Comparison of lipase/amylase ratio in biliary and non-biliary acute pancreatitis patients

Objective: Acute pancreatitis is a common inflammatory condition of the pancreas, clinically characterized by abdominal pain and elevated pancreatic enzyme levels in the blood. A number of conditions are known to induce this disorder with varying degrees of certainty. However, the pathogenesis of this disorder is not yet fully understood. The incidence of acute pancreatitis is increasing worldwide due to rising obesity and gallstone rates. Gallstones are the most common cause of acute pancreatitis, accounting for 40% to 70% of cases. However, only 3% to 7% of patients with gallstones develop pancreatitis. The mechanism by which the passage of gallstones causes pancreatitis is unknown. Cholecystectomy and the clearance of stones from the common bile duct prevent recurrence, confirming the cause-and-effect relationship. Serum amylase increases within 6 to 12 hours after the onset of acute pancreatitis. A serum amylase elevation greater than three times the upper limit of normal has a sensitivity of 67% to 83% and a specificity of 85% to 98% for the diagnosis of acute pancreatitis. Serum lipase rises within 4 to 8 hours after symptom onset, peaks at 4 hours, and returns to normal within 8 to 14 days. Serum lipase has a sensitivity ranging from 82% to 100% for acute pancreatitis (AP). It is well known that amylase and lipase levels are the most critical factors in diagnosing pancreatitis. Regardless of etiology, these levels are typically elevated. Furthermore, the potential use of these levels for determining etiology has been a subject of concern. Gumaste et al. found that the lipase/amylase ratio could be used to distinguish between alcoholic and non-alcoholic acute pancreatitis. In our study, we aimed to determine the utility of the lipase/amylase ratio in differentiating biliary and non-biliary etiologies in patients hospitalized for acute pancreatitis. Materials and Methods: Patients diagnosed with acute pancreatitis at Afyonkarahisar Health Sciences University Hospital between January 2020 and December 2024 were included in the study. The data of these patients were reviewed from the hospital's electronic record system. Lipase and amylase values at the time of diagnosis were compared between biliary and non-biliary etiologies. Statistical analyses were performed using the SPSS version 27.0.1 software package. Results: In our study, a total of 109 patients were evaluated, including 65 males (59.6%) and 44 females (40.4%). The median age of the patients was 59 years (min-max = 18-89 years). While 49.5% (n = 54) of the patients were hospitalized due to biliary pancreatitis, 50.5% (n = 55) were hospitalized for non-biliary pancreatitis. In the biliary pancreatitis group, lymphocyte count and 48-hour BUN levels were found to be significantly lower compared to the non-biliary pancreatitis group (p = 0.002 and p = 0.044, respectively), whereas amylase, LDH, AST, and Ranson scores were significantly higher (p = 0.028, p = 0.010, p<0.001, and p = 0.005, respectively). Other parameters were found to be similar between the two groups. The biliary and non-biliary pancreatitis groups were also found to be similar in terms of the lipase/amylase ratio (p = 0.388). A lipase threshold of 639 was found to predict biliary pancreatitis with a sensitivity of 79.6% and a specificity of 43.6%, while an amylase threshold of 252.5 was found to predict biliary pancreatitis with a sensitivity of 88.9% and a specificity of 38.2%. Conclusion: In our study, it was determined that the lipase/amylase ratio was similar in patients with biliary and non-biliary acute pancreatitis and could not be used to distinguish between these two groups. Separate evaluation of serum amylase and lipase levels may be beneficial in predicting biliary pancreatitis. Further large-scale, multicenter, and comprehensive prospective studies are needed to support this approach. Keywords: Acute Pancreatitis, Amylase, Biliary and Non-Biliary Pancreatitis, Lipase, Lipase/Amylase Ratio