PURPOSE: The prevalence of obstructive sleep apnea (OSA) varies between 16-54% in patients with chronic kidney disease. However its prevalence in renal transplant patients is less well studied. Furthermore, weight gain, a common side effect of post-transplant immunosuppression, is an important risk factor for OSA. We aimed to examine the prevalence of OSA and its clinical correlates in renal transplant patients referred for polysomnography (PSG) and to compare risk factors among patients with and without OSA.
METHODS: We performed a retrospective study of 35 renal transplant recipients who underwent PSG for sleep disturbances between 1989 and 2009. Demographic data, post-transplantation time to PSG, weight gain, immunosuppressant medicationss, and echocardiographic data were gathered. Sleep efficiency, sleep stages, apnea-hypopnea index (AHI), oxygen desaturation index (ODI), nadir oxygen saturations were recorded.
RESULTS: The group consisted of 17 women and 18 men. Subjects were middle-aged and obese (mean age 54+/-10.2 years and mean body mass index 37.6 +/-6.9). 24 of 35 (79.6%) patients had OSA with an AHI greater than 5 events per hour. One patient had central sleep apnea. Subjects had moderate OSA (AHI 25.9 and ODI 16.85) ) and reduced sleep efficiency (79%+/-17.4). An increase in N1 sleep (mean 19.3% of total sleep time) and a decrease in rapid eye movement sleep (mean 10% of total sleep time) were observed. The mean nadir oxygen saturation was 78.5% +/-13.1 indicating hypoxemia. Subjects with OSA had more post-transplantation weight gain (11.89 kg vs. 9.75 kg) but this was not significant. Use of prednisone did not differ between groups (75% vs 80%) and was not associated with the presence of OSA (p=0.75).
CONCLUSIONS: The incidence of OSA in renal transplant recipients is very high. Weight gain is common following transplantation; however, use of prednisone post-transplantation was not associated with OSA.
CLINICAL IMPLICATIONS: Clinicians should be mindful of OSA in renal transplant patients. OSA should be screened as a part of routine care in this population.
DISCLOSURE: The following authors have nothing to disclose: Marcia Henderson, Shirley Jones
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