ABSTRACT
OBJECTIVE: Patients with rheumatic diseases are often treated with prolonged, high-dose systemic glucocorticoids which can cause hypothalamic-pituitary-adrenal (HPA) axis suppression and development of tertiary adrenal insufficiency. Adrenal insufficiency carries the risk of serious, potentially life-threatening adrenal crisis. Our study evaluated the prevalence, characteristics and recovery of patients with underlying rheumatology conditions who had received prolonged glucocorticoid treatment. DESIGN AND PATIENTS: Retrospective, cross-sectional study. We evaluated 238 patients seen in outpatient rheumatology clinic, managed in accordance with current nationally and internationally accepted clinical guidelines. MEASUREMENTS: Data collected included patient demographics, historical steroid data, 09.00 h cortisol/short synacthen test (SST) results and follow-up data on those with repeat assessments. RESULTS: Overall, 65% of our cohort had a 09.00 h cortisol <350 nmol/L. On SST, 43% of patients demonstrated evidence of possible tertiary adrenal insufficiency. Prednisolone equivalent dose at time of SST was significantly higher in the group who failed SST vs. those who passed; mean of 5.57 mg vs. 3.59mg (p = .005). 09.00 h cortisol result correlated with 30-min cortisol on SST (R2 = .20, p = .002). 0-min cortisol on SST correlated more strongly with 30-min cortisol than 09.00 h cortisol (R2 = .59, p-value < .001). Patients with 0-min cortisol >350 nmol/L, all passed their SST. Patients who remained on prednisolone were more likely to recover (71%) vs. those switched to hydrocortisone (27%), P = .02. Peak steroid dose was predictive of recovery; significantly lower in those who recovered (mean of 22.3 mg vs. 33.8 mg, P = .03). Steroid duration was not found to be a predictor of recovery [recovery (64.2 months) vs. non-recovery (55.6 months), P = .58]. There was no correlation found to outcome on SST with age, sex, peak steroid dose, steroid duration, underlying rheumatological condition, additional exogenous steroid use or serum sodium. CONCLUSIONS: Forty three percent of our patients demonstrated sub-optimal adrenal function on SST. Steroid dose at the time of SST was the only significant predictive risk factor for tertiary adrenal insufficiency. 09.00 h cortisol demonstrated good correlation with outcome on SST and could represent a valid screening test to reduce need for SST if 09.00 h >350 nmol/L. Further prospective data are required to further characterize risk factors, predictive features of recovery and establish optimal management strategy of steroids (prednisolone vs hydrocortisone) to encourage adrenal recovery.
