Interaction effects in a multivariate model of physician visits by older people.

Previous studies using multivariate models of physician visits by the general population and by older people have failed to take into account the interaction between health, functional impairment, and economic status. Further, they have not inquired fully into effects of psychologic distress and social support on the use of services. Based on the analysis of data from a statewide crosssectional survey of noninstitutionalized older people (N = 2,146), it was discovered that: economic deprivation had a negative main effect and a negative interaction effect (with medical conditions) on the number of self-reported physician visits; both psychosomatic and emotional distress had independent positive effects; the number and self-perceived severity of medical conditions, along with psychosomatic symptoms, were important predictors of the number of visits for older people without ADL impairments, but these factors were nonsignificant among functionally impaired respondents; and social support and emotional distress were the major factors accounting for visits among the severely functionally impaired. The findings point to the importance of integrating concepts from illness-behavior studies into multivariate models of health service use and considering access to medical care within the total context of long-term care services.