Effect of Patient Factors and Quality of Life on ECOG Assignment and Inter-Rater Agreement in Hospitalized Cancer Patients

BACKGROUND: Assigning the ECOG performance status is critical for decision-making in oncology, but it poses challenges in hospitalized patients due to lower concordance and potential alteration by factors related to admission. This study aimed to evaluate the concordance of ECOG assessments among observers, identify associated factors with assignment, and explore its relationship with quality of life (QoL) in hospitalized oncology patients. METHODS: A prospective, observational study was conducted on patients admitted to a Medical Oncology Department. Three oncologists independently assessed the ECOG at admission, with a consensus value (ECOGa) being established. The EQ-5D-5L scale was administered within the first 48 hours. Linearly weighted Fleiss' Kappa (wFK) was used to assess concordance, and ordinal generalized linear mixed regression models were applied to analyze associated factors and to calculate values of model-based Kappa for agreement. RESULTS: A total of 167 patients were included, most of them (76%) with stage IV disease. Overall concordance was wFK 0.773 (95% CI 0.711-0.823). ECOGa was significantly associated with cancer stage (p = 0.03), reason for admission (p = 0.01), age (p = 0.04), and absence of active treatment (p = 0.01). The pain (p < 0.001) and self-care (p = 0.01) subscales of the EQ-5D-5L enhanced the prediction of ECOG performance status, outperforming models based on clinical model or QoL variables. Interobserver agreement, as determined by model-based kappa, was lower in the subgroup of patients with ECOGa = 2 and in patients admitted due to toxicity. CONCLUSIONS: Although ECOG assignment showed substantial concordance, both patient- and admission-related factors significantly influence its evaluation in hospitalized oncology patients. QoL measures may provide valuable complementary information for functional assessment in this population. A better understanding of the factors and clinical settings associated with lower interobserver agreement could help improve the functional assessment of cancer patients admitted to the hospital.