Prospective Validation and Clinical Implementation of the FLHAS Score in Patients Presenting with Hemoptysis to the Emergency Department

Background Hemoptysis is a potentially life-threatening symptom that often prompts emergency department (ED) evaluation and hospitalization. Reliable prognostic tools to guide clinical decision-making and optimize resource use are currently lacking. Objective To prospectively validate the Florence Hemoptysis Assessment Score (FLHASc) in patients presenting with hemoptysis to the ED, and to eventually derive and validate an improved version of the score (FLHASc2). Methods We analyzed data from the POPEIHE study (NCT06067997), a multicenter prospective cohort of 546 consecutive adult patients presenting with hemoptysis to nine Italian EDs. The primary outcome was a composite of in-hospital death, need for ventilatory support, intensive care unit (ICU) admission, blood transfusion, or invasive hemostatic procedures. We evaluated the prognostic performance of the original FLHASc, then derived a new model (FLHASc2) using multivariate logistic regression in a derivation cohort (n=321), and validated it in a separate validation cohort (n=225). A simplified version of the score was also tested. Results The original FLHASc demonstrated moderate discriminatory ability (AUC 0.71; 95% CI: 0.62–0.79) but was poorly calibrated. The FLHASc2 showed improved performance (AUC 0.79, 95% CI: 0.73–0.87 in derivation and 0.81, 95% CI: 0.73–0.88, in validation cohorts; Brier score <0.10 in both). The simplified FLHASc2 (sFLHASc2), assigning one point per variable, maintained comparable accuracy (AUC 0.81, 95% CI: 0.74–0.89) and identified 47.9% of patients as low risk (2.7% event rate). When combined with a negative chest X-ray, the observed event rate in this subgroup dropped to 0.87%, with a negative predictive value of 99.1% (CI 95%, 96.5-100%). Conclusions The FLHASc2 and its simplified version are accurate prognostic tools for identifying hemoptysis patients at low risk of short-term adverse outcomes. Use of the sFLHASc2 combined with chest X-ray may allow safe ED discharge in nearly half of cases. A prospective management trial is warranted to confirm its clinical impact.