Obstructive sleep apnea in cushing's syndrome

Cushing's syndrome is a rare endocrine illness. Although its reported  incidence is about 10 cases per million people each year, it is estimated to be much higher in subclinical scenarios. It can lead to several pathologies such as diabetes, hypertension, high triglycerides, blood clots, osteoporosis, muscle loss and cardiovascular mortality.

The current study adds obstructive sleep apnea as another possible complication of CS, independent of age, gender, body mass index and insulin resistance.

Should patients with obstructive sleep apnea be screened for subclinical cushing’s syndrome?





December 2016

Objective: Diabetes mellitus and obesity are well-known risk factors associated with obstructive sleep apnea (OSA). Cushing's syndrome (CS) is also characterized by obesity and diabetes mellitus. However, the association between CS and OSA remains unclear. Therefore, we investigated the possible associations between CS and OSA in this study.

Patients and Methods: 30 female patients with newly diagnosed active CS and 30 age - , gender and body mass index (BMI) - matched female controls were included in this study. All of the participants were evaluated by an overnight polysomnography. OSA was defined as having anapnea-hypopnea index (AHI) score of ≥5 events/hour. BMI was recorded and iInsulin resistance was calculated by homeostasis model assessment (HOMA) scores. Fasting serum cortisol was also determined.


The mean HOMA (P=0.046) and AHI (P=0.028) scores were higher in patients with cushing's syndrome compared to the control subjects. AHI was positively correlated with the HOMA scores (r=0.281, P=0.046) in both groups.

Linear regression analysis showed that serum cortisol remained as an independent predictor for AHI after controlling for BMI and HOMA score (P<0.001).

Frequency of OSA was higher (50% vs. 23%, P=0.003) in patients with cushing's syndrome compared to the control subjects.


The risk of OSA increased in patients with cushing's syndrome compared to control subjects with similar ages and BMI levels.

Hypercortisolemia is an independent risk factor for developing OSA.

The presence of OSA needs to be considered in patients with CS.