Despite the high mortality and morbidity associated with hyperglycemic emergencies (HEs), reliable biological markers that could predict the severity and prognosis are largely unavailable. This study therefore, assessed the performance of copeptin in predicting the severity and prognosis of HEs. Sixty patients with HEs [27 with diabetes ketoacidosis (DKA) and 33 with hyperglycemic hyperosmolar state (HHS)] were recruited into this cross-sectional study. Serum copeptin was determined using ELISA. Glasgow Coma Scale (GCS) was used to grade the severity of HE and the performance of copeptin in predicting the severity of HE was determined using the Area under the Receiver Operating Characteristic Curve (AUROC). Data analysis was done using the Student’s t-test, Mann Whitney U and Spearman correlation as appropriate. P<0.05 was considered as statistically significant. The median copeptin level was slightly higher in patients with HHS than in patients with DKA. In patients with moderately severe score of GCS (GMo), the median copeptin level was significantly higher when compared with patients with normal GCS score (GN). Assessing the performance of copeptin in predicting the severity of HE, copeptin had AUROC of 6.334 (P = 0.034) for GN and 0.738 (P = 0.011) for GMo. During the study, 10 patients (16.7%) died but the median copeptin level was only slightly higher in the patients that died (PD) than in patients that survived (PS). Also, the median copeptin level in patients who survived and were on admission for ≥ 11 days was slightly higher than in those that were admitted for ≤ 10 days. There was a significant inverse correlation between copeptin and GCS scores. Copeptin might not be a good prognostic marker in patients with hyperglycemic emergencies but had good performance in predicting patients with hyperglycemic emergencies with normal and moderately severe GCS scores
