Prevalence of cortisol deficiency in late HIV disease

In order to determine the prevalence of cortisol deficiency in advanced HIV disease and to examine whether it may be predicted by clinical features or biochemical abnormalities, we conducted a prospective study which assessed responses to a rapid ACTH stimulation test (short-duration synthetic corticotrophin test, synacthen test) in HIV-positive patients with a CD4 count of < or = 50 x 10(6)/l. Subjective fatigue, postural drop in blood pressure, electrolyte changes, presence of concurrent opportunist infection and drug treatment were recorded. Cortisol responses were defined as 'normal' (a post stimulation cortisol level > or = 450 nmol/l), 'abnormal' (post stimulation cortisol level < 350 nmol/l) or 'impaired' (an intermediate response). Of 49 patients tested (42 male, seven female), a suboptimal response (abnormal or impaired) was found in 14 (29%) and frank insufficiency in eight (16%). Cortisol deficiency was not predicted by postural drop in blood pressure, biochemistry or symptoms of fatigue. Patients with an impaired/abnormal test were not more likely to have cytomegalovirus or mycobacterial disease but were more likely to be taking megestrol acetate (P = 0.05, Fisher's exact test). Two of three patients with initially normal tests developed impaired/abnormal cortisol responses on re-testing 6-9 months later. Cortisol deficiency is common in late stage HIV disease, but symptoms of fatigue and postural hypotension, as well as biochemical findings, are poor predictors of cortisol deficiency. We found good subjective response to therapy. Routine screening by a rapid ACTH stimulation test is recommended in HIV-positive patients with CD4 count < or = 50 x 10(6)/l. Re-testing at regular intervals may be necessary. The interaction between megestrol acetate, cortisol metabolism and synacthen testing requires further investigation.