Sleep apnea in kidney transplant patients: Clinical correlates and comparison with pretransplant patients

BackgroundSleep disordered breathing (SDB) is a prevalent, but forgotten, cardiovascular (CV) risk factor in end-stage renal disease patients. Studies of SDB in renal transplant patients are few with mixed results.ObjectivesTo assess the prevalence and clinical correlates of SA in patients who received a kidney transplant, and to compare the prevalence of SA between waiting list and transplant patients.Subjects and methodsOur study included 40 clinically stable renal transplant patients and 15 patients awaiting transplantation. Patients with morbid obesity, diabetes, pulmonary disease or symptomatic heart failure were excluded from the study. All patients underwent overnight polysomnography, demographic and clinical data were also collected.ResultsWe found that the prevalence of SA was high in both the transplant and the waiting list groups (38% vs 47%). The severity of SA didn’t show significant difference in both groups (AHI = 9.6 vs 16.2). Moreover, we found a significant association between impaired renal function and the AHI in Tx patients. Also, SA was associated with difficult-to-treat hypertension in Tx patients as we found a significant association between the AHI and the systolic blood pressure as well as the number of prescribed antihypertensive drugs.ConclusionSA is as highly prevalent in Tx as in WL patients. Moreover, this high prevalence in the transplant patients could be a consequence of declining renal function. In addition, we propose that sleep apnea is a new risk factor for hypertension and cardiovascular events in kidney-transplanted patients.