Short-term and long-term outcomes of autoimmune pancreatitis

To examine the short-term and long-term clinical courses of patients with autoimmune pancreatitis (AIP) who underwent different treatments and identify predictive factors for relapse of AIP after steroid therapy.

Clinical courses of 50 AIP patients followed up for more than 1 year (median 40 months, range: 12-173 months) were examined. Patients were subdivided according to initial treatments as follows: surgical procedures in 10 patients, supportive therapy in 11 patients, and steroid therapy in 29 patients.

Of the surgically treated patients, two underwent steroid therapy later because of progressive extensive lymphadenopathy and retroperitoneal fibrosis, respectively. Five conservatively followed-up patients were later given steroid therapy because of exacerbation of AIP involving the bile duct. Steroid therapy was effective in all patients. Pancreatic endocrine and exocrine dysfunctions and salivary gland dysfunction improved after steroid therapy in 100, 85, and 75% of patients, respectively. AIP relapsed in five patients initially treated with steroid, and presence of hilar bile duct stenosis and elevated serum IgG4 levels were significantly associated with relapse. Two relapsed AIP patients developed a pancreatic stone 2 and 3 years later. Although seven patients died, no patient died of AIP-related diseases or developed pancreatic carcinoma.

Most AIP patients treated with steroid had good short-term and long-term outcomes clinically, morphologically, and functionally. Hilar bile duct stenosis and elevated serum IgG4 levels were predictors of AIP relapse after steroid therapy. As some patients developed pancreatic stone formation or a malignancy during or after steroid therapy, AIP patients should be rigorously followed up.