Background: The ECOG performance status (PS) scale was developed to support national clinical trials, but the degree to which ECOG PS predicts clinical outcomes in patient subgroups outside of clinical trials is relatively unknown. This study examined associations between ECOG PS and adverse outcomes in a diverse community oncology population.

Patients and Methods: In this retrospective cohort study, demographic and clinical characteristics, including the most recent ECOG PS between January 1, 2017, and December 31, 2019, were examined for patients receiving cancer treatment within Kaiser Permanente Northern California (KPNC). Proportional hazard models were used to evaluate the effect of ECOG PS on adverse outcomes.

Results: A total of 21,730 patients were identified. Overall, most patients had an ECOG PS of 0 (42.5%) or 1 (42.5%). In multivariable analysis, an ECOG PS of 3 or 4 was associated with higher risk of 30-day emergency department visits (adjusted hazard ratio [aHR], 3.85; 95% CI, 3.47–4.26), 30-day hospitalizations (aHR, 4.70; 95% CI,
4.12–5.36), and 6-month mortality (aHR, 7.34; 95% CI, 6.64–8.11) compared with an ECOG PS of 0. Additionally, we found that upper gastrointestinal and stage IV cancers were associated with a higher risk of adverse outcomes compared with breast and stage I cancers, respectively. When adjusted for ECOG PS, African American race, Asian race, and female sex were associated with a lower risk of mortality than White race and male sex. An ECOG PS of 3 or 4 was more predictive of mortality in younger patients and those with breast cancer (P ,.001).

Conclusions: ECOG PS and upper gastrointestinal and stage IV cancers were independently associated with increased risk of emergency department visits, hospitalizations, and mortality, whereas African American and Asian race and female sex were associated with decreased risk of mortality. An ECOG PS of 3 or 4 was more predictive of an increased risk of mortality in younger patients and patients with breast cancer. These findings can enhance the use of ECOG PS for clinical decision-making and defining eligibility for clinical trials.