Cognitive function in patients with primary adrenal insufficiency (Addison's disease)

Abstract

Background: Patients with primary adrenal insufficiency (AI) need to replace glucocorticoids and mineralocorticoids that act on glucocorticoid (GR) and mineralocorticoid receptors (MR). Both receptors are highly expressed in the hippocampus and are closely associated with cognitive function, which might be impaired by insufficient or increased GR and MR stimulation. However, little is known about cognitive function in patients with AI.

Methods: It was examined whether patients with AI exhibit worse cognitive function compared to sex-, age-, and education-matched controls. Cognitive function (executive function, concentration, verbal memory, visual memory, working memory, and autobiographical memory) was assessed in 30 patients with AI (mean age 52.4 yrs. ±14.4, n=21 women, mean duration of illness 18.2 yrs. ±11.1) and 30 matched controls. We also measured depressive symptoms, body mass index (BMI), and blood pressure.

Results: Patients with AI showed more depressive symptoms, had a greater BMI and lower systolic blood pressure compared to controls. Adjusted analyses controlling for these variables revealed that patients with AI performed significantly worse in verbal learning (F=7.8, p=.007). Executive function, concentration, working memory, verbal memory, visuospatial memory, and autobiographical memory did not differ between groups.

Conclusions: No clinically relevant cognitive impairment was found in patients with AI compared to matched controls. Even long-term glucocorticoid and mineralocorticoid substitution over almost two decades appears to have only subtle effects on cognition in patients with AI.

Keywords: Addison's disease; Cognition; Cortisol; Fludrocortisone; Mineralocorticoid and glucocorticoid receptor; Primary adrenal insufficiency.