Natural history, clinical characteristics, outcomes, and long-term follow-up of pain-free chronic pancreatitis

BACKGROUND: Chronic pancreatitis (CP) is characterized by chronic abdominal pain and functional insufficiency. However, a small subset of patients with prior acute pancreatitis (AP) and/or underlying risk factors for developing CP may be pain-free at diagnosis and may have a different clinical course. We aimed to compare the clinical characteristics, outcomes, and healthcare utilization between CP patients with and without pain. METHODS: Reviewed patients with established CP were followed in our Pancreas Center between January 2016 and April 2021. Patients without risk factors for developing CP and/or without AP prior to their diagnosis and only with incidental radiologic features of CP were excluded, so as to minimize confounding factors of pancreatopathy unrelated to CP. Patients were divided into painful and pain-free groups to analyze differences in demographics, outcomes, and healthcare utilization. RESULTS: Of 368 CP patients, 49 (13.3%) were pain-free at diagnosis and had remained so for >9 years. There were no significant differences in body mass index, race, sex, or co-morbidities between the two groups. Pain-free patients were older at diagnosis (53.9 vs 45.7, P = 0.004) and had less recurrent AP (RAP) (43.8% vs 72.5%, P < 0.001) and less exocrine pancreatic insufficiency (EPI) (34.7% vs 65.7%, P < 0.001). Pain-free patients had less disability (2.2% vs 22.0%, P = 0.003), mental illness (20.4% vs 61.0%, P < 0.001), surgery (0.0% vs 15.0%, P = 0.059), and therapeutic interventions (0.0% vs 16.4%, P = 0.005) for pain. CONCLUSIONS: We described a unique subset of patients with underlying risk factors for CP and/or prior AP who were pain-free at diagnosis. They were older at diagnosis, had less EPI and RAP, and overall favorable outcomes with minimal resource utilization.