Predicting mortality in patients with malarial acute renal failure

Abstract

Acute Physiology and Chronic Health Evaluation (APACHE) III scores, calculated within the first 24 h of admission, were analysed in 108 patients with acute renal failure due to falciparum malaria who were admitted to Bangkok Hospital for Tropical Diseases, Thailand. Twelve (11.1%) patients died. The mean APACHE III score was 82.0 ± 25.5 (range, 45-171). There was a close relation between the APACHE III score and the hospital mortality rate. The non-survivors had significantly higher APACHE III scores than the survivors, 109±836.7 and 75.7±21.6, respectively (P<0.001). Patients with APACHE III score > 82 had a 4.2-fold higher risk of dying compared with patients with a lower score (95% CI 1.2-14.7; P=0.013). Haemodialysis treatment was performed in 97 (89.8%) of the patients. The mean APACHE III score for patients who were not treated with haemodialysis (95.9±38.0) was not significantly higher than those who received haemodialysis (80.4±23.5; P>0.05), but the former had a 4.4-times higher risk of dying compared with those dialysed (95% CI 1.6-12.3; P=0.019). Using the APACHE III score and its ability to predict death, we calculated its sensitivity, specificity and accuracy to be 0.92, 0.31 and 0.41, respectively, at a cut-off score of 67 points. The area under the receiver operating characteristic (ROC) curve was 0.75. The APACHE III scoring system correlated well with the outcome of critically ill malaria patients with acute renal failure, although it was not possible to identify individual survivors or non-survivors. APACHE III should not be used for individual prognosis or treatment decisions.