Trajectories of Pain Processing in Recurrent Acute and Chronic Pancreatitis: A Longitudinal Quantitative Sensory Testing Study

Background: Recurrent acute and chronic pancreatitis are often associated with severe abdominal pain. Notably, the presence and intensity of pain often show little correlation with structural pancreatic changes, suggesting a role for altered peripheral and central pain processing. To investigate these mechanisms, a pancreas-specific quantitative sensory testing protocol (P-QST) has been developed to characterise pain processing. However, how P-QST patterns evolve over time remains unclear. Methods: We conducted a three-year prospective observational study at two Danish hospitals, enrolling patients with recurrent acute or chronic pancreatitis. Participants underwent annual P-QST assessments and filled in questionnaires focused on clinical pain and life quality. P-QST phenotypes were classified into P-QST subgroups based on established normative criteria: (i) no hyperalgesia, (ii) segmental hyperalgesia, or (iii) widespread hyperalgesia. Changes in P-QST phenotypes were investigated over time, and their associations with patient-reported outcomes were examined. Results: Eighty-four patients were included (35 recurrent acute pancreatitis and 49 chronic pancreatitis). The mean age was 48.8 years, and 71% were male. At baseline, 47 (56%) had no hyperalgesia, 21 (25%) had segmental hyperalgesia, and 16 (19%) had widespread hyperalgesia. P-QST phenotypes changed in 46% of patients within the first year; 23% improved (less hyperalgesia), and 23% worsened (worse hyperalgesia). Patients with worsening hyperalgesia reported greater declines in quality of life and greater increases in pain interference scores than those with stable or improving P-QST phenotypes (all p < 0.03). Conclusion: P-QST phenotypes in recurrent acute and chronic pancreatitis are dynamic and associated with pain and quality of life outcomes. Significance Statement: Pain in recurrent acute pancreatitis and chronic pancreatitis often cannot be explained by structural pancreatic changes, indicating altered pain processing. This prospective three-year study demonstrates that pancreas-specific quantitative sensory testing (P-QST) phenotypes are dynamic rather than stable traits. Importantly, changes in P-QST phenotypes were associated with clinically meaningful changes in pain interference and quality of life. These findings support longitudinal assessment of pain processing and highlight P-QST as a potential tool for phenotyping pain.