Features and consequences of untreated type 1 autoimmune hepatitis

The existence of a mild form of autoimmune hepatitis that does not require treatment remains controversial. The aim of this study was to determine the existence, characteristics and outcome of this form. Untreated patients with type 1 autoimmune hepatitis who did not satisfy pre-established criteria for severe disease were identified retrospectively and compared with treated patients. Twenty-one of 282 patients (7%) who were evaluated during a 32-year period did not receive corticosteroid treatment. These asymptomatic patients constituted 15% of 137 patients who satisfied similar criteria for mild disease. Untreated patients with mild disease were indistinguishable from 116 treated patients with mild disease, and they differed from 145 treated patients with severe disease only by the pre-established features that defined disease severity. The eight untreated patients with follow-up assessments satisfied remission criteria less commonly than treated patients with mild or severe disease during 77 +/- 31 months of observation (12 vs 63%, P=0.006), and they had a lower 10-year survival (67 vs 98%, P=0.01). Four patients did improve spontaneously albeit short of remission criteria and remained well for 28 +/- 15 months (range, 5-73 months). Four patients worsened during 125 +/- 51 months of observation (range, 32-239 months), including two of three patients with cirrhosis who died of liver failure. Mild type 1 autoimmune hepatitis does exist, and it may be as frequent as severe disease. Untreated patients with mild disease can improve spontaneously, but there are no confident indices by which to identify this subgroup and justify withholding treatment.