Prevalence of acromegaly among patients referred for sleep apnea syndrome: ACROSAS study

Introduction: Acromegaly has a prevalence about 0.01% in general population. SAS is experienced by up to 80% of those with acromegaly. The high frequency of acromegaly-related co-morbidities and late diagnosis make screening for acromegaly advisable in at risk populations such as SAS. Aims: To determine the prevalence of undiagnosed acromegaly in patients referred for SAS, using a standardized questionnaire and systematic measurement of serum insulin-like growth factor-1 (IGF-1). Methods: Patients referred for SAS to one University Hospital or to 10 participating private practices. Clinical data, co-morbidities and medications were recorded via the French Sleep Observatory. Included patients underwent polysomnography or respiratory polygraphy. When IGF-1 levels were elevated for age, a second measurement was made and combined with GH levels obtained during an Oral Glucose Tolerance Test. If necessary the patient underwent pituitary MRI and was examined by an endocrinologist for definite diagnosis of acromegaly. Results: Of 873 patients prospectively included, 817 had a measurement of serum IGF-I. 2 patients with acromegaly caused by pituitary adenoma were diagnosed and treated; both had severe SAS. The prevalence of acromegaly in our cohort was 0.25%. 567 patients had moderate to severe SAS with an apnea-hypopnea index>15; in this group the prevalence of acromegaly was 0.35% (27 fold the prevalence in the general population). Conclusion: The prevalence of acromegaly in patients with SAS is very high. Further studies are needed to evaluate the cost-effectiveness of systematic screening in patients presenting with SAS to diagnose acromegaly earlier and prevent complications and comorbidities.