Nurse and physician inter-rater agreement of three performance status measures in palliative care outpatients.

INTRODUCTION: Performance status (PS) scales are used widely in oncology practice and research. We compared inter-rater agreement, between nurses and physicians, for three commonly used PS scales.
MATERIALS AND METHODS: Patients attending an oncology palliative care clinic were assessed by a physician and nurse who blindly completed Eastern Cooperative Oncology Group (ECOG), Karnofsky PS (KPS), and palliative PS (PPS) scales. Patients completed the Edmonton symptom assessment system (ESAS).
RESULTS: Inter-rater agreement (weighted kappa) for the 457 patients was 0.67 for the ECOG, 0.74 for the KPS, and 0.72 for the PPS. There was no difference between proportions of physicians' vs. nurses' ratings of KPS, >60 vs. <or=60 (McNemar's test, p = 0.33); however, physicians were more likely to rate patients as having better PS for the ECOG (77% in the 0-2 range vs. 70% for nurses, p = 0.0003) and PPS (63% in the 70-100 range vs. 54% for nurses, p = 0.0001). Physician and nurse scores of ECOG, KPS, and PPS were all correlated with ESAS distress score (Pearson correlation, r = 0.4-0.5).
CONCLUSIONS: Although inter-rater agreement was good for all three scales, physicians tended to rate patients as healthier for the PPS and ECOG. The KPS may provide greater consistency of PS ratings by different oncology professionals in clinical and research settings.