Endocrine Abstracts

Background: Patients diagnosed with acromegaly have an increased prevalence of sleep apnea syndrome(SAS). The data are scarce regarding the effects of continuous positive airway pressure(CPAP) use on cardiovascular parameters in these patients. We aimed to prospectively evaluate the cardiovascular effects of CPAP in patients with SAS and acromegaly.

Methods: Adult patients with newly diagnosed acromegaly were performed metabolic (body mass index (BMI), glucose, lipid values) and cardiovascular evaluation studies (24-hour ambulatory blood pressure monitoring, 24-hour ambulatory electrocardiography, carotid intima media thickness(CIMT), echocardiography), and polysomnography at the time of diagnosis. Serum levels of HIF-1 alpha was measured. Quality of life was evaluated by AcroQoL questionnaire. Control group was matched in terms of age, gender and BMIs. Patients were randomly assigned to ‘CPAP-using’ and ‘no-CPAP’ groups, and prospectively evaluated one year after remission.

Results: Forty-nine patients(29 female), mean age 42.30±10.65 years, and 13 controls were included. Serum LDL, total cholesterol, and HIF-1 alpha levels were lower in the patient group (P=0.029, P=0.006, and P=0.021, respectively). Apnea-hypopnea index (AHI) was higher (P=0.004), and the results of cardiovascular evaluation studies were similar except for higher left ventricular posterior wall thickness at end-diastole among the patients (P=0.006). Average heart rate during polysomnography was higher in the patients (P=0.023). The patients were grouped on the basis of AHI scores (Group-1:AHI<5, Group-2:AHI ≥5 and <15, Group-3:AHI≥15). The mean age was significantly higher in Group-3 patients when compared to groups 1 and 2. AcroQoL was lower in Group-3. Glucose values, BMIs, echocardiographic parameters, CIMT, mean blood pressures(MAP), and heart rates, HIF-1 alpha levels were similar across the groups at baseline. ‘CPAP-using’ (n=8) and ‘no-CPAP’ (n=8) groups who achieved acromegaly remission were compared at first year. BMIs remained similar in both groups, but fat mass increased in non-users (P=0.018). AHI scores improved only among CPAP users (P=0.043). Left ventricular systolic(LVSD) and diastolic diameters(LVDD) were significantly lower in CPAP-users than non-users after one year. Minimum heart rate showed decrease only among CPAP-users (P=0.042). CIMTs, MAPs, serum HIF-1 alpha levels, and AcroQoL scores were similar at first year across the groups. HIF-1 alpha levels were positively correlated with LVSD and LVDD at baseline (P=0.008, r_s=0.476, P=0.005 r_s=0.499). AcroQoL score was negatively associated with AHI, and positively with average O2 saturations (P=0.012, r_s= -0.381, P=<0.001 r_s=0.611).

Conclusion: Use of CPAP in patients with OSAS and acromegaly after remission may lead to better outcomes in terms of cardiac structure and heart rate, but not QoL.