Clinical Characteristics of Chronic Pancreatitis Patients Presenting With Acute Pancreatitis, Abdominal Pain, or Primary Painless Disease

Background: – Acute pancreatitis (AP) or abdominal pain does not always precede chronic pancreatitis (CP), but prevalence estimates from prior studies utilized variable definitions of CP. We aimed to examine the clinical characteristics of CP patients presenting with and without AP or abdominal pain. Methods: – The records of consecutive patients with definite CP per the M-ANNHEIM criteria between 2010 and 2023 were reviewed. AP was defined as per the revised Atlanta classification. AP preceding or concurrent with CP was defined as a diagnosis of CP >1 or ≤1 year after an index episode of AP, respectively. Painful CP was defined as a presentation with abdominal pain but without a history of AP. Primary painless CP was defined as having no history of abdominal pain or AP. Results: – Among a total of 548 CP patients, 306 (55.8%) had AP preceding CP, 96 (17.5%) had AP concurrent with CP, 100 (18.2%) had painful CP, and 46 (8.4%) had primary painless CP. The median time from index AP and onset of abdominal pain to a CP diagnosis was 4.67 [1.45, 7.89] years and 5.0 [1, 16.5] months, respectively. Smoking-only etiology of CP was 3 times more prevalent in AP concurrent with CP compared with AP preceding CP (20.8% vs. 7.5%, P<0.001). AP preceding or concurrent with CP compared with the painful and primary painless CP was more prevalent in those with an alcohol etiology (38%, 28% vs. 20%, P=0.01) and in younger patients (49.4±15.4, 57.5±13.4 vs. 70.0±10.1 y, P<0.001). Primary painless CP was found more frequently in patients with advanced age (70.0±10.1 y), male gender (66.7%), and an idiopathic etiology (50.0%) compared with all of the other groups (P<0.05). Conclusion: – Preceding or concurrent AP is found in nearly 75% of patients with definite CP by the M-ANNHEIM classification. Pain-only presentations are seen in 20% of patients with definite CP. Age of disease onset and etiology have a significant impact on the clinical presentation of CP patients.