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The causes and consequences of seasonal variation in COPD exacerbations.

Donaldson GC, Wedzicha JA - Int J Chron Obstruct Pulmon Dis (2014)

Bottom Line: The seasonality of exacerbations varies with latitude, and is greater in more temperate climates, where there may be less protection from outdoor and indoor cold exposure.Increased susceptibility to viral infection may also be a mechanism mediated through increased airway inflammation or possibly reduced vitamin D levels.The seasonality of exacerbations informs us about the triggers of exacerbations and suggests possible strategies to reduce their number.

View Article: PubMed Central - PubMed

Affiliation: Airways Disease Section, National Heart and Lung Institute, Imperial College London, London, UK.

ABSTRACT
The time of year when patients experience exacerbations of chronic obstructive pulmonary disease is a much-overlooked feature of the disease. The higher incidence of exacerbations in winter has important consequences for patients in terms of increased morbidity and mortality. The seasonality also imposes a considerable burden on already-overloaded health care services, with both primary care consultations and hospital admissions increasing in number. The seasonality of exacerbations varies with latitude, and is greater in more temperate climates, where there may be less protection from outdoor and indoor cold exposure. The precise causes of the seasonality are unknown, but thought to be partly due to the increased prevalence of respiratory viral infections circulating in cold, damp conditions. Increased susceptibility to viral infection may also be a mechanism mediated through increased airway inflammation or possibly reduced vitamin D levels. The seasonality of exacerbations informs us about the triggers of exacerbations and suggests possible strategies to reduce their number.

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Diary-card data collected from the London COPD cohort between November 1995 and November 2012.Notes: Points are the percentage of patient-reporting activity, worsening of respiratory symptoms or onset of exacerbation on days within 1°C, or average peak expiratory flow rate on those days.Abbreviations: COPD, chronic obstructive pulmonary disease; PEFR, peak expiratory flow rate.
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f2-copd-9-1101: Diary-card data collected from the London COPD cohort between November 1995 and November 2012.Notes: Points are the percentage of patient-reporting activity, worsening of respiratory symptoms or onset of exacerbation on days within 1°C, or average peak expiratory flow rate on those days.Abbreviations: COPD, chronic obstructive pulmonary disease; PEFR, peak expiratory flow rate.

Mentions: Single-center studies have made similar observations, albeit in smaller numbers.13 In the UK, between 1995 and 2009, 307 COPD patients enrolled in a London COPD cohort recording worsening of respiratory symptoms with a paper diary to identify exacerbations using a symptomatic definition involving 2 consecutive days of one major respiratory symptom (increased dyspnea, sputum purulence, or sputum volume) plus another respiratory symptom that could be another major symptom or a minor symptom (coryzal, wheeze, sore throat, or cough). The patients experienced 1,052 exacerbations in the cold season (November–February) compared to 676 in the warm season (May–August): an excess of 56.6%.14Figure 2 shows that in this cohort of patients, the percentage of patients reporting respiratory symptoms or the exacerbation of an onset increased as temperatures fall, while outdoor activity and peak expiratory flow rates decrease.


The causes and consequences of seasonal variation in COPD exacerbations.

Donaldson GC, Wedzicha JA - Int J Chron Obstruct Pulmon Dis (2014)

Diary-card data collected from the London COPD cohort between November 1995 and November 2012.Notes: Points are the percentage of patient-reporting activity, worsening of respiratory symptoms or onset of exacerbation on days within 1°C, or average peak expiratory flow rate on those days.Abbreviations: COPD, chronic obstructive pulmonary disease; PEFR, peak expiratory flow rate.
© Copyright Policy
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4199860&req=5

f2-copd-9-1101: Diary-card data collected from the London COPD cohort between November 1995 and November 2012.Notes: Points are the percentage of patient-reporting activity, worsening of respiratory symptoms or onset of exacerbation on days within 1°C, or average peak expiratory flow rate on those days.Abbreviations: COPD, chronic obstructive pulmonary disease; PEFR, peak expiratory flow rate.
Mentions: Single-center studies have made similar observations, albeit in smaller numbers.13 In the UK, between 1995 and 2009, 307 COPD patients enrolled in a London COPD cohort recording worsening of respiratory symptoms with a paper diary to identify exacerbations using a symptomatic definition involving 2 consecutive days of one major respiratory symptom (increased dyspnea, sputum purulence, or sputum volume) plus another respiratory symptom that could be another major symptom or a minor symptom (coryzal, wheeze, sore throat, or cough). The patients experienced 1,052 exacerbations in the cold season (November–February) compared to 676 in the warm season (May–August): an excess of 56.6%.14Figure 2 shows that in this cohort of patients, the percentage of patients reporting respiratory symptoms or the exacerbation of an onset increased as temperatures fall, while outdoor activity and peak expiratory flow rates decrease.

Bottom Line: The seasonality of exacerbations varies with latitude, and is greater in more temperate climates, where there may be less protection from outdoor and indoor cold exposure.Increased susceptibility to viral infection may also be a mechanism mediated through increased airway inflammation or possibly reduced vitamin D levels.The seasonality of exacerbations informs us about the triggers of exacerbations and suggests possible strategies to reduce their number.

View Article: PubMed Central - PubMed

Affiliation: Airways Disease Section, National Heart and Lung Institute, Imperial College London, London, UK.

ABSTRACT
The time of year when patients experience exacerbations of chronic obstructive pulmonary disease is a much-overlooked feature of the disease. The higher incidence of exacerbations in winter has important consequences for patients in terms of increased morbidity and mortality. The seasonality also imposes a considerable burden on already-overloaded health care services, with both primary care consultations and hospital admissions increasing in number. The seasonality of exacerbations varies with latitude, and is greater in more temperate climates, where there may be less protection from outdoor and indoor cold exposure. The precise causes of the seasonality are unknown, but thought to be partly due to the increased prevalence of respiratory viral infections circulating in cold, damp conditions. Increased susceptibility to viral infection may also be a mechanism mediated through increased airway inflammation or possibly reduced vitamin D levels. The seasonality of exacerbations informs us about the triggers of exacerbations and suggests possible strategies to reduce their number.

Show MeSH
Related in: MedlinePlus