Mortality is two to three times higher in patients with adrenal incidentalomas who have autonomous cortisol secretion levels of 83 nmol/L (3 µg/dL) or more after a 1 mg dexamethasone suppression test (DST), compared with those with levels below this, new research finds.
Autonomous cortisol secretion (ACS) has been linked to hypertension, cardiovascular disease, type 2 diabetes, and early mortality, and risks vary by cortisol level.
“To adequately decide whether treatment should be surgery or medical management of possible complications, it is essential to know the risk associated with the actual level of ACS,” write Albin Kjellbom, MD, of Skåne University Hospital, Lund, Sweden, and colleagues, in their article published May 25 in Annals of Internal Medicine.
Asked to comment, Salila Kurra, MD, of the Columbia adrenal center, Columbia University, New York, told this news organization that “this idea that mild cortisol excess that doesn’t meet the threshold for overt Cushing’s can, in and of itself, cause increased morbidity and mortality is something people have been thinking about for many years now.”
“But there isn’t very clear guidance on exactly what to do in that situation, whether the incidentaloma should be removed, medically managed, or the patient should just be watched ... It may be clinically significant, but the way to sort that out is to do other testing.”
Most deaths were from cardiovascular disease or cancer
Adrenal lesions are found incidentally in approximately 2% to 7% of the adult population who undergo abdominal imaging, and up to a third of those have ACS in the absence of clinical signs of Cushing syndrome.
European guidelines state that a plasma cortisol level of 138 nmol/L (5 µg/dL) or greater following DST defines ACS, and a level less than 50 nmol/L (1.8 µg/dL) rules it out, while values 50-137 (1.8-5 µg/dL) are deemed “possible” ACS.
For their study, the authors retrospectively analyzed 1,048 consecutive patients with adrenal incidentalomas seen at two Swedish hospitals between 2005 and September 2015 who were followed for up to 14 years.
The patients were a median age of 64.9 years, and 58.5% were women.
At baseline, 45.1% had a cortisol level of 50 nmol/L (1.8 µg/dL) or higher following DST, 52.9% had hypertension, 18.7% had diabetes, and 20.6% had a medical history of one or more cardiovascular events. A total of 54 patients underwent adrenalectomy, eight of them more than 2 years after the DST.
Researchers found a linear increase in mortality risk with increasing cortisol values up to 200 nmol/L (7.25 µg/dL) following DST.
Over 14 years, 16.2% (170 patients) died. Compared with cortisol less than 50 nmol/L (1.8 µg/dL) following DST, adjusted hazard ratios for mortality were 2.30 and 3.04 for cortisol levels 83 to 137 nmol/L (3-5 µg/dL) and 138 nmol/L (5 µg/dL) or greater, respectively, and both were significant.
Among the patients who died, causes of death were cardiovascular disease in 38%, cancer in 30%, infection in 4%, and other diseases in 28%.
Patients with post-DST cortisol levels of 83 nmol/L (3 µg/dL) or higher had increased cardiovascular mortality, while those with levels of 50-82 nmol/L (1.8-3.0 µg/dL) did not. In contrast, mortality rates from cancer, infection, and other diseases didn’t vary across groups.