Objective: To measure the agreement between cancer patients' and family caregivers' perceptions of the patients' symptom severity, and the association between changes in caregiver accuracy and changes in outcomes.
Methods: Secondary analysis of baseline and 10-week follow-up data from 142 cancer patient/caregiver dyads. Patient/caregiver agreement about symptom burden was measured for the 8 most prevalent symptoms and overall. Bivariate analyses examined the patient and caregiver characteristics associated with caregivers who were overestimators, underestimators or accurate at baseline. We tested the relationship between change in caregiver accuracy and both caregiver behaviour (e.g. use of information, hours spent caregiving) and patient outcomes (e.g. total symptom severity and frequency).
Results: At baseline, caregivers overestimated the severity of 17 out of 18 symptoms; 50% predicted mean symptom severity accurately. Accuracy worsened over time for 51%, stayed the same for 36%, and improved for 13%. While not statistically significant, caregivers whose accuracy improved over time had patients who reported greater declines in: symptom severity, number of symptoms, symptom interference, total symptom frequency and depression. In addition, these caregivers experienced greater reductions in their use of information and hours helping the patient.
Discussion: Caregivers typically over-estimate cancer patients' symptom burden and accuracy does not improve over time. Improving caregiver accuracy may boost the positive effects of cognitive behavioural interventions designed to improve cancer patients' quality of life.