Chronic inflammatory diseases and survival among patients with pancreatic cancer in the U.S. Military health system

Background: Systemic inflammation promotes the initiation and progression of pancreatic cancer, but the association between chronic inflammatory diseases and survival is less understood. This study aimed to investigate the relationship between chronic inflammatory diseases and survival among patients with pancreatic cancer in the US Military Health System (MHS), a healthcare system with universal access. Methods: The study utilized the Military Cancer Epidemiology database (MilCanEpi), a linked database comprising data from the Department of War's Central Cancer Registry (CCR) and the Military Health System (MHS) Data Repository (MDR). The diagnosis of chronic inflammatory diseases was queried in the MilCanEpi database. All-cause death was the study outcome. Multivariable time-dependent Cox proportional hazard regression was used to estimate hazard ratios (HRs) and 95% confidence interval (95% CI) of death associated with chronic inflammatory diseases. Results: Four hundred patients had chronic inflammatory diseases concurrent with or following their pancreatic cancer diagnosis, compared to 477 without such a diagnosis. There was a nearly two-fold increased risk of death associated with chronic inflammatory diseases after adjustment for confounders (adjusted HR = 1.77, 95% CI = 1.51-2.06). The association was observed in most subgroups defined by age, comorbidity, tumor stage, tumor grade, and time at diagnosis of chronic inflammatory diseases relative to pancreatic cancer diagnosis. Conclusion: Chronic inflammation, characterized by chronic inflammatory diseases, was independently associated with risk of increased all-cause death among patients with pancreatic cancer in the MHS.