Repeated short corticotropin testing in patients with polymyalgia rheumatica

Area of Science:

• Endocrinology
• Rheumatology
• Pharmacology

Background:

• Polymyalgia rheumatica (PMR) is often treated with glucocorticoids (GCs).
• GC treatment can lead to adrenal insufficiency.
• The prevalence and reversibility of GC-induced adrenal insufficiency (GIAI) in PMR patients require further investigation.

Purpose of the Study:

• To investigate adrenal function in PMR patients.
• To determine the prevalence of GIAI during the first 18 months of GC treatment.
• To assess the reversibility of GIAI after GC cessation.

Main Methods:

• Newly diagnosed PMR patients underwent short corticotropin tests at multiple time points.
• Tests were performed before GC treatment, and at 10 weeks, 6 months, 12 months, and 18 months.
• GIAI was defined as a stimulated serum cortisol level below 420 nmol/l.

Main Results:

• Stimulated cortisol levels significantly declined by month 6 and showed an inverse relationship with GC dose.
• The prevalence of GIAI peaked at 25% at month 6, with most cases resolving by 12 months.
• Adrenal function did not consistently reach pre-treatment levels after GC cessation.

Conclusions:

• GIAI is frequent but reversible in PMR patients undergoing GC treatment.
• The findings support considering increased GC dosing during stress in PMR patients.
• Routine short corticotropin testing for GIAI diagnosis after planned GC cessation in PMR is not currently justified by the data.