Background: Substituted judgment traditionally has been used often for patient care in Japan regardless of the patient's competency. It has been believed that patient preferences are understood intuitively by family and caregivers. However, there are no data to support this assumption.
Methods: A questionnaire survey was administered to 450 dialysis patients in 15 hospitals to determine their preferences for cardiopulmonary resuscitation (CPR) and dialysis therapy under various circumstances. Simultaneously, we asked family members and physicians of these patients about patient preferences to evaluate their ability to predict what their patients would want. The accuracy of families' and physicians' judgments was assessed by means of kappa coefficient.
Results: Three hundred ninety-eight pairs, consisting of a patient, 1 of his or her family members, and the physician in charge, participated from 15 hospitals in Japan, with a response rate of 88%. Sixty-eight percent of family members correctly predicted patients' current preferences for CPR, 67% predicted patients' preferences for dialysis when they were severely demented, and 69% predicted patients' preferences for dialysis when they had terminal cancer. Corresponding figures for physicians were 60%, 68%, and 66%. When using kappa coefficient analysis, those results indicated that neither family members nor physicians more accurately predicted their patients' wishes about life-sustaining treatments than expected by chance alone. (All kappa coefficients <0.4.)
Conclusion: Our study suggests that patients who want to spend their end-of-life period as they want should leave better advance directives.