Customization and external validation of the Simplified Mortality Score for the Intensive Care Unit (SMS-ICU) in Brazilian critically ill patients

• Published in: Journal of critical care Vol. 59; pp. 94 - 100
• Main Authors: Zampieri, Fernando G., Granholm, Anders, Møller, Morten Hylander, Scotti, Alexandre Vaz, Alves, Alessandra, Cabral, Maurício Magalhães, Sousa, Marcelo Ferreira, Balieiro, Henrique Miller, Hortala, Carlos Cesar, Filho, Edison Moraes Rodrigues, Perecmanis, Eric, de Magalhães Menezes, Márcia Adélia, Moreira, Carlos Eduardo Nassif, Moralez, Giulliana Martines, Bafi, Antônio Tonete, de Carvalho, Clayton Barbieri, Salluh, Jorge Ibrain Figueira, Bozza, Fernando Augusto, Perner, Anders, Soares, Marcio
• Format: Journal Article
• Language: English
• Published: United States Elsevier Inc 01-10-2020; Elsevier Limited
• Subjects: Blood pressure; Calibration; Critical care; Customization; Data collection; Heart rate; Hospitals; Illness severity scores; Illnesses; Intensive care; Laboratories; Mortality; Outcome; Physiology; Variables; Ventilators; Brazil; Illness severity scores; Critical care; Outcome
• DOI: 10.1016/j.jcrc.2020.05.016
• EISSN: 1557-8615
• ISSN: 0883-9441

To customize and externally validate the recently proposed Simplified Mortality Score for the ICU (SMS-ICU, a simple score for 90-day mortality that has no need for ancillary testing results) for in-hospital mortality and to compare its performance to SAPS 3.
We used data from two distinct large cohorts of adult Brazilian patients with unplanned ICU admissions to perform a first-level customization (43,017 patients admitted to 78 ICUs) of the original SMS-ICU score for in-hospital mortality and, sequentially, externally validate it (313,365 patients admitted to 99 ICUs). Performance of SMS-ICU was assessed through measurements of discrimination and calibration and compared with SAPS 3.
In the validation cohort, median SMS-ICU was 13 (IQR 8–16) points and median SAPS 3 was 44 (IQR 36–51). Discrimination of SMS-ICU was good (AUC 0.817; 95% CI 0.814–0.819) but slightly lower than of SAPS 3 (AUC 0.845; 95% CI 0.843–0.848;). The customized SMS-ICU predictions were comparable to SAPS 3 in terms of calibration.
In this external validation of the SMS-ICU in a large Brazilian cohort, we observed good discrimination of SMS-ICU and acceptable calibration after first-level customization. SMS-ICU can be used as a measure of illness severity for acutely admitted ICU patients in clinical studies.
•Severity scores usually require laboratory data, which may result in missing values and increase burden of data collection•A simple illness severity score of seven variables (SMS-ICU) has good discrimination and acceptable calibration in a large cohort of critically ill patients•SMS-ICU could be used as an alternative to traditional illness severity scores specially in the context of clinical studies