHD in overall COPD patients and also CHF, CKD, and malignancy for certain phenotypes. It is important to pay attention to these comorbidities in the comprehensive care of COPD patients.

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