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Chronic Obstr Pulm Dis. 2017 Apr 1;4(2):150-158. doi: 10.15326/jcopdf.4.2.2017.0132.

Socioeconomic Status as a Determinant of Health Status Treatment Response in COPD Trials.

Author information

Institute of Infection and Immunity, St George's University of London, United Kingdom.
Evidera, Bethesda, Maryland.
Research and Development, GlaxoSmithKline, Uxbridge, United Kingdom.
Research and Development, AstraZeneca, Gothenburg, Sweden.
Boehringer-Ingelheim Pharmaceuticals, Inc., Ridgefield, Connecticut.
Division of Pulmonary, Critical Care, Sleep and Allergy, Nebraska Medical Center, Omaha.
Research and Development, GlaxoSmithKline, King of Prussia, Pennsylvania.
COPD Foundation, Washington, D.C.


Background: Randomized controlled trials (RCTs) often recruit patients from low and high socioeconomic status (SES) countries, but little is known about the effect of SES on clinical outcomes, particularly patient-centered measures of symptomatic benefit. Methods: Combined individual chronic obstructive pulmonary disease (COPD) patient data from the placebo and long-acting bronchodilator arms of 17 RCTs (from the COPD Biomarkers Qualification Consortium database) were analyzed. Health status was measured using the St George's Respiratory Questionnaire (SGRQ) (minimum clinically important difference [MCID]: 4 units). Trials were grouped into short-term (≤12 months) and medium-term (>12 months to 48 months). A participant's country of residence was categorized into Low/Medium or High SES using World Health Organization criteria. Results: Data from 19765 individuals (6109 Low/Medium SES) were available. Patients in Low/Medium SES countries had more severe disease at baseline. Improvement in SGRQ score with placebo was ≈2 units greater in Low/Medium than in High SES countries; at its greatest, the improvement from baseline exceeded the MCID in Low/Medium countries. This difference was maintained for at least 1 year. Improvement with bronchodilator was also greater in Low/Medium versus High SES countries; overall there was no evidence that the treatment effect versus placebo was different between countries of different SES status. Conclusions: Participants in Low/Medium SES countries experienced significantly larger treatment effects, irrespective of treatment group (placebo and bronchodilator). Despite this, COPD patients in Low/Medium SES countries experienced a health status gain from long-acting bronchodilator treatment that is similar to that seen in High SES countries.


SGRQ; St George’s Respiratory Questionnaire; chronic obstructive pulmonary disease; copd; health status; socioeconomic status

Conflict of interest statement

HM, VSB, MT, RTS, PWJ, NK, SM and SIR are employees of the pharma companies who funded this analysis. SIR is an employee of the University of Nebraska Medical Center. HG and HW participated in this project as employees of Evidera, a company which performs work for hire for multiple pharmaceutical and device companies in outcomes research, and were funded by the CBQC consortium. DM has nothing to declare.

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