Abstract / Summary
Abstract Although previous studies have demonstrated comparable predictive performance between shock index (SI) and simple shock index (sSI), the practical aspects of sSI has not been evaluated. This study aimed to compare the classification accuracy, assessment time, and preference of SI and sSI. This randomized-order within-participant repeated-measures simulation study included fifth-year medical students at a single university from 2025 to 2026. Participants assessed 10 clinical cases using SI and sSI and classified each case as high or low risk. Classification accuracy and assessment time were analyzed using participant-level paired analyses. Preference was evaluated using a three-category questionnaire (sSI, SI, or no difference). Eighty-seven students participated in the study. Classification accuracy was 93.3% for sSI and 94.0% for SI, with no significant difference between the two methods (difference, − 0.7% points; 95% confidence interval [CI], − 4.1 to 2.8; P = 0.629). Assessment time using sSI was shorter than that using SI in the primary analysis (median, 7.6 vs. 8.3 s; median difference, − 0.9 s; 95% CI, − 1.6 to − 0.5; P = 0.002). Regarding preference, 57 participants preferred sSI, 18 preferred SI, and 12 reported no preference; among participants who expressed a preference for either method, sSI was preferred significantly more often than SI ( P < 0.001). In this exploratory study, no statistically significant difference in classification accuracy or practically meaningful difference in assessment time was observed between sSI and SI, although participants preferred sSI. Further studies are needed to determine whether these findings translate into clinically meaningful advantages.