MP433RELATIONSHIP OF OBSTRUCTIVE SLEEP APNEA WITH BODY ADIPOSITY AND INSULIN RESISTANCE IN NONDIALIZED CHRONIC KIDNEY DISEASE PATIENTS

Abstract

INTRODUCTION AND AIMS: Excessive adiposity is a risk factor for obstructive sleep apnea (OSA) and there is evidence that OSA is associated with insulin resistance independently of body adiposity. It is not known if these relationships observed in the general population also occur in chronic kidney disease (CKD) patients and probably they are different as some studies suggest that CKD favors the development of OSA. The presente study aimed to evaluate the association of OSA with total and central body adiposity and with insulin resistance in nondialized CKD patients. METHODS: Cross-sectional study, CKD patients (stages 3b-4), under regular treatment at an interdisciplinary outpatient clinic at a University Hospital. GFR was estimated by CKD-EPI equation. Patients were evaluated for: OSA, total and central body adiposity and glucose metabolism. Sleep study was performed with Watch-PAT200® . The diagnosis of OSA was made when apnea-hipopnea index (AHI) ≥5 events/h. Total body adiposity parameters were: body mass index (BMI) and body fat (dual-energy xray absorptiometry; DXA). Central body adiposity parameters were: neck circumference (NC), waist circumference (WC), waist-to-hip ratio (WHR), waist-to-height ratio (WHtR) and trunk fat (DXA). Glucose metabolism was evaluated by fasting plasma glucose, plasma insulin and insulin resistance (homeostasis model assessment of insulin resistance (HOMA-IR) index). Statistical analysis: STATA 12.0. P-value < 0.05 was considered statistically significant. RESULTS: 73 patients were studied (56% males, age= 62.7±8.9 years, eGFR= 29.0±8.9 mL/min). OSA was present in 67% (n=49). Patients with OSA compared with those without showed higher values for all total and central body adiposity parameters: BMI (23.6; 21.6-26.9 vs. 29.3; 25.0-31.3kg/m2, p=0.0001), body fat (20.6±7.4 vs. 27.2±7.6kg, p=0.001), NC (35.4±3.6 vs. 39.1±3.9cm, p=0.002), WC (83.0; 77.8-95.8 vs. 100.0; 95.5-106.0cm, p=0.0001), WHR (0.85±0.10 vs. 0.97±0.08, p=0.0001), WHtR (0.54±0.07 vs. 0.60±0.06, p=0.0001) and trunk fat (11.1±5.4 vs. 16.0 65.2kg, p=0.0005). Those with OSA also presented higher values for plasma glucose (91.0; 85.0-98.0 vs.102.5; 90.5-115.5mg/dL, p=0.03), insulin (7.1; 4.5-11.5 vs. 12.7; 7.4-18.3mcU/mL, p=0.008) and HOMA-IR (1.8; 1.0-3.4 vs. 3.0; 1.9-4.8, p=0.02). After exclusion of diabetic patients, glucose, insulin and HOMA-IR were significantly higher in OSA patients. However, after adjustment for BMI or total body fat, insulin and HOMA-IR were not significantly higher in OSA group. CONCLUSIONS: These data suggest that in nondialized CKD patients, OSA is associated with higher total and central body adiposity and with insulin resistance, but this latter association is not independent of adiposity.