Chest
Volume 130, Issue 4, October 2006, Pages 1117-1128
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Original Research
Does Quality of Life of COPD Patients as Measured by the Generic EuroQol Five-Dimension Questionnaire Differentiate Between COPD Severity Stages?

https://doi.org/10.1378/chest.130.4.1117Get rights and content

Objective

To assess the discriminative properties of the EuroQol five-dimension questionnaire (EQ-5D) with respect to COPD severity according to Global Initiative for Chronic Obstructive Lung Disease (GOLD) criteria in a large multinational study.

Methods

Baseline EQ-5D visual analog scale (VAS) scores, EQ-5D utility scores, and St. George Respiratory Questionnaire scores were obtained from a subset of patients in the Understanding the Potential Long-term Impact on Function with Tiotropium trial, which was a 4-year placebo-controlled trial designed to assess the effect of tiotropium on the rate of decline in FEV1 in COPD patients aged ≥ 40 years, an FEV1 of < 70% predicted, an FEV1/FVC ratio of ≤ 70%, and a smoking history of ≥ 10 pack-years.

Results

A total of 1,235 patients (mean post bronchodilator FEV1, 48.8% predicted) from 13 countries completed the EQ-5D. The EQ-5D VAS and utility scores differed significantly among patients in GOLD stages 2, 3, and 4, also after correction for age, sex, smoking, body mass index (BMI), and comorbidity (p < 0.001). The mean EQ-5D VAS scores for patients in GOLD stages 2, 3, and 4 were 68 (SD, 16), 62 (SD, 17), and 58 (SD, 16), respectively. The mean utility scores were 0.79 (SD, 0.20) for patients in GOLD stage 2, 0.75 (SD, 0.21) for patients in GOLD stage 3, and 0.65 (SD, 0.23) for patients in GOLD stage 4. Effect sizes for the difference in utility scores between patients in GOLD stages 3 and 4 were more than twice as high as those for the difference between patients in GOLD stages 2 and 3. Gender, postbronchodilator FEV1 percent predicted, the number of hospital admissions and emergency department visits in the year prior to baseline measurements, measures of comorbidity, and BMI were independently associated with EQ-5D utility. EQ-5D utility scores also differed between patients from different countries. French patients especially had lower utility scores than US patients. Utility scores calculated with the US value set were on average 5% higher than those calculated with the UK value set.

Conclusions

Increasing severity of COPD was associated with a significant decline in EQ-5D VAS scores and utility scores. These results demonstrate that a generic instrument can assess COPD impact on quality of life and that the scores discriminate between patient groups of known severity. These utility scores will be useful in cost-effectiveness assessments.

Section snippets

Setting and Patients

This study used data from a subset of 1,235 patients from 13 countries who completed the EQ-5D at baseline of the UPLIFT trial.18 Because the EQ-5D was added via protocol amendment more than midway through the recruitment period, only the last 1,235 patients of those countries with significant enrollment remaining could be included in this study. Patients were enrolled sequentially from the time of ethics committee approval of the protocol amendment in each particular country until the

Results

Table 1 shows the characteristics of the 1,235 patients included in the study. The mean duration of COPD was approximately 10 years. Thirty-four percent were active smokers. The mean smoking history was approximately 48 pack-years. Most patients (85.7%) had comorbidity. The median number of concomitant diagnoses per patient was three. Patients most frequently experienced vascular disorders (48%), musculoskeletal disorders (34%), metabolic disorders (32%), GI disorders (26%), and cardiac

Discussion and Conclusion

This study has demonstrated that the GOLD staging of COPD severity corresponds to significant differences in generic health-related quality of life, as assessed by the EQ-5D VAS and utility scores. Importantly, these differences were maintained after correction for other variables that were known to or were expected to affect quality of life, especially comorbidity. This finding demonstrates that GOLD staging of COPD severity corresponds not only to differences in disease-specific quality of

Acknowledgment

We thank our Institute for Medical Technology Assessment colleague Dr. Leida Lamers, who is a member of the EuroQol group, for suggestions on the EQ-5D analyses. We also would like to thank those investigators participating in UPLIFT trial who implemented the administration of the EQ-5D, and all patients who completed the questionnaire. We acknowledge Dominique Julien from Boehringer Ingelheim for providing data management support.

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    This study was financially supported by Boehringer Ingelheim International and Pfizer Global Pharmaceuticals.

    Drs. Rutten-van Mölken and Oostenbrink were reimbursed by Boehringer Ingelheim for consultancy, and for delivering lectures and courses. They have no financial interest in the EQ-5D. Dr. Tashkin is a recipient of research grants from and has been a consultant for Boehringer-Ingelheim Pharmaceuticals Inc.

    Reproduction of this article is prohibited without written permission from the American College of Chest Physicians (www.chestjournal.org/misc/reprints.shtml).

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