Long-Term Changes in Sleep Disordered Breathing in Renal Transplant Patients: Relevance of the BMI

Francesca Mallamaci; Rocco Tripepi; Graziella D'Arrigo; Gaetana Porto; Maria Carmela Versace; Carmela Marino; Maria Cristina Sanguedolce; Giovanni Tripepi; Carmine Zoccali

doi:10.3390/jcm9061739

Long-Term Changes in Sleep Disordered Breathing in Renal Transplant Patients: Relevance of the BMI

J Clin Med. 2020 Jun 4;9(6):1739. doi: 10.3390/jcm9061739.

Authors

Francesca Mallamaci^{1

2}, Rocco Tripepi¹, Graziella D'Arrigo¹, Gaetana Porto¹, Maria Carmela Versace¹, Carmela Marino¹, Maria Cristina Sanguedolce¹, Giovanni Tripepi¹, Carmine Zoccali¹

Affiliations

¹ CNR-IFC Clinical Epidemiology of Renal Diseases and Hypertension Unit, Center of Clinical Physiology, National Research Council of Italy, Reggio Cal., c/o Ospedali Riuniti, 89124 Reggio Calabaria, Italy.
² Department of Medicine, Division of Nephrology and Transplantation, Ospedali Riuniti, 89124 Reggio Calabria, Italy.

Abstract

Sleep disordered breathing (SDB), as defined by the Apnea Hypopnea Index (AHI), is a highly prevalent disturbance in end stage kidney disease. SDB improves early on after renal transplantation but long-term changes in AHI in these patients have not been studied. We studied the long-term changes in AHI in a series of 221 renal transplant patients (mean age: 47 ± 12 years; 70% males) over a median follow up of 35 months. Data analysis was made by the generalized estimating equations method (GEE). On longitudinal observation, the median AHI rose from 1.8 (Interquartile range: 0.6-5.0) to 2.9 (IQR: 1.0-6.6) and to 3.6 (IQR: 1.7-10.4) at the second and third visit, respectively (p = 0.009 by the GEE model and the proportion of patients with moderate to severe SDB rose from 8% to 20%. Longitudinal changes in minimum oxygen saturation (minSaO₂) mirrored those in the AHI. In adjusted analyses, repeated measurements of BMI (p < 0.009) emerged as the strongest independent longitudinal correlate of AHI and MinSaO₂. The AHI worsens over time in renal transplant patients and longitudinal changes of this biomarker are directly related to simultaneous changes in BMI. Overweight/obesity, a potentially modifiable risk factor, is an important factor underlying the risk of SDB in this population.

Keywords: Body Mass Index (BMI); Chronic Kidney Disease (CKD); cardiovascular risk; renal transplantation; sleep apnea.