Validation of the SPiRO Score for the Prediction of ICU Admission in Patients Presenting With Leptospirosis in Tropical Australia

OBJECTIVES: In some resource-limited settings the case-fatality rate of severe leptospirosis can exceed 50%. Early recognition of severe disease can expedite transfer to referral centres for advanced supportive care. The entirely clinical, 3-point SPiRO score can be calculated rapidly at presentation to predict a patient's subsequent clinical course. In its derivation study, a SPiRO score of 0 had a negative predictive value (NPV) for intensive care unit (ICU) admission of 98% (95% confidence interval [CI]: 96-99). In this validation cohort we sought to confirm the SPiRO score's prognostic utility and to compare its performance to other leptospirosis-specific and general disease severity scores. METHODS: We examined consecutive adults presenting to four high-caseload hospitals in tropical Australia with laboratory-confirmed leptospirosis between June 2016 and April 2026. The SPiRO score's ability to predict ICU admission before hospital discharge was compared with that of the leptospirosis-specific QuickLepto score and commonly used disease severity scores, namely the SOFA, qSOFA, qSOFA-lactate, NEWS-2, qNEWS, UVA and the SIRS scores. RESULTS: There were no deaths in 309 episodes of leptospirosis, but in 62 (20%) there was an ICU admission. The SPiRO score performed as well as, or better than, all the other scores in predicting ICU admission. The area under the receiver operating characteristic curve for the SPiRO score was 0.83 (95% CI: 0.77-0.89); only the SOFA score had a higher value: 0.84 (0.79-0.90), although the difference was not statistically significant (p = 0.08). The SPiRO score had the highest NPV for ICU admission of any of the scores: 95 (95% CI: 91-97)%. CONCLUSIONS: The SPiRO score can be calculated easily at the bedside at presentation to expedite the recognition of patients with leptospirosis who are most likely to deteriorate. In resource-limited settings this entirely clinical score can also help reduce unnecessary escalation of care, optimising the use of finite health resources.