Effect of CPAP in the Worsening of Renal Function in Early Stages of Chronic Kidney Disease (CKD)

Effect of CPAP in the Worsening of Renal Function in Early Stages of Chronic Kidney Disease (CKD)

Objectives: Evaluate the effect of CPAP to reduce the progression of chronic kidney disease or CKD (the decline of glomerular filtration rate is ≥ 30%) in patients with early-stage renal disease and sleep apnea syndrome (OSAS). Other objectives are; determine the prevalence of OSAS in patients with early-stage renal disease and evaluate the changes in inflamatories markers and endothelial damage, the state of KDIGO, cardiovascular events, mortality and cost-effectiveness analysis in CPAP group versus non-CPAP group patients.

Methods: A prospective, multicentric, randomized and controlled study will be carried out for 3 years. Early-stage renal disease (G1-3 KDIGO) and OSAS patients will be included. The investigators will make a respiratory polygraphy to determinate OSAS (AHI ≥15/h) and after that, the investigators randomized patients in 2 groups; CPAP group and control group (non-CPAP treatment). Patients with AHI <15/h (non-OSAS) will be the reference group and the half of these patients, randomly chosen, will be followed up at the end of the follow up.

Statistic analysis: the investigators will analyze the differences in glomerular filtration rate before and after the treatment, comparing the percentage of patients with CKD progression for both groups. The investigators will use the chi square test with raw data and adjusted for confounding variables using intention to treat analysis with imputation of missing values.

There is a bidirectional involvement between the chronic kidney disease (CKD) and sleep apnea syndrome (OSAS). The declining of renal function, the fluid overloading and the disturbance of ventilation control could cause sleep apneas. On the other hand, the nocturnal hypoxia in patients with OSAS has been associated with changes in the renin-angiotensin system and sympathetic nervous system and production of reactive oxygen species. These findings are relationed with the deterioration of kidney function.

Inclusion Criteria:

• Patients referred to the outpatient nephrology department with a diagnosis of chronic kidney disease stages G1-3 KDIGO
• Older than18 years
• Habitual snoring or observed apneas
• Scale sleep sleepiness (Epworth Test) with 11 points or lower.

Exclusion Criteria:

• Very debilitating chronic or neoplastic disease
• Respiratory failure (PaO 2 <55 mm Hg).
• Other symptoms of suspected sleep disorder different from OSAS.
• Patients unable to perform self-administered questionnaires.
• Patients with> 50% of central apnea or Cheyne-Stokes.
• Patients who do not sign the informed consent.