Natural History, Clinical Characteristics, and Outcomes in Idiopathic Chronic Pancreatitis

Background and Aims: Chronic pancreatitis (CP) is a fibroinflammatory syndrome of the pancreas associated with pain and poor quality of life. It has toxic and genetic risk factors but can also be idiopathic. The natural history of idiopathic CP (ICP) is not well-known. Therefore, we studied clinical characteristics and outcomes of these patients followed in our Pancreas Center. Methods: Review of CP patients between January 1, 2016, and April 30, 2021. Patients were divided into 2 groups based on diagnosis, ICP vs non-ICP. CP patients with a smoking history were placed in the non-ICP group. Statistical analysis was performed to identify differences in demographics, comorbidities, complications, controlled medications, and resource utilization. Results: Out of 450 patients, 101 (22%) were diagnosed with ICP and 349 (78%) were non-ICP. ICP patients were mainly female (59.4% vs 40.5%; P = .005), had less comorbid anxiety (10.5% vs 22.1%; P = .002), depression (24.2% vs 35.8%; P < .001), disability (13% vs 16.3%; P = .021), exocrine pancreatic insufficiency (45.3% vs 62.6%; P = .004), splanchnic vein thrombosis (1.04% vs 14.9%; P < .001), pseudocysts (16.7% vs 41.6%; P < .001), and biliary obstruction (3.12% vs 19.2%; P < .001). They underwent less abdominal imaging (2.63 vs 3.42; P = .048) and endoscopic retrograde cholangiopancreatography (0.88 vs 1.32; P = .030). They also had less opioid use (29.6% vs 54.4%; P < .001), gabapentinoid use (34% vs 52.3%; P = .002), and celiac blocks (7.22% vs 16.1%; P < .041). Conclusion: Our study demonstrates that the clinical course of ICP is less morbid compared to non-ICP. This study specifically removes smoking, a significant risk factor for CP, to study a truly idiopathic cohort.