Overlap and cumulative effects of pancreatic duct obstruction, abnormal pain processing and psychological distress on patient-reported outcomes in chronic pancreatitis

OBJECTIVE: Several factors have been suggested to mediate pain in patients with chronic pancreatitis. However, it is unknown whether these factors are overlapping and if they have cumulative effects on patient-reported outcomes (PROs). DESIGN: We performed a multicentre cross-sectional study of 201 prospectively enrolled subjects with definitive chronic pancreatitis. All subjects underwent evaluation for pancreatic duct obstruction, abnormalities in pain processing using quantitative sensory testing, and screening for psychological distress (anxiety, depression and pain catastrophising) based on validated questionnaires. Abnormality was defined by normal reference values. PROs included pain symptom severity (Brief Pain Inventory short form) and quality of life (EORTC-QLQ-C30 questionnaire). Associations between pain-related factors and PROs were investigated by linear trend analyses, multiple regression models and mediation analyses. RESULTS: Clinical evaluation suggestive of pancreatic duct obstruction was observed in 29%, abnormal pain processing in 23%, anxiety in 47%, depression in 39% and pain catastrophising in 28%; each of these factors was associated with severity of at least one PRO. Two or more factors were present in 51% of subjects. With an increasing number of factors, there was an increase in pain severity scores (p<0.001) and pain interference scores (p<0.001), and a reduction in quality of life (p<0.001). All factors had independent and direct effects on PROs, with the strongest effect size observed for psychological distress. CONCLUSION: Pain-related factors in chronic pancreatitis are often present in an overlapping manner and have a cumulative detrimental effect on PROs. These findings support a multidisciplinary strategy for pain management. TRIAL REGISTRATION NUMBER: The study was registered with ClinicalTrials.gov (NCT03434392).