The malaria severity score: a method for severity assessment and risk prediction of hospital mortality for falciparum malaria in adults.

BACKGROUND There is paucity of research to quantify the severity and to predict the mortality risk of severe falciparum malaria even if it affects multiple organ systems during the course of the disease. Therefore, the aim of the present study is to develop a severity score for assessment of disease severity and risk prediction in adult patients of severe falciparum malaria on the first day of hospitalisation. METHODS A cohort of 2598 patients of falciparum malaria were enrolled in this study of which 2089 patients were included as developmental sample and 509 patients as validation sample. Physiological variables were analyzed for defining and assessment of severity of organ dysfunction (OD). The severity level and corresponding severity score for each organ dysfunction were determined by logistic regression analysis that took both the relative severity among the organ systems and the degree of severity within an organ system into account. Risk of mortality has been calculated for each score. RESULTS Physiological variables defined dysfunction in 7 organ systems with 3 levels of severity (I to III). Neurologic and renal dysfunction had 3 levels of severity. Hematologic, cardiovascular, and respiratory dysfunction had 2 levels of severity where as hepatic and metabolic dysfunction had 1 level of severity. 1,3, and 5 points were assigned to level I, II, and III severity of organ dysfunction respectively. Malaria without any abnormal physiological variables had been considered as no organ failure and assigned 0 score. The cumulative scores in a patient is known as malaria severity score (MSS) that ranged from 0 to 21. Risk of mortality had been calculated for each score. CONCLUSION This prospective study provides an objective tool for assessing severity levels for organ dysfunction and prediction of risk of mortality in severe falciparum malaria which can be used for treatment and research. It has been observed that no two patients of falciparum malaria are same in severity. The severity varies over time and malaria can affect single or multiple organs with different levels of severity which can be quantified as level I, II, and III. Neurologic and renal dysfunction were the most severe with level III severity, followed by haematologic, cardiovascular, and respiratory dysfunction with level-II severity, as well as hepatic and metabolic dysfunction the least severe with level-I severity. Patient of malaria can be stratified as low, intermediate, and high risk depending on the MSS. With the help of MSS daily risk estimates and recovery time of OD can be determined.