Does nonresponse bias the results of retrospective surveys of end-of-life care?

Abstract

Objectives: To evaluate the effect of nonresponse bias on reports of the quality of end-of-life care that older adults receive.

Design: Nationwide retrospective survey of end-of-life care.

Setting: Sixty-two Veterans Affairs Medical Centers.

Participants: Patients were eligible if they died in a participating facility. One family member per patient was selected from medical records and invited to participate.

Measurements: The telephone survey included 14 items describing important aspects of the patient's care in the last month of life. Scores (0-100) reflect the percentage of items for which the family member reported that the patient received the best possible care, and a global item defined the proportion of families who said the patient received "excellent" care. To examine the effect of nonresponse bias, a model was created to predict the likelihood of response based on patient and family characteristics; then this model was used to apply weights that were equivalent to the inverse of the probability of response for that individual.

Results: Interviews were completed with family members of 3,897 of 7,110 patients (55%). Once results were weighted to account for nonresponse bias, the change in mean individual scores was 2% of families reporting "excellent" care. Of the 62 facilities in the sample, the scores of only 19 facilities (31%) changed more than 1% in either direction, and only 10 (16%) changed more than 2%.

Conclusion: Although nonresponse bias is a theoretical concern, it does not appear to have a significant effect on the facility-level results of this retrospective family survey.