An integral assessment framework of health status in chronic obstructive pulmonary disease (COPD)

Background: To date, many health status instruments exist, but the validity of these instruments is questionable. This is caused by the fact that health status is poorly defined.Purpose: To develop a validated framework that improves conceptual insight into health status and its domains.Methods: Based on theoretical and clinical considerations, we defined the domains of health status into concrete sub-domains by formulating conceptual models. Guided by these conceptual models, for each sub-domain, existing instruments were selected. We validated the conceptual models in the data of 168 COPD patients. Using factor analysis, underlying concepts in the data were identified.Results: The resulting framework included physiological functioning, complaints, functional impairment, and quality of life. These main domains were shown to be subdivided into 15 sub-domains.Conclusions: The present study shows that health status consists of conceptually distinct sub-domains. Integral assessment of health status thus entails measuring all sub-domains. Existing instruments measure only few sub-domains. Integral assessment of health status thus requires the combination of different instruments. The present framework of health status can help in composing such a battery of instruments. Patient profiles obtained by the framework are essential in individualizing treatment. The study was supported by grants from the Dutch Asthma Foundation, GlaxoSmithKline, and the Department of Medical Psychology and Department of Pulmonary Diseases of Radboud University, Nijmegen Medical Center. We are indebted to Dr. F. van den Elshout (pulmonologist, Rijnstate Hospital, Arnhem) and Dr. R. Bunnik (pulmonologist, Maas Hospital, Boxmeer) for their contribution in the patient recruitment, and to the multidisciplinary Taskforce Assessment of the Department of Pulmonary Rehabilitation Unit for their invaluable contributions to the development of the conceptual models.