Effect of CPAP therapy on kidney function in patients with obstructive sleep apnoea and chronic kidney disease: a protocol for a randomised controlled clinical trial

Abstract

IntroductionObstructive sleep apnoea (OSA) is common in patients with chronic kidney disease (CKD) and may contribute to the progression of kidney disease either through direct effects of hypoxia on the kidney or indirectly through hypoxaemia-induced oxidative stress, endothelial dysfunction, inflammation, activation of the renin–angiotensin and sympathetic nervous systems, and hypertension. Treatment of OSA with continuous positive airway pressure (CPAP) improves many of these physiological abnormalities in patients with normal renal function, though to date there are no trials evaluating the effect of OSA treatment on kidney function in patients with CKD. The purpose of this study is to test the feasibility and efficacy of CPAP therapy in CKD patients with OSA.Methods and analysisThe study is a randomised, controlled, non-blinded, parallel clinical trial in which patients with established CKD are screened for OSA. Patients with OSA are randomised to either conventional medical therapy (control group) or medical therapy and CPAP (CPAP group) and followed for 1 year. The primary outcome is the change in estimated glomerular filtration rate. Secondary outcomes are the change in the urinary albumin/creatinine ratio, the Epworth Sleepiness Scale , Pittsburgh Sleep Quality Index and Kidney Disease Quality of Life questionnaire.Ethics and disseminationEthics approval has been obtained from the Conjoint Health Research Ethics Board (ID: REB15-0055). Results from this study will be disseminated through presentations at scientific conferences and publication in peer-reviewed journals.Trial registration numberNCT02420184; Pre-results.

Effect of CPAP Therapy on Kidney Function in Patients With Chronic Kidney Disease

“…This 12-month longitudinal study was a randomized, nonblinded, parallel clinical trial. A detailed description of the protocol has been published 32 and is summarized in Figure 1. Briefly, patients who met age and eGFR criteria and provided informed consent underwent a home sleep apnea test (HSAT) to determine if they had OSA and nocturnal hypoxemia.…”

“…To date, no randomized controlled trials have investigated the effect of CPAP on renal outcomes in patients with CKD. Accordingly, we performed a pilot study to investigate the effect of CPAP therapy on the estimated glomerular filtration rate (eGFR) and urine albumin to creatinine ratio (ACR) 32 in patients with established CKD who had coexisting OSA. We hypothesized that CPAP would slow the decline of eGFR and reduce albuminuria in patients with stages 3 and 4 CKD (eGFR, 15-60 mL/min/1.73 m 2 ) compared with those who did not receive CPAP.…”

Continuous Positive Airway Pressure Improves Renal Function in Obese Patients With Obstructive Sleep Apnea Syndrome

“…On the other hand, in the last few years, some Authors focused their attention on the prevalence of OSAS in the first stages of renal dysfunction, even if the majority of the studies is based on patients' history collection and not on sleep instrumental study ( 36 ). It is well-known that obesity, a risk factor of OSAS, is associated with glomerular hyperfiltration but, on the contrary, very little is known about the impact of breathing sleep disorders on renal hemodynamic in these subjects ( 20 , 21 , 37 – 39 ).…”

“…Previous studies investigating the effect of CPAP treatment on renal function were conducted in patients with CKD ( 20 ) or in non-obese OSAS patients with normal renal function ( 21 ) but, to our knowledge, no data exist in obese OSAS subjects with normal renal function. Thus, we designed this study to evaluate the effect of CPAP therapy on renal function in a cohort of well-characterized obese patients with moderate-to-severe OSAS and preserved renal function (e-GFR > 60 ml/min/1.73 m 2 ).…”

Chronic kidney disease in patients with obstructive sleep apnea. A narrative review

“…Two small studies [101,102] Only one randomised controlled study has been published so far on long-term effects of CPAP on kidney function, which was a sub-study of the SAVE trial [106] on 200 patients without severe nocturnal hypoxemia followed up for a median period of In summary, despite a few studies support that treatment of OSA by CPAP has beneficial effects on the kidneys, some controversy still exists, and further stronger evidence is required to better clarify this issue. Large randomized trials are urgently needed and one has already been planned [111].…”