Cynical hostility, powerful others control expectancies, and patient adherence in hemodialysis

Objective: The present study examined the joint role of cynical hostility and powerful others health locus of control expectancies in predicting regimen adherence in a sample of center hemodialysis patients. Method: Forty-eight hemodialysis patients completed the Cook-Medley Hostility (He) Scale and the Powerful Others Health Locus of Control (PHLC) scale. Adherence to the fluid-restriction and phosphorus reduction components of the treatment regimen was assessed by examining patients' interdialysis session weight gains and serum phosphorus (P) levels. Results: In a hierarchical regression analysis, higher hostility was associated with significantly higher serum P levels indicating poorer dietary and medication adherence. The main effect for hostility was qualified by the interaction of hostility and PHLC. This pattern indicated that the deleterious effect of hostility on adherence was most pronounced among patients possessing the expectancy that positive health outcomes are not strongly contingent on the actions or advice of powerful others (eg; health care providers). Similar analyses failed to show significant effects for hostility or PHLC in the prediction of interdialytic weight gain. Conclusions: The present findings suggest that jointly assessing hostility and health-related expectancies may be useful in identifying chronically ill patients who are potentially at risk for difficulties in performing a prescribed regimen.