Stage 1 (increased plasma renin) for patients with APS-1 and Stage 2 (no response of cortisol to ACTH-test) for patients with APS-2/APS-4 were established as the points of no return in the progression to AAD.
The natural history of AAD usually comprises five consecutive stages with the first stage characterized by the increase of plasma renin consistent with the impairment of pars glomerulosa, which is usually the first affected layer of the adrenal cortex.