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

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.