Reversible central adrenal insufficiency in survivors of COVID-19: results from a 24-month longitudinal study.

Objective: We studied the temporal course of hypothalamic-pituitary-adrenal (HPA) dysfunction in patients with coronavirus disease 2019 (COVID-19).

Methods: Three hundred and two patients (median age 54 years (interquartile range (IQR) 42-64), 76% males) were recruited. The HPA axis was evaluated by morning cortisol and adrenocorticotrophic hormone (ACTH) at admission (n = 232). Adrenal insufficiency (AI) during acute illness was defined using a morning cortisol <83 nmol/L. AI at 12 months follow-up was defined using a peak cortisol <406 nmol/L in the ACTH stimulation test (APST) (n = 90). Those with AI at 12 months were further assessed by APST every 6 months for recovery of hypoadrenalism.

Results: The median morning cortisol and ACTH levels during COVID-19 were 295 (IQR 133-460) nmol/L and 3.9 (0.8-6.9) pmol/L, respectively. AI was present in 33 (14%) patients; ACTH was elevated in three and low or inappropriately normal in the rest 30 patients. At 12 months, AI was seen in 13% (12/90) patients, with all cases being hypothalamic-pituitary in origin; five (42%) of them had not met the diagnostic criteria for AI during COVID-19. AI diagnosed at admission persisted at 12 months in seven patients and recovered in seven; the remaining 19 patients were lost to follow-up. The presence of AI at 12 months was independent of severity and steroid use during COVID-19. A morning cortisol <138 nmol/L during COVID-19 predicted the presence of AI at 12 months. All patients showed recovery of the HPA axis in the ensuing 12 months.

Conclusion: Central AI was common during acute COVID-19 and at 12 months of follow-up. AI can be late onset, developing after recovery from COVID-19, and was transient in nature.