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 patients 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 clinical utility of the SPiRO score and to compare its prognostic utility with other leptospirosis-specific and general disease severity scores. Methods: We examined consecutive adults presenting to high-caseload hospitals in tropical Australia with laboratory-confirmed leptospirosis between June 2016 and April 2026. The ability of the SPiRO score to predict requirement for 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: ICU admission was required in 62/309 (20%) episodes of leptospirosis. 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.