Hypophysitis Outcome and Factors Predicting Responsiveness to Glucocorticoid Therapy: A Prospective and Double-Arm Study

Context Primary autoimmune hypophysitis (PAH) evolves in most untreated cases in irreversible hypopituitarism. PAH outcome, instead, after immunosuppressive treatment has not been completely clarified. Objective To evaluate hypophysitis and pituitary function outcomes. Design A prospective, double-arm study with a 2-year follow-up. Setting Referral center for pituitary disease. Patients Twenty PAH cases. Interventions Oral prednisone 50 mg/d or conservative strategy by observation. Main Outcome Measures Primary endpoint was the improvement/stabilization/worsening of PAH from baseline to a 2-year visit. Secondary endpoint was the improvement/stabilization/worsening of pituitary function from baseline to a 2-year visit. Results Twelve patients (57.1%) were treated with a glucocorticoid-immunosuppressive therapy, and eight patients (42.9%) were observed. At the 2-year visit, PAH improvement/recovery occurred in eight immunosuppressive-treated (66.7%) patients and in two untreated patients (25%). PAH worsened in three untreated patients (37.5%) and was considered stable in four immunosuppressive-treated (33.3%) and three untreated patients (37.5%). Improvement/recovery of pituitary function occurred more frequently in immunosuppressive-treated patients (58.3%) compared with untreated ones (25%; P = 0.04). Responsiveness to immunosuppressive treatment is correlated with antipituitary antibody presence (P = 0.01), occurrence of diabetes insipidus at PAH diagnosis (P = 0.01), absence of the physiological neuropituitary "bright spot" on T1-weighed images (P = 0.01), and pituitary stalk at optical chiasm larger than 3.9 mm (area under the curve: 0.97, sensibility: 100%, specificity: 100%; P = 0.04). On the other hand, we failed to identify factors predicting the outcome, among untreated patients. Conclusions Glucocorticoid treatment of hypophysitis improves pituitary secretion and should be encouraged in accordance with the evaluation of endocrine-, immunological-, and morphological-predictive markers.