Significance of serum osmolarity in patients with acute pancreatitis

Approximately 15-25% of cases of acute pancreatitis follow a severe clinical course. Early identification of severe acute pancreatitis is crucial for predicting potential morbidity and mortality. This study aimed to evaluate the association between serum osmolarity and in-hospital mortality in acute pancreatitis patients.

Patients hospitalized with a diagnosis of acute pancreatitis between 1 January 2015 and 1 August 2019 in the Gastroenterology Service and Internal Medicine ICU in a tertiary center were analyzed retrospectively. A total of 311 patients were enrolled in the study. Demographic, clinical, laboratory, and radiological data, including calculated serum osmolarity values and their components, were analyzed based on acute pancreatitis morphological type, disease severity, in-hospital mortality, and ICU admission.

Admission serum osmolarity was significantly higher in patients with severe acute pancreatitis and those who required intensive care (P < 0.001 and P = 0.003, respectively). Admission osmolarity showed positive correlations with the Ranson score, length of stay, and high-sensitive C-reactive protein. The area under the curve (AUC) for serum osmolarity at 24 h was [AUC: 0.822, 95% confidence interval (CI): 0.728-0.921, P = 0.001], with a cut-off value of 295.69 mOsm/L (sensitivity: 60% and specificity: 90.4%). The AUC for serum osmolarity at 48 h (OSM48) was (AUC: 0.932, 95% CI: 0.815-0.976, P < 0.001), with a cut-off value of 296.67 mOsm/L (sensitivity: 70% and specificity: 94%). Each 1 mOsm/L increase in (OSM48) was associated with a 15.1% increase in the odds of in-hospital mortality.

Elevated serum osmolarity, measured at 48 h after admission, is a valuable and easily obtainable parameter and is related to in-hospital mortality in patients with acute pancreatitis.