Repeated short corticotropin testing in patients with polymyalgia rheumatica.

Abstract

To investigate adrenal function and the prevalence of glucocorticoid (GC) induced adrenal insufficiency (GIAI) in patients with polymyalgia rheumatica (PMR), the first 18 months after diagnosis. Newly diagnosed patients with PMR underwent short corticotropin tests before commencement of GC treatment and after 10 weeks, 6 months, and 12 months. Patients still on GC or with GIAI after 12 months were invited to a test after 18 months. GIAI was defined as a stimulated serum cortisol level <420 nmol/l. : Sixty patients with PMR were enrolled. The mean (S.D.) stimulated cortisol levels declined significantly between baseline (678 ± 95) and month 6 (491 ± 114), followed by an increase at month 12 (549 ± 100). An inverse relationship was found between stimulated cortisol levels and current GC dose (P < 0.001). The proportion of GIAI peaked at month 6 (13/53, 25%) when all patients received GC. By 12 months, adrenal function had recovered in 12/13 (92%) of these patients. At month 12 and month 18, GIAI was present in 1/31 (3%) and 0/12 (0%), who were no longer receiving GC. Stimulated serum cortisol levels in patients with PMR did not reach pretreatment levels after cessation of GC treatment. GIAI was frequent but reversible during GC treatment for PMR, which supports the concept of increased GC dosing during stress in these patients. Implementation of routine use of the short corticotropin test for the diagnosis of GIAI after planned cessation of GC treatment in PMR is not justified by our data. Clinicaltrials.gov, http://clinicaltrials.gov, NCT04519580.