Use of a surrogate for the Sickness Impact Profile

The use of a surrogate Sickness Impact Profile (SIP) score was investigated in a sample of 66 chronically or terminally ill homebound patients and their caretakers. Statistically significant differences in category scores (P less than 0.05) were found in only two categories. Profile analysis revealed no systematic differences between patient and caretaker responses, and agreement was generally quite high. Agreement of a surrogate SIP was somewhat lower if the patient was suffering from a terminal condition, if the patient had lower educational attainment, or if the caretaker did not live in the same household as the patient. Agreement did not appear to be affected by a diagnosis of a neurologic or psychiatric condition, by the patient's age or degree of dysfunction, or by the relationship of the caretaker to the patient. Overall, the results of the study are encouraging with regard to use of surrogate SIP total and dimension scores for group-level analysis of chronically ill patients if the surrogate is a family member who is closely involved in the patient's care.