Endocrine Abstracts

Background: The hypothalamic-pituitary-adrenal (HPA) axis can be suppressed by long-term exogenous glucocorticoids, resulting in tertiary adrenal insufficiency (AI). International expert consensus suggests that during weaning, prednisolone be converted to hydrocortisone to allow HPA axis reactivation⁽¹⁾. There is, however, little evidence to support this practice.

Aim: To compare HPA axis recovery during treatment with prednisolone and immediate-release hydrocortisone.

Methods: This is a retrospective study of patients diagnosed with tertiary AI (failed short synacthen test [SST]) attending a dedicated adult endocrine steroid clinic between 2015-2022. Patients were either weaned down to a physiological replacement dose of prednisolone or had been converted to immediate-release hydrocortisone. Patients were followed up with repeat SST to confirm HPA axis recovery demonstrated by a subsequent normal SST.

Results: 276 patients had SST of which 161 had an abnormal result. After excluding patients with no subsequent SST or taking different or multiple steroids, a total of 119 patients were included in final analysis: 41 on prednisolone and 78 on hydrocortisone (48 previously on hydrocortisone; 30 converted during study period). The rate of HPA axis recovery in prednisolone group was 61% (n=25), compared to 24% (n=19) in hydrocortisone group (P<0.001). There was no mean difference in age (60 v 55 years; −4.3 years, 95%CI −10.5, 1.9), sex (females 63% v 59%; P=0.64), baseline cortisol at 1^st SST (144 v 124 nmol/l; -19.7 nmol/l 95%CI -56.5, 17.0), baseline ACTH (22 v 30 ng/ml; 7.4 ng/ml 95%CI-3.0, 18.3), or duration of underlying diagnosis (4353 v 5360 days; 1133 days 95%CI -747, 3014) between the two groups. Mean follow up duration in prednisolone group was significantly lower (354 v 579 days; 225 days 95%CI 98.6, 350.8). Recovery rate in patients (n=30) in prednisolone to hydrocortisone switch subgroup also had similar recovery rate (27%) to overall hydrocortisone group.

Conclusion: This is the first study to compare HPA axis recovery during treatment with prednisolone and hydrocortisone. HPA axis recovery was more common in the prednisolone-treated patients and recovery time shorter compared to those on hydrocortisone. Prospective randomised studies with standardised treatment regimens are required to confirm our findings as selection bias may have influenced the conversion to immediate-release hydrocortisone in patients predicted to have slower recovery of the HPA axis.

Reference: Suehs et al. Oral Corticosteroids Tapering Delphi Expert Panel. Expert Consensus on the Tapering of Oral Corticosteroids for the Treatment of Asthma. A Delphi Study. Am J Respir Crit Care Med. 2021 Apr 1;203(7):871-881