Testing a theory of chronic pain.

BACKGROUND: Chronic pain is highly prevalent among older people with arthritis, with depression as its major outcome. The psychopathological process of chronic pain and its outcomes in older people with arthritis have not been the subject of extensive research. The purpose of this study was to test a middle-range theory of chronic pain derived from the Roy Adaptation Model, a nursing theory whose validity has not been tested in the context of chronic pain. METHODS: The study used a convenience sample of 71 older people with arthritis. Two subscales of the Arthritis Impact Measurement Scales were used to measure pain and physical disability. Social support was measured by Part II of the Personal Resource Questionnaire, and the Elderly Daily Stress scale was used to measure daily stress. Participants also completed the 10-item Center for Epidemiological Studies of Depression scale. Univariate analysis, correlation, and path analysis were used to analyse the data. RESULTS: Overall, the data supported the hypothesized model in which pain, disability, social support, age, and gender are predictors of daily stress and daily stress further predicts depression. The direct effects of chronic pain, disability, and social support accounted for 37% of the variance of daily stress, which in turn predicted 35% of the variance of depression. Age and gender had no influence on daily stress. The chi-square index suggested a fit between the data and the model, and therefore the current model is temporarily accepted. Other fit indices also showed a good fit of the model to the data. To simplify the model, a revised version was developed. CONCLUSIONS: This study validated a middle-range theory to explain the effects of chronic pain in older people with arthritis and highlights the importance of chronic pain in the development of depression.