Serum Phosphate is a Biomarker for In-hospital and 30-day Mortality in Patients With Acute Pancreatitis Based on the MIMIC-IV Database.

Background: Acute pancreatitis (AP) is the most common disease in emergency and intensive care units; early mortality predictions and intervention are crucial for improving patient prognosis. We investigated the association of serum phosphate with mortality among AP patients using a large public database.

Methods: This was a retrospective study. All AP patients in the MIMIC-IV database were included. Based on the tertiles of serum phosphate, all AP patients were divided into 3 groups. Two generalized additive models were performed to explore the association of serum phosphate with in-hospital and 30-day mortality. Kaplan-Meier analysis was introduced for survival probability.

Results: A total of 1088 AP patients admitted to the ICU were included. The mortalities of in-hospital (n=137) and 30-day (n=118) were 12.59% and 10.85%, respectively. The median levels of serum phosphate in the survivor and the non-survivor groups were 3.20 and 3.90 mg/dL, respectively (P<0.001). After adjusting for all potential confounders, with 1 mg/dL increment in serum phosphate, the risk of in-hospital and 30-day mortality increased by 20% (HR=1.20, 95% CI: 1.00-1.44, P=0.0443) and 25% (HR=1.25, 95% CI: 1.03-1.52, P=0.0214), respectively. The areas under the ROC curve (AUC) of serum phosphate for predicting in-hospital and 30-day mortality were 0.650 (95% CI: 0.599-0.701) and 0.659 (95% CI: 0.605-0.714), respectively. The cutoff values of serum phosphate were 3.65 and 4.35 mg/dL, respectively.

Conclusions: A linear positive relationship was found between serum phosphate and in-hospital and 30-day mortality in AP. Serum phosphate was associated with in-hospital and 30-day mortality in AP. Our results could be used for screening out those AP patients with a higher risk of worse outcomes.