Introduction: Cushing’s disease (CD) is associated with high mortality rate especially with persistent disease. [1, 2] Our aim was to identify predictors of remission using our long-term follow-up data on CD patients.
Method: All histories of patients with treated CD at RMH and RAH between 1990-2016 were reviewed. A binary regression model was used for statistical analysis.
Results: Eighty-seven patients had long term clinical outcome available. Mean follow-up period was 9 years (IQR 2.7-14.4). Thirty patients (34%) were male and mean age of diagnosis was 45 years (IQR 35-57). Macro-adenoma were more common in males (50% vs 21%). Osteoporosis rate was highest (50%) in males with low testosterone level (< 6nmol/L). Median weight loss was 10kg at 1 year follow-up (IQR 4-12) but this wasn't sustained in the long-term. After repeated operations, a higher rate of diabetes insipidus (41% vs 24%, p value=0.04) and CSF leak (11% vs 4%, p value=0.04) were seen but not SIADH (6%). Mortality in the cohort was low (6%). Remission was achieved in 43 patients (49%) after first surgery and the rate was higher (60%) for surgeries performed between 2007-2016, although mean follow-up time was shorter: 6.1 years (IQR 1.9-8.7) vs 3.4 years (IQR 1.2-6.3). Overall, factors associated with achieving clinical remission post initial surgery included: micro-adenoma (OR 8.41, p value=0.03), age > 35 years (OR 4.36, p value=0.01) and initial surgery performed between 2007-2016 (OR 4.9, p value=0.001). Identification of micro-adenoma on initial MRI (p value=0.31) and level of 24 hour urinary free cortisol (p value = 0.28) weren't found to be associated with clinical outcome.
Conclusion: In our study, higher rates of DI and CSF leak were seen with repeated pituitary operations. Factors associated with remission post initial surgery in long term follow-up include micro-adenoma, age >35 years and operation performed between 2007-2016.