The Metabolic Legacy of Acute Pancreatitis: Post-Pancreatitis Diabetes Mellitus.

Post-pancreatitis diabetes mellitus after acute pancreatitis (PPDM-A) is increasingly recognized as a distinct metabolic complication rather than a simple subtype of type 2 diabetes. This narrative review summarizes current evidence on PPDM-A, with emphasis on terminology, diagnostic timing, epidemiology, pathophysiology, risk factors, clinical phenotypes, screening, prevention, and long-term follow-up. A structured literature search was conducted in PubMed/MEDLINE, Scopus, and Google Scholar to identify relevant studies. PPDM-A may develop after mild, moderately severe, or severe acute pancreatitis, although the risk is greatest in patients with pancreatic necrosis, recurrent attacks, exocrine pancreatic dysfunction, obesity, dyslipidemia, fatty liver disease, metabolic comorbidities, and marked in-hospital glycemic variability. A major diagnostic challenge is distinguishing transient stress hyperglycemia and previously unrecognized diabetes from incident PPDM-A. Formal diagnosis should generally be established no earlier than 90 days after the index episode of acute pancreatitis to minimize misclassification due to transient stress-related dysglycemia. Follow-up assessment should combine fasting plasma glucose and HbA1c, whereas a 75-g oral glucose tolerance test (OGTT) may provide greater sensitivity during early recovery, particularly when HbA1c is unreliable, results are borderline or discordant, or isolated postprandial dysglycemia is suspected. Current evidence indicates that PPDM-A develops through interacting pathogenic domains, including pancreatic endocrine injury with impaired β-cell reserve, metabolic dysregulation characterized by insulin resistance and persistent inflammation, exocrine pancreatic dysfunction with nutritional consequences, and emerging mechanisms involving gut microbiome alterations, bile acid-FGF19 signaling, and extracellular vesicle-mediated communication. Available data support a trajectory-based model in which some patients recover normal glucose metabolism, some develop persistent intermediate dysglycemia, and others progress to overt diabetes over months or years. Structured post-discharge surveillance, risk-stratified follow-up, assessment of exocrine dysfunction, and prevention of recurrent pancreatic injury are essential for improving early detection, reducing diagnostic misclassification, and optimizing long-term clinical outcomes.