Effect of transsphenoidal surgery on sleep apnoea in acromegaly

Sleep apnoea syndrome (SAS) is common in acromegaly and both diseases are independently associated with hypertension and insulin resistance contributing to increased morbidity and mortality. Pituitary surgery remains the principal treatment modality in acromegaly. The aim of this study was to assess the prevalence and risk factors of SAS in acromegaly and to analyze the effect of transsphenoidal adenomectomy on SAS and cardiovascular risk factors.

Thirteen consecutive patients (seven women and six men, aged 25-77 years) with newly diagnosed acromegaly were prospectively studied. Biochemical assessment (IGF-I, GH, acid labile subunit, fasting blood glucose (FBG), insulin), overnight respiratory polygraphy, and an Epworth Sleepiness scale score (ESS) were obtained before and 12 weeks after surgery. SAS was defined by an ESS > or = 10 and > or = 5 apnoeas/hypopnoeas (central or obstructive) per hour.

Six of the thirteen (46%) patients had SAS. Risk factors were male gender (83.3 vs 14.3% without SAS) and long disease duration until diagnosis of acromegaly (10.2 +/- 3.2 vs 4.6 +/- 3.6 years, mean +/- S.D.). Ten patients had a homeostasis assessment model score > or = 4 indicating insulin resistance and one had diabetes mellitus requiring insulin. Seven patients had hypertension (> or = 140/90 mmHg). Postoperatively, GH and IGF-I levels decreased, but only five patients were cured. However, SAS resolved in all patients irrespective of whether acromegaly was cured or not. FBG (5.5 +/- 1.2 vs 4.8 +/- 0.4 mmol/l) and systolic blood pressure (150.8 +/- 18.5 vs 130.8 +/- 17.5 mmHg) decreased in all SAS patients.

We found a high prevalence of SAS in acromegaly patients, in particular, in men and those with long duration of disease. Importantly, a marked reduction of GH excess by transsphenoidal adenomectomy may cure SAS and improve insulin resistance and hypertension.