Background The case-fatality rate of severe leptospirosis can exceed 50%. While prompt supportive care can improve survival, predicting those at risk of developing severe disease is challenging, particularly in settings with limited diagnostic support. Methodology/Principal findings We retrospectively identified all adults with laboratory-confirmed leptospirosis in Far North Queensland, Australia, between January 1998 and May 2016. Clinical, laboratory and radiological findings at presentation were correlated with the patients’ subsequent clinical course. Medical records were available in 402 patients; 50 (12%) had severe disease. The presence of oliguria (urine output ≤500 mL/24 hours, odds ratio (OR): 16.4, 95% confidence interval (CI): 6.9–38.8, p<0.001), abnormal auscultatory findings on respiratory examination (OR 11.2 (95% CI: 4.7–26.5, p<0.001) and hypotension (systolic blood pressure ≤100 mmHg, OR 4.3 (95% CI 1.7–10.7, p = 0.002) at presentation independently predicted severe disease. A three-point score (the SPiRO score) was devised using these three clinical variables, with one point awarded for each. A score could be calculated in 392 (98%) patients; the likelihood of severe disease rose incrementally: 8/287 (3%), 14/70 (20%), 18/26 (69%) and 9/9 (100%) for a score of 0, 1, 2 and 3 respectively (p = 0.0001). A SPiRO score <1 had a negative predictive value for severe disease of 97% (95% CI: 95–99%). Conclusions/Significance A simple, three-point clinical score can help clinicians rapidly identify patients at risk of developing severe leptospirosis, prompting early transfer to referral centres for advanced supportive care. This inexpensive, bedside assessment requires minimal training and may have significant utility in the resource-limited settings which bear the greatest burden of disease.

Many patients with leptospirosis, melioidosis, and rickettsial infection require intensive care unit (ICU) admission in tropical Australia every year. The multi-organ dysfunction associated with these infections results in significantly elevated severity of illness (SOI) scores. However, the accuracy of these SOI scores in predicting death from these tropical infections is incompletely defined. This retrospective study was performed at Cairns Hospital, a tertiary-referral hospital in tropical Australia. All patients admitted to ICU with laboratory-confirmed leptospirosis, melioidosis, and rickettsial disease between January 1, 1999 and June 30, 2020, were eligible for the study. The ability of Acute Physiology and Chronic Health Evaluation (APACHE) II, APACHE III, Simplified Acute Physiology Scores (SAPS) II, and Sequential Organ Failure Assessment (SOFA) scores to predict death before ICU discharge was evaluated. Overall, 18 (12.1%) of the 149 included patients died: 15/74 (20.3%) with melioidosis, 2/54 (3.7%) with leptospirosis and 1/21 (4.8%) with rickettsial disease. However, the APACHE II, APACHE III, SAPS II, and SOFA scores significantly overestimated the case-fatality rate of all the infections; the disparity between the predicted and observed mortality was most marked in the cases of leptospirosis and rickettsial disease. Commonly used SOI scores significantly overestimate the case-fatality rate of melioidosis, leptospirosis, and rickettsial infections in Australian ICU patients. This may be at least partly explained by the unique pathophysiology of these infections, particularly leptospirosis and rickettsial disease. However, SOI scores may still be useful in facilitating the comparison of disease severity in clinical trials that examine patients with these pathogens.

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