Health status in COPD cannot be measured by the St George's Respiratory Questionnaire alone: an evaluation of the underlying concepts of this questionnaire.

P N Richard Dekhuijzen,Leonie Daudey,Yvonne F Heijdra,Jan H Vercoulen,Jeannette B Peters,Judith B Prins,Johan Molema

doi:10.1186/1465-9921-11-98

Abstract

BackgroundImproving patients' health status is one of the major goals in COPD treatment. Questionnaires could facilitate the guidance of patient-tailored disease management by exploring which aspects of health status are problematic, and which aspects are not. Health status consists of four main domains (physiological functioning, symptoms, functional impairment, and quality of life), and at least sixteen sub-domains. A prerequisite for patient-tailored treatment is a detailed assessment of all these sub-domains. Most questionnaires developed to measure health status consist of one or a few subscales and measure merely some aspects of health status. The question then rises which aspects of health status are measured by these instruments, and which aspects are not covered. As it is one of the most frequently used questionnaires in COPD, we evaluated which aspects of health status are measured and which aspects are not measured by the St George's Respiratory Questionnaire (SGRQ).MethodsOne hundred and forty-six outpatients with COPD participated. Correlations were calculated between the three sections of the SGRQ and ten sub-domains of the Nijmegen Integral Assessment Framework, covering Symptoms, Functional Impairment, and Quality of Life. As the SGRQ was not expected to measure physiological functioning, we did not include this main domain in the statistical analyses. Pearson's r ≥ 0.70 was used as criterion for conceptual similarity.ResultsThe SGRQ sections Symptoms and Total showed conceptual similarity with the sub-domain Subjective Symptoms (main domain Symptoms). The sections Activity, Impacts and Total were conceptual similar to Subjective Impairment (main domain Functional Impairment). The SGRQ sections were not conceptual similar to other sub-domains of Symptoms, Functional Impairment, nor to any sub-domain of Quality of Life.ConclusionsThe SGRQ could facilitate the guidance of disease management in COPD only partially. The SGRQ is appropriately only for measuring problems in the sub-domains Subjective Symptoms and Subjective Impairment, and not for measuring problems in other sub-domains of health status, such as Quality of Life.

Highlights

Improving patients’ health status is one of the major goals in COPD treatment
Conceptual similarity between sections of the St George’s Respiratory Questionnaire (SGRQ) and sub-domains of the Nijmegen Integral Assessment Framework (NIAF) The SGRQ sections were significantly correlated to many health status aspects, conceptual similarity (r ≥ 0.70) was only reached for two sub-domains of the NIAF (Table 3)
The SGRQ sections Activity, Impacts, and Total were conceptually similar to the NIAF sub-domain Subjective Impairment

Summary

Introduction

Improving patients’ health status is one of the major goals in COPD treatment. Questionnaires could facilitate the guidance of patient-tailored disease management by exploring which aspects of health status are problematic, and which aspects are not. Health status consists of four main domains (physiological functioning, symptoms, functional impairment, and quality of life), and at least sixteen sub-domains. The WHO uses a broader definition of health status, by defining health status as ‘a state of complete physical, mental and social well-being, and not merely the absence of disease or infirmity’. Others [5,6] define health status as an overall concept covering physiological functioning, symptoms, functional impairment, quality of life, and social functioning as important main domains. These main domains were empirically found to be further divided into sixteen sub-domains [7,8], each sub-domain representing a unique aspect of health status. Patient-tailored treatment requires assessment of all these subdomains

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Results

Discussion

Conclusion