Factors Related to Development of Pancreatic Adenocarcinoma in Patients With Chronic Pancreatitis on Long-term Follow-up: A Database Study

BACKGROUND: Chronic pancreatitis (CP) is a risk factor for pancreatic adenocarcinoma (PA). However, little is known about factors related to development of PA in CP. OBJECTIVE: To evaluate factors associated with PA in CP. METHODS: A national insurance database of 120 million US patients was used. Adults with an International Classification of Diseases, Ninth Revision (ICD-9) code for CP (577.1) from January 1, 2009, to December 31, 20014, were identified. Patients' age, sex, and ICD-9 codes for PA, bile duct obstruction, alcohol use, diabetes mellitus before and after diagnosis of CP, obesity, tobacco use, and type of insurance were obtained. Patients with CP without a unique identification number, missing dates for insurance coverage period, and with duration to end of follow-up or development of PA less than 2 years were excluded. The Cox proportional hazards regression model was used for analysis. RESULTS: The final analysis had 30,555 patients with CP including 219 patients (0.72%) with PA. The Cox proportional hazards regression model showed that in patients with CP age (hazard ratio [HR] = 1.07; 95% Confidence Interval [CI] = 1.03-1.1), male sex (HR = 2.1; 95% CI = 1.25-3.54), tobacco use (HR = 1.88; 95% CI = 1.1-3.23), and having commercial insurance (HR = 4.26; 95% CI = 1.63-11.11) were associated with a subsequent medical claim for PA. Duration of bile duct obstruction (HR = 0.999; 95% CI = 0.998-0.999) and presence of diabetes mellitus before CP (HR = 0.35; 95% CI = 0.19-0.63) were inversely related to subsequent diagnosis of PA. CONCLUSION: PA was diagnosed in 0.72% of the patients with CP at least 2 years after the diagnosis of CP. Increasing age, male sex, tobacco use, having commercial insurance, absence of diabetes mellitus before CP, and shorter duration of bile duct obstruction were associated with a diagnosis of PA in patients with CP.