Sleep Apnea is highly prevalent and may contribute to
insulin resistance in patients with
acromegaly. The primary aim of this study was to assess the impact of
sleep apnea treatment with a continuous positive air pressure (CPAP) device on
insulin resistance evaluated by hyperinsulinemic euglycemic clamp (HEC). A prospective, randomized, open label, placebo-controlled, crossover study was performed at a tertiary outpatient pituitary center. Twelve acromegalic subjects on
somatostatin analogs (SA) with a recent diagnosis of moderate to severe
sleep apnea were randomized to CPAP
therapy or to nasal dilator adhesive (NDA) with placebo effect for 3 months and then crossed over for another 3 months period without washout. Assessment of HEC, mathematical
insulin resistance indexes (HOMA, HOMA2 and QUICKI), GH,
IGF-1, HbA1c and free fat
acids were performed. A significant reduction on
insulin resistance was demonstrated by HEC at the end of the study in patients on CPAP (HEC, pre- and post-CPAP: 4.27 vs. 6.10 mg/Kg/min, P = 0.032). This reduction was not observed in NDA group (HEC, pre- and post-adhesive: 5.53 vs. 5.19 mg/Kg/min, P = 0.455). There was no significant difference on HbA1c or on peripheral
insulin resistance indexes in both treatments. CPAP promoted a significant increase on peripheral
insulin sensitivity in acromegalic patients with moderate to severe
sleep apnea on SA use. Our results support the concept that
sleep apnea plays an important role on
glucose metabolism.
Insulin resistance indexes were unable to detect this finding.