Development of an instrument to measure cardiac illness dependency.

Objective: Dependency is frequently mentioned in the literature as a response of patients with cardiac disease. The purpose of this study was to develop and test a measure of dependency occurring in response to a cardiac illness. Illness dependency is defined as the need for emotional protection and social support after a significant change in health.

Design: Instrument development study.

Sample: Convenience sample of 311 patients with cardiac disease.

Results: The final version of the instrument has 25 items, each of which is measured on a 5-point Likert-type scale. Content validity was demonstrated using a panel of experts. Internal consistency of the total scale was 0.90; subscale alpha coefficients ranged from 0.64 to 0.81. Exploratory factor analysis supported a four factor solution: Attention, Reassurance, Concern, and Assistance, which accounted for 57.4% of the variance in scores. Discriminant validity was demonstrated by a low correlation with neuroticism. Social desirability of responses was minimal.

Conclusion: Internal consistency reliability, content validity, and discriminant validity of the Illness Dependency Scale have initial support. This instrument is ready for use in research in which the investigator wishes to measure dependency associated with cardiac illness.