Relationship among end-stage renal disease, hypertension, and sleep apnea in nondiabetic dialysis patients

Abstract

Cardiovascular diseases (CVD) are responsible for more than 50% of the deaths in patients with end-stage renal disease (ESRD). Sleep apnea (SA) has been recognized as a risk factor for CVD. Previous studies have shown a higher prevalence of SA among patients on dialysis. Forty-five nondiabetics patients with ESRD underwent a polysomnographic analysis with concomitant clinical evaluation and laboratory tests. Fourteen patients (31.1%) presented with an apnea/hypopnea index (AHI) more than 5, confirming a high prevalence of SA. We observed abnormal sleep pattern with high percentages of sleep stage 1 and low percentages of sleep stages 3 and 4. Patients with AHI more than 5 presented higher levels of systolic, diastolic, and mean blood pressures (MBP) as compared with those with AHI less than 5 (P < .05). When other variables were compared (age, time of dialytic treatment, cause of ESRD, use of antihypertensive drugs, body mass index, serum levels of hemoglobin, hematocrit, creatinine, KT/V index, pH, bicarbonate, parathormone, and alkaline phosphatase), no differences were found between the two groups. In a logistic regression model, MBP and age more than 40 years were positively related to the presence of SA. Our study is in agreement with previous works and shows that patients with ESRD have a higher SA index compared to those with normal renal function. In spite of having higher levels of BP no other parameter was different among apneic and nonapneic patients. Hypertension may play a pivotal role linking SA and CVD.