Expanding outpatient eligibility using a narrow definition of cancer in the Pulmonary Embolism Severity Index

Background: Guidelines recommend the Pulmonary Embolism (PE) Severity Index (PESI) or the simplified PESI (sPESI) to identify low-risk patients eligible for outpatient care. Cancer is a high-scoring variable in both scores, but definitions vary: "any" cancer (active/recent as well as remote/nonactive) vs "active" cancer (only active or recent). Objectives: This study evaluated the effect of narrowing the cancer definition (from any to active) on outpatient eligibility. Methods: We conducted a secondary analysis of a retrospective cohort study across 21 US community hospitals. Included were ambulatory adults diagnosed with PE in primary care who underwent vital sign measurements. Active-cancer PESI accrued cancer points only for metastatic disease or diagnosis, treatment, or palliative care within 12 months. We compared proportions of low-risk classification and 30-day adverse events (recurrent venous thromboembolism, major bleeding, and all-cause mortality) between any- and active-cancer definitions in both PESI and sPESI. Thirty-day outcomes among low-risk patients were rare (0.5%) and similar between groups. Conclusion: An active-only cancer definition (vs any cancer) in PESI and sPESI classified a larger proportion of PE patients as low risk. No differences in 30-day outcomes were observed in this very low-risk cohort. Studies in higher-risk cohorts are needed.