Obstructive sleep apnea is associated with impaired renal function in patients with diabetic kidney disease

Abstract

Obstructive sleep apnea (OSA) is a recognized risk factor for the development of diabetic kidney disease (DKD). Our objectives were to compare the urinary albumin-creatinine ratio (UACR) and estimated glomerular filtration rate (eGFR) of patients with DKD according to OSA severity, and to evaluate the contribution of sleep parameters to their renal function. In a multicenter, observational, cross-sectional study, 214 patients with DKD were recruited. After a sleep study, UACR and eGFR were measured, as well as serum creatinine, fasting glucose, glycated hemoglobin, insulin resistance, lipid profile and C-reactive protein. UACR was higher in severe OSA patients (920 ± 1053 mg/g) than in moderate (195 ± 232 mg/g, p < 0.001) or mild OSA/non-OSA subjects (119 ± 186 mg/g, p < 0.001). At the same time, eGFR showed an OSA severity-dependent reduction (48 ± 23 vs. 59 ± 21 vs. 73 ± 19 ml/min per 1.73 m², respectively; p < 0.001). Apnea-hypopnea index (AHI and desaturation index (ODI) were identified as independent predictors for UACR and eGFR, respectively. Therefore, in patients with DKD under optimized treatment, severe OSA is associated with a higher UACR and a lower eGFR, reflecting an additional contribution to the impairment of their renal function, although no causality can be inferred.

Figure 1

Box-and-whisker plots depicting the distribution of (a) urinary albumin–creatinine ratio and (b) estimated glomerular filtration rate of patients with diabetic kidney disease according to OSA severity. The dark line in the middle of the boxes represents the median and the length of the box reflects the interquartile range (IQR). The T-bars represent maximum and minimum values. Comparisons performed using SPSS 26.0 software (SPSS Inc., Chicago, IL, USA).

Figure 2

Relationship between the sleep characteristics and the urinary albumin–creatinine ratio (UACR) in patients with diabetic kidney disease. Data are log transformed. ESS Epworth sleepiness scale, AHI apnea–hypopnea index, ODI desaturation index, SaO₂ oxygen saturation.

Figure 3

Relationship between the sleep characteristics and the estimated glomerular filtration rate (eGFR) in patients with diabetic kidney disease. Data are log transformed. AHI apnea–hypopnea index, ODI desaturation index, SaO₂ oxygen saturation.