title: Characterisation of the frequent exacerbator phenotype in COPD patients in a large UK primary care population.
abstract: BACKGROUND
  The 'frequent exacerbator' is recognised as an important phenotype in COPD. Current understanding about this phenotype comes from prospective longitudinal clinical trials in secondary/tertiary care with little information reported in primary care populations.
  
  
  OBJECTIVE
  To characterize the frequent-exacerbator phenotype and identify associated risk factors in a large UK primary care COPD population.
  
  
  METHODS
  Using a large database of primary care patients from 80 UK general practices, patients were categorised using GOLD 2014 criteria into high and low risk groups based on exacerbation history. A multivariate logistic regression model was used to investigate covariates associated with the frequent-exacerbator phenotype and risk of experiencing a severe exacerbation (leading to hospitalisation).
  
  
  RESULTS
  Of the total study population (n = 9219), 2612 (28%) fulfilled the criteria for high risk frequent-exacerbators. Independent risk factors (adjusted odds ratio [95% CI]) for ≥2 exacerbations were: most severely impaired modified Medical Research Council (mMRC) dyspnoea score (mMRC grade 4: 4.37 [2.64-7.23]), lower FEV1 percent predicted (FEV1 <30%: 2.42 [1.61-3.65]), co-morbid cardiovascular disease (1.42 [1.19-1.68]), depression (1.56 [1.22-1.99]) or osteoporosis (1.54 [1.19-2.01]), and female gender (1.20 [1.01-1.43]). Older patients (≥75 years), those with most severe lung impairment (FEV1 <30%), those with highest mMRC score and those with co-morbid osteoporosis were identified as most at risk of experiencing exacerbations requiring hospitalisation.
  
  
  CONCLUSIONS
  Although COPD exacerbations occur across all grades of disease severity, female patients with high dyspnoea scores, more severely impaired lung function and co-morbidities are at greatest risk. Elderly patients, with severely impaired lung function, high mMRC scores and osteoporosis are associated with experience of severe exacerbations requiring hospitalisation.
authors.affiliation: Centre of Infection and Immunity, The Queen's University of Belfast, UK. Electronic address: l.mcgarvey@qub.ac.uk.
authors.forename: Lorcan
authors.initials: L
authors.lastname: McGarvey
authors.affiliation: Medical Statistics Team, University of Aberdeen, UK.
authors.forename: Amanda J
authors.initials: AJ
authors.lastname: Lee
authors.affiliation: Salford Royal NHS Foundation Trust, Salford, UK.
authors.forename: June
authors.initials: J
authors.lastname: Roberts
authors.affiliation: Box Surgery, Wiltshire, UK.
authors.forename: Kevin
authors.initials: K
authors.lastname: Gruffydd-Jones
authors.affiliation: National Services for Health Improvement, Dartford, UK.
authors.forename: Eddie
authors.initials: E
authors.lastname: McKnight
authors.affiliation: Centre of Academic Primary Care, University of Aberdeen, Aberdeen, UK.
authors.forename: John
authors.initials: J
authors.lastname: Haughney
mesh_terms: D000367:Age Factors; D000368:Aged; D000369:Aged, 80 and over; D002318:Cardiovascular Diseases / Q000453:epidemiology; D003866:Depressive Disorder / Q000453:epidemiology; D004417:Dyspnea / Q000453:epidemiology; D005260:Female; D005541:Forced Expiratory Volume / Q000502:physiology; D006760:Hospitalization / Q000706:statistics & numerical data; D006801:Humans; D016015:Logistic Models; D008297:Male; D008875:Middle Aged; D010024:Osteoporosis / Q000453:epidemiology; D011320:Primary Health Care / Q000706:statistics & numerical data; D029424:Pulmonary Disease, Chronic Obstructive / Q000453:epidemiology / Q000503:physiopathology*; D012307:Risk Factors; D012737:Sex Factors; D006113:United Kingdom / Q000453:epidemiology
keywords: Chronic obstructive pulmonary disease; Frequent exacerbator phenotype; Primary care