Effects of Nasal Continuous Positive Airway Pressure on the Glomerular Filtration Rate in Patients with Obstructive Sleep Apnea Syndrome

Objective Previous studies have shown a possible role for obstructive sleep apnea syndrome (OSAS) in the development and/or progression of chronic kidney disease (CKD). However, the impact of treatment for OSAS on CKD has not been clarified. The aim of this study was to investigate the influence of OSAS and the short-term effects of nasal continuous positive airway pressure (CPAP) on the estimated glomerular filtration rate (eGFR). Methods We evaluated 38 men with OSAS diagnosed on polysomnography. The associations between the eGFR and patient characteristics, including polysomnographic parameters, were evaluated. A multivariate linear regression analysis was performed to determine the independent variables associated with eGFR. We reassessed the polysomnographic data and eGFR values after three months of CPAP treatment. Results The mean serum creatinine level was 0.83 +/- 0.10 mg/dL and the mean eGFR was 77.3 +/- 12.0 mL/min/1.73 m(2). A univariate analysis revealed that an older age (p<0.001), a longer mean apnea duration (p=0.006) and BMI (p=0.022) were significantly associated with lower eGFRs. A multivariate linear regression analysis showed that the independent factors associated with lower eGFRs were older age (p<0.001) and a longer mean apnea duration (p=0.048). Three months after CPAP treatment, there were significant decreases in the serum creatinine levels (p=0.013) and increases in eGFR (p=0.014). Conclusion OSAS, especially that associated with an older age and a longer mean apnea duration, may contribute to lowering eGFR values, which can be reversed by CPAP treatment.