Impact of kidney transplantation on sleep apnea severity: A prospective polysomnographic study.

Abstract

Fluid overload has been associated with a high prevalence of sleep apnea (SA) in patients with end-stage kidney disease (ESKD). In this prospective study, we hypothesized that improvement in kidney function and hydration status after kidney transplantation (Tx) may result in an improvement in SA severity. A total of 196 patients on the kidney Tx waiting list were screened for SA using home nocturnal polysomnography (PSG) to measure the apnea-hypopnea index (AHI) and underwent bioimpedance to assess body composition. Of 88 participants (44.9%) with SA (AHI≥15/h), 42 were reassessed 6months post-Tx and were compared with 27 control patients. There was a significant, but small, post-Tx improvement in AHI (from 44.2±24.3 to 34.7±20.9/h, P=.02) that significantly correlated with a reduction in fluid overload (from 1.8±2.0 to 1.2±1.2L, P=.02) and body water (from 54.9% to 51.6%, P=.003). A post-Tx increase in body fat mass (from 26% to 30%, P=.003) possibly blunted the beneficial impact of kidney Tx on SA. All parameters remained unchanged in the control group. In conclusion, SA is a frequent condition in ESKD patients and partially improved by kidney Tx. We suggest that SA should be systematically assessed before and after kidney Tx. ClinicalTrials.gov Identifier: NCT02020642.