MON-302 The Prevalence of Acromegaly in the Sleep Apnoea Clinic

The prevalence of acromegaly in the general population ranges 4-14/100,000. 45-80% of acromegaly patients have obstructive sleep apnoea (OSA). The OSA population might represent a target group for earlier detection of acromegaly, thereby reducing associated long-term morbidity. Methods: Patients attending the sleep service (11/2014-04/2018) were recruited in a prospective multicentre cohort study. All had serum IGF-1 measurement and completed a screening questionnaire for five key symptoms associated with acromegaly. Those with raised age-specific IGF-1 underwent further biochemical assessment to investigate for acromegaly. Results: 1080 participants (73% male, mean age 55.6±12.0yrs) with confirmed OSA were recruited across two sites. Forty-three patients (4%) reported at least 4/5 acromegaly-related symptoms. There was no correlation between serum IGF-1 and symptom score. Sixty-one patients (5.7%) had elevated IGF-1 level on initial assessment. Fifty-one had repeat IGF-1 testing, while one had growth hormone measurement of <1µg/L. Nine patients were lost to follow-up, including one death. Of the repeat IGF-1 tests, results were normal in 24 cases and no further investigation was undertaken. Repeat IGF-1 results were unavailable in 3 cases. In the remaining 24 patients with persistently raised IGF-1, 11 had GH <1µg/L, suggesting that acromegaly was unlikely. The remainder (n=13), as well as the 3 individuals with unavailable IGF-1 results, had an oral glucose tolerance test. One patient (BMI of 23.7kg/m2) was diagnosed with acromegaly, was diagnosed with severe OSA and reported 4/5 acromegaly-related symptoms during screening. Conclusion: Our study identified a single case of acromegaly within the OSA population that may represent a higher prevalence than in the background population, however is based on a single case. As a consequence of the significant number of patients with elevated serum IGF-1 measurements requiring further investigation, IGF-I is not currently a cost-effective screening tool for early detection of acromegaly in OSA patients. Funding: Ipsen UK