Uncooperative patients suspected of acute stroke ineligible for prehospital stroke screening test by emergency medical service providers: final hospital diagnoses and characteristics

Objective This study investigated the hospital diagnoses and characteristics of uncooperative prehospital patients suspected of acute stroke who could not undergo a prehospital stroke screening test (PHSST). Methods This retrospective observational study was conducted at a single academic hospital with a regional stroke center. We analyzed three scenario-based prehospital stroke screening performances using the final hospital diagnoses: (1) a conservative approach only in patients who underwent the PHSST, (2) a real-world approach that considered all uncooperative patients as screening positive, and (3) a contrapositive approach that all uncooperative patients were considered as negative. Results Of the 2,836 emergency medical services (EMS)-transported adult patients who met the prehospital criteria for suspicion of acute stroke, 486 (17.1%) were uncooperative, and 570 (20.1%) had a confirmed final diagnosis of acute stroke. The diagnosis in the uncooperative group did not differ from that in the cooperative group (22.0% vs. 19.7%, P = 0.246). The diagnostic performances of the PHSST in the conservative approach were as follows: 79.5% sensitivity (95% confidence interval [CI], 75.5%-83.1%), 90.2% specificity (95% CI, 88.8%-91.6%), and 0.849 area under the receiver operating characteristic curve (AUC; 95% CI, 0.829-0.868). The sensitivity and specificity were 83.3% (95% CI, 80.0%-86.3%) and 75.2% (95% CI, 73.3%-76.9%), respectively, in the real-world approach and 64.6% (95% CI, 60.5%-68.5%) and 91.9% (95% CI, 90.7%-93.0%), respectively, in the contrapositive approach. No significant difference was evident in the AUC between the real-world approach and the contrapositive approach (0.792 [95% CI, 0.775-0.810] vs. 0.782 [95% CI, 0.762-0.803], P > 0.05). Conclusion We found overestimation (false positive) and underestimation (false negative) in the uncooperative group depending on the scenario-based EMS stroke screening policy for uncooperative prehospital patients suspected of acute stroke.