Elevated incidence of sleep apnoea in acromegaly-correlation to disease activity

An elevated prevalence of sleep apnoea (SA) in patients with acromegaly has been suggested. We performed polysomnographies in 52 patients with acromegaly (25 m, 27 f, age 51 years, range 19-82 years). Patients were defined having SA if they had more than five apnoeas or hypopnoeas per hour (respiratory disturbance index = RDI). The type of SA was divided into obstructive (OSA), central (CSA) or mixed (OSA+CSA). Seventeen patients had newly diagnosed disease, and 18 patients were treated with somatostatin analogues. Twenty-three patients had controlled disease activity (mean GH levels < 1 mu g/l during a 3-h profile and normalised IGF-1 levels). Twelve had active acromegaly despite medical treatment. Thirty patients (58%) had SA. Twenty-five of those had OSA, three had CSA, and two had mixed. Of the patients with active disease, 66% had SA, compared to 48% in the cured group. Significantly more patients with hypertension (n = 18) than without hypertension (n = 12, p = 0.041) had SA. Basal glucose was not significantly different between patients with (100 mg/dl, range 75-207 mg/dl) and without SA (92 mg/dl, range 74-120 mg/dl), but HbA1c was significantly higher in patients with SA (5.9% (4.9-9.0%) vs. 5.4% (4.3-6.1%), p = 0.001). A positive correlation between RDI and BMI (p = 0.04), RDI and age (p = 0.013) and RDI and disease activity (p = 0.014) was seen. No major correlation could be found between RDI and the duration of disease activity nor between RDI and GH levels. RDI correlates positively with disease activity but not with the duration of the disease. The parameters of the metabolic syndrome are positively associated to the degree of SA in acromegalic patients.