UC San Diego

Systemic Sclerosis (SSc) is a rheumatic disease characterized by fibrosis of the skin and internal organs. Patients are at risk for poor quality of life, including significant pain. This dissertation evaluated a biopsychosocial model of pain-related quality of life in SSc. Data from the Genetics versus ENvironment In Scleroderma Outcome Study (GENISOS), a prospective cohort study of patients with SSc were used to test the study aims. Study 1 used baseline data to evaluate the factor structure of the Illness Behavior Questionnaire. Four previously derived solutions were tested but none were sufficiently valid or reliable. Exploratory analysis suggested that there were five factors that were relevant to SSc patients : Symptom Bother, Health Worry, Interpersonal Functioning, Other Life Worries, and Affective Inhibition. These indices were related to fatigue, pain, disability, social support, and mental health but not disease severity. Study 2 utilized baseline data to derive biopsychosocial profiles of SSc patients based on indicators of disease severity, perceived physical health, health worry, mental health, and social support. Three classes, which were distinguished by different trait patterns, were termed Managing, Resilient, and Distressed. Results suggested that the Distressed group, which represented individuals with less severe disease but poor psychosocial functioning had the highest pain and analgesic usage. Study 3 evaluated pain over time with regard to medical, psychological, and social characteristics. Pain generally improved for all patients. Individuals with diffuse disease reported worse initial pain, although both classifications had same rate of change. However, when psychosocial characteristics were added to the model, disease classification was no longer a significant predictor. Individuals with better mental health and perceived physical health reported better pain at disease onset. Change in pain over time was moderated by perceived physical health and social support. Overall, the findings suggest that, even in the context of a disease which is characterized by significant damage of bodily tissue, the overall experience of pain was best explained by psychological and social phenomena. Emotional and social functioning, which are potentially modifiable risk factors, may be important targets for comprehensive pain management in this population