title: Primary care COPD patients compared with large pharmaceutically-sponsored COPD studies: an UNLOCK validation study.
abstract: BACKGROUND
  Guideline recommendations for chronic obstructive pulmonary disease (COPD) are based on the results of large pharmaceutically-sponsored COPD studies (LPCS). There is a paucity of data on disease characteristics at the primary care level, while the majority of COPD patients are treated in primary care.
  
  
  OBJECTIVE
  We aimed to evaluate the external validity of six LPCS (ISOLDE, TRISTAN, TORCH, UPLIFT, ECLIPSE, POET-COPD) on which current guidelines are based, in relation to primary care COPD patients, in order to inform future clinical practice guidelines and trials.
  
  
  METHODS
  Baseline data of seven primary care databases (n=3508) from Europe were compared to baseline data of the LPCS. In addition, we examined the proportion of primary care patients eligible to participate in the LPCS, based on inclusion criteria.
  
  
  RESULTS
  Overall, patients included in the LPCS were younger (mean difference (MD)-2.4; p=0.03), predominantly male (MD 12.4; p=0.1) with worse lung function (FEV1% MD -16.4; p<0.01) and worse quality of life scores (SGRQ MD 15.8; p=0.01). There were large differences in GOLD stage distribution compared to primary care patients. Mean exacerbation rates were higher in LPCS, with an overrepresentation of patients with ≥ 1 and ≥ 2 exacerbations, although results were not statistically significant. Our findings add to the literature, as we revealed hitherto unknown GOLD I exacerbation characteristics, showing 34% of mild patients had ≥ 1 exacerbations per year and 12% had ≥ 2 exacerbations per year. The proportion of primary care patients eligible for inclusion in LPCS ranged from 17% (TRISTAN) to 42% (ECLIPSE, UPLIFT).
  
  
  CONCLUSIONS
  Primary care COPD patients stand out from patients enrolled in LPCS in terms of gender, lung function, quality of life and exacerbations. More research is needed to determine the effect of pharmacological treatment in mild to moderate patients. We encourage future guideline makers to involve primary care populations in their recommendations.
authors.affiliation: Department of Public Health and Primary Care, Leiden University Medical Centre, Leiden, The Netherlands.
authors.forename: Annemarije L
authors.initials: AL
authors.lastname: Kruis
authors.affiliation: Department of Public Health and Caring Science, Family Medicine and Preventive Medicine, Uppsala University, Uppsala, Sweden.
authors.forename: Björn
authors.initials: B
authors.lastname: Ställberg
authors.affiliation: Peninsula Medical School, University of Plymouth, Plymouth, United Kingdom.
authors.forename: Rupert C M
authors.initials: RC
authors.lastname: Jones
authors.affiliation: University of Groningen, University Medical Center Groningen, Department of General Practice, Groningen, The Netherlands; University of Groningen, University Medical Center Groningen, GRIAC Research Institute, Groningen, The Netherlands; Agia Barbara Health Care Centre, Heraklion, Crete, Greece.
authors.forename: Ioanna G
authors.initials: IG
authors.lastname: Tsiligianni
authors.affiliation: Department of Public Health and Caring Science, Family Medicine and Preventive Medicine, Uppsala University, Uppsala, Sweden.
authors.forename: Karin
authors.initials: K
authors.lastname: Lisspers
authors.affiliation: University of Groningen, University Medical Center Groningen, Department of General Practice, Groningen, The Netherlands; University of Groningen, University Medical Center Groningen, GRIAC Research Institute, Groningen, The Netherlands.
authors.forename: Thys
authors.initials: T
authors.lastname: van der Molen
authors.affiliation: University of Groningen, University Medical Center Groningen, Department of General Practice, Groningen, The Netherlands; University of Groningen, University Medical Center Groningen, GRIAC Research Institute, Groningen, The Netherlands.
authors.forename: Jan Willem H
authors.initials: JW
authors.lastname: Kocks
authors.affiliation: Department of Public Health and Primary Care, Leiden University Medical Centre, Leiden, The Netherlands.
authors.forename: Niels H
authors.initials: NH
authors.lastname: Chavannes
mesh_terms: D017677:Age Distribution; D000368:Aged; D002986:Clinical Trials as Topic; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D017410:Practice Guidelines as Topic; D011320:Primary Health Care; D029424:Pulmonary Disease, Chronic Obstructive / Q000628:therapy*; D011788:Quality of Life; D017678:Sex Distribution