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.