The Use of the Low-Dose Short Synacthen Test in Assessing Hypothalamic-Pituitary-Adrenal Insufficiency in Post-Keratoplasty Patients on Ophthalmic Topical Corticosteroids

Abstract

Purpose: : Several studies have sought to identify if high dose inhaled corticosteroids cause suppression of the hypothalamic-pituitary-adrenal (HPA) axis, though no published research has studied patients receiving topical steroids for ocular pathologies since the 1970s. These studies only looked at short-term steroid use and in very few patients. To prevent graft rejection long-term low-dose topical corticosteroid is often necessary. The purpose of this study is to identify if there is a link between the prolonged use of topical ophthalmic corticosteroids preparations and adrenal suppression or insufficiency after corneal transplantation.

Methods: : Patients were recruited from the corneal transplantation service, in a tertiary eye hospital in the UK. They had been on daily topical steroids following penetrating keratoplasty, either prednisolone acetate 1% or 0.5% for longer than 6 months. There was no history of concomitant steroid use. All patients had measurements of serum cortisol followed by a low-dose standard Short Synacthen Test (LDSST), and then a normal dose Short Synacthen Test (SST). The widely accepted standard of HPA axis suppression/insufficiency defined as a base-line cortisol value of <190nmol/L, peak 30-minute LDSST cortisol of <550nmol/L or 30-minute SST cortisol of <550nmol/L.

Results: : The twenty patients consisted of 8 males and 13 females with a mean age of 71.6 (range 51 to 87) years and treatment duration of 55.9 (± 44.3) months. All patients were found to have adequate adrenal function based on the LDSST and SST with a mean base-line cortisol value of 458.9nmol/L (95%CI: 415.0 to 502.7), mean 30-minute LDSST cortisol 716.0nmol/L (95%CI: 671.7 to 760.3) and mean 30-minute SST cortisol 761.1nmol/L (95%CI:704.8 to 817.4).

Conclusions: : No patients have adrenal suppression according to the above definitions. Furthermore, none have adrenal insufficiency. This study clearly demonstrates the safe prophylactic use of long-term low dose topical steroids in corneal transplantation.

Keywords: corticosteroids • transplantation • cornea: clinical science