Fig 1. Wilson and Cleary’s health-related quality of life conceptual model.

Wilson and Cleary’s model for health-related quality of life [16], revised with permission from JAMA [17]. Wilson and Cleary’s general conceptual model of health links objective biological measurements to the subjective consequences of disease as perceived by patients. In this model, Wilson and Cleary propose causal linkages between 5 health domains: bio-physiological status, symptoms, functional status, general health perception, and quality of life. The arrows represent dominant causal relationships. Reciprocal relationships between the variables are recognised to exist but are not represented, and we did not consider these. The revised version extends the influence of individual and environmental characteristics to all health domains in the model.