Measuring quality of life in COPD patients: comparing disease-specific supplements to the EQ-5D-5L

ABSTRACT

Objectives: Patients with chronic obstructive pulmonary disease (COPD) show impairments in health-related quality of life (HRQL). We aimed to find a disease-specific questionnaire for routine application in large cohorts and to assess its additional explanatory power to generic HRQL tool (EQ-5D-5L).

Methods: 1,350 participants of the disease management program COPD received the EQ-5D-5L combined with one of the three disease-specific tools: COPD Assessment Test (CAT), Clinical COPD Questionnaire (CCQ) or St. George’s Respiratory Disease Questionnaire (SGRQ) (450 participants each). We compared metric properties and evaluated the Germany-specific experience-based values (EBVS) and utilities in comparison to the Visual Analogue Scale (VAS). We calculated the additional explanatory power of the identified disease-specific tool on VAS through regression analysis.

Results: 344 patients returned the questionnaire. CAT, CCQ, and SGRQ group did not differ regarding baseline characteristics. The questionnaire specific response rates were 33.7% for CAT, 30.5% for CCQ, and 34.6% SGRQ, thereof 94.0%, 94.3%, and 65.6% valid answers, respectively.

EBVS was better suited to reflect VAS than utilities. CAT increased the explanatory power by 10%.

Conclusion: CAT outperformed CCQ and SGRQ, and it increased the explanatory power of VAS. EBV combined with CAT seems superior to only generic or disease-specific approaches.

KEYWORDS:

• CAT
• CCQ
• COPD
• EQ-5D-5L
• health-related quality of life
• SGRQ

Article Highlights

• COPD is associated with impaired health-related quality of life (HRQL).

• HRQL can be measured by generic (for comparisons among disease groups) and disease-specific tools (for comparison within a disease).

• There are various disease-specific questionnaires for this disease area (COPD Assessment Test (CAT), Clinical COPD Questionnaire (CCQ) or St. George’s Respiratory Disease Questionnaire (SGRQ)). But there is no consensus, which one deals as the best complementary tool to the generic EQ-5D-5L.

• EQ-5D-5L can be valued with two tariffs, the experience-based values and the utilities, and their suitability in comparison to the Visual Analogue Scale is not examined yet.

• We evaluated the three disease-specific tools and two tariffs in a randomly selected cohort of 1,350 patients from a large Statutory Health Insurance Fund (AOK Bavaria) suffering from COPD.

• Based on response rates, ceiling and floor effects and explanatory power, we found CAT as the best supplementary tool and the experience-based values as the better tariff for EQ-5D-5L.

• This box summarizes key points contained in the article.

Declaration of interest

The authors have no relevant affiliations or financial involvement with any organization or entity with a financial interest in or financial conflict with the subject matter or materials discussed in the manuscript. This includes employment, consultancies, honoraria, stock ownership or options, expert testimony, grants or patents received or pending, or royalties.

Reviewer disclosures

Peer reviewers on this manuscript have no relevant financial or other relationships to disclose.

Authors’ contribution

All authors were involved in the conception of the research. RL, AS, and LS initiated the project and decided on research questions and study design. FK prepared the dataset. BS designed analyses, programmed the statistical models and drafted the manuscript in close coordination with FK, RL and LS. All co-authors proofread the manuscript critically and approved its final version.

Ethics approval and consent to participate

The ethic committee of the Ludwig Maximilians University approved the study (Reference number: 17-358). Participants provided written informed consent at the time of inclusion in the disease management program.

Availability of data and materials

The datasets generated and analyzed during the current study are not publicly available due to them containing information that could compromise research participant privacy, but are available from the corresponding author on reasonable request.

Supplementary material

Supplemental data for this article can be accessed here.

Additional information

Funding

The project is funded by the Federal Joint Committee (G-BA), Innovation Fund (funding code 01VSF16025).