Testing a theory for health-related quality of life in cancer patients: A structural equation approach

The purpose of this study was to test a Roy Adaptation Model-based theory o f health-related quality of life in patients with newly diagnosed cancer. U sing a structural equation model, health-related quality of life (HRQOL) wa s regarded as a latent variable measured by 4 empirical indicators represen ting the 4 biopsychosocial response modes of the Roy Adaptation Model (RAM) . The response modes are physiologic, self-concept, interdependence, and ro le function. These were empirically represented by physical symptoms, affec tive status, social support, and functional support, respectively. In this secondary analysis, 3 RAM propositions were tested in a sample of 375 newly diagnosed postsurgical cancer patients 60 years and over. These were: (a) that the 4 response modes are interrelated; (b) that environmental stimuli of gender, race, age, income, marital status, cancer treatment, and severit y of illness influence the biopsychosocial response modes; and (c) that the biopsychosocial responses soon after diagnosis predict biopsychosocial res ponses 3 months later. The analyses did not support the proposition that al l 4 response modes were interrelated. The results, however, revealed that s everity of illness and adjuvant cancer treatment had the strongest associat ion with the biopsychosocial responses and should be considered the focal e nvironmental stimuli. The remaining environmental stimuli can be considered contextual. Also, the proposition that initial biopsychosocial responses p redicted later responses was supported. (C) 1999 John Wiley & Sons, Inc.