To the Editor We have read with great interest the retrospective population-based cohort study by Sullivan et al.1 They found an association of early palliative care (received 0 to 30 days after cancer diagnosis) with decreased survival (adjusted hazard ratio, 2.13; 95% CI, 1.97-2.30) in patients with advanced lung cancer.
The authors used the propensity score method for reduction of selection bias among groups. The propensity score included factors such as the Charlson Comorbidity Index score and the Functional Comorbidity Index score. However, these parameters do not represent the true performance status of patients. Performance status is one of the major factors in cancer treatment decision-making and is assessed using the Eastern Cooperative Oncology Group scale2 or the Karnofsky scale.3 In addition, performance status is also associated with specialists’ decisions to deliver palliative care. Therefore, patients with greater functional impairment are more likely to receive palliative care sooner.