Psoas muscle size as a magnetic resonance imaging biomarker of progression of pancreatitis.

• First acute pancreatitis, recurrent acute pancreatitis, and chronic pancreatitis were associated with progressively reduced psoas muscle size. • The findings were independent of age, sex, body fat composition, physical activity, tobacco smoking, alcohol consumption, comorbidities, and exocrine and endocrine functions of the pancreas. • The mechanism underlying the observed findings may involve hyperleptinaemia.