Primary care COPD patients compared with large pharmaceutically-sponsored COPD studies: an UNLOCK validation study

PLoS One. 2014 Mar 5;9(3):e90145. doi: 10.1371/journal.pone.0090145. eCollection 2014.


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).

Conclusion: 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.

Publication types

  • Comparative Study
  • Research Support, Non-U.S. Gov't
  • Validation Study

MeSH terms

  • Age Distribution
  • Aged
  • Clinical Trials as Topic
  • Female
  • Humans
  • Male
  • Middle Aged
  • Practice Guidelines as Topic
  • Primary Health Care
  • Pulmonary Disease, Chronic Obstructive / therapy*
  • Quality of Life
  • Sex Distribution

Grants and funding

The International Primary Care Respiratory Group (IPCRG) provided funding for this research project, through an unrestricted grant by Novartis AG, Basel, Switzerland. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.