Sleep Apnea in Acromegaly

OBJECTIVE: To provide information on the nature, prevalence, and severity of sleep apnea in patients with acromegaly. DESIGN: Consecutive case series. SETTING: Tertiary referral hospital. PATIENTS: Fifty-three patients with acromegaly were consecutively referred: 33 patients were referred because of clinical suspicion of sleep apnea and 20 patients were referred without suspected apnea. MEASUREMENTS: Sleep studies as well as growth hormone and insulin-like growth factor 1 (IGF-1) measurements were done. MAIN RESULTS: Thirty-one patients (93%; 95% Cl, 85% to 100%) referred because of suspicion of sleep apnea had sleep apnea compared with 12 patients (60%; Cl, 37% to 83%) referred without suspected sleep apnea. Patients with sleep apnea did not have biochemical evidence of increased disease activity (random growth hormone, 12.7 +/- 4.4 micrograms/L; mean growth hormone at 24-hour sampling, 10.8 +/- 8.4 micrograms/L; IGF-1, 90.0 +/- 7.5 nmol/L) compared with patients without sleep apnea (random growth hormone, 14.2 +/- 4.9 micrograms/L, P greater than 0.2; mean growth hormone, 12.4 +/- 3.5 micrograms/L, P greater than 0.2; IGF-1, 90.0 +/- 10.0 nmol/L, P greater than 0.2). Central sleep apnea was the predominant type of apnea in 33% (Cl, 18% to 47%) of patients and was associated with higher random growth hormone and IGF-1 levels than was obstructive apnea (random growth hormone, 23.4 +/- 3.9 compared with 8.8 +/- 3.1 micrograms/L, P less than 0.001; IGF-1, 126 +/- 17.5 compared with 72.5 +/- 7.5 nmol/L, P less than 0.01). CONCLUSIONS: Sleep apnea is common in acromegaly. The rate of central sleep apnea was unexpectedly high in patients with acromegaly, and biochemical evidence of increased disease activity was associated with the presence of central apnea rather than with the degree of sleep apnea. Altered respiratory control is a possible mechanism producing sleep apnea in acromegaly.