Prevalence of sleep apnea and lung function abnormalities in patients with acromegaly

Abstract

Background: Sleep apnea (SA) is highly prevalent in acromegaly. Ethnicity influences the prevalence of SA in the general population. We studied the prevalence of SA and other respiratory comorbidities in North Indian patients with active acromegaly. Design: Prospective, observational. Materials and Methods: Consecutive adult patients with active acromegaly (n = 35, age 39.7 ± 13.2 years) and hypersomatotropism (nonsuppression of serum growth hormone after oral glucose and elevated serum insulin-like growth factor-1 [IGF-1]) were evaluated for respiratory symptoms, scoring for SA (Epworth Sleepiness Score [ESS] and STOP-BANG), pulmonary function tests (PFT), high-resolution computerized tomography (HRCT) of the thorax, polysomnography (PSG), and transthoracic echocardiography. Age-and sex-matched healthy individuals (n = 34) served as controls. Results: Acromegaly subjects had dyspnea (34%), cough (37%), excessive daytime somnolence (43%), and fatigue (49%). Clinically significant ESS (>10) and STOP-BANG score (≥3) were present in 41% and 68.6% of subjects, respectively. PFT showed restrictive and obstructive patterns in 45.7% and 11.4% of acromegalics respectively; with higher total lung capacity (TLC), thoracic gas volume (TGV), and residual volume (RV). PSG revealed significantly higher SA events in acromegalics (central [acromegaly 24.63 ± 37.82 vs. control 3.21 ± 5.5], mixed [11 ± 19.46 vs. 3.50 ± 5.96], obstructive [34.86 ± 44.37 vs. 9.71 ± 10.48], and mean apnea-hypopnea index [AHI] [16.91 ± 18.0 vs. 7.86 ± 7.84]). Acromegalics had significantly higher prevalence of obstructive SA (71.4% [mild 31.4%, moderate 20%, severe 20%]) as compared to controls (38.2%). There was no correlation of AHI with serum IGF-1 and disease duration. Conclusion: Acromegaly subjects have a significantly higher prevalence of respiratory symptoms, SA, and abnormalities in PFT. Screening for respiratory comorbidities should be routinely recommended in all patients with acromegaly.