Early markers of renal damage in obstructive sleep apnea syndrome (OSAS) patients with or without diabetes mellitus

Abstract Background Although obstructive sleep apnea syndrome (OSAS) has been associated with chronic kidney disease CKD, there are little data about early screening of renal affection in OSAS patients. Aim of the work To evaluate renal function in OSAS patients with or without diabetes mellitus (DM) using blood indices [mean platelet volume (MPV) and red cell distribution width (RDW)] and serum neutrophil gelatinase associated lipocalin (NGAL) as early markers of kidney injury. Patients and methods This case control analytic study was designed to enroll 20 OSAS patients with DM, 20 OSAS patients without DM, and 20 non OSAS diabetic patients as control group. All patients underwent full over-night attended diagnostic polysomnography. Those with AHI ≥5 were considered to have OSAS. Laboratory parameters including complete blood count with MPV and RDW, serum glucose, urea, creatinine, Hemoglobin A1c, urine albumin creatinine ratio UACR and serum NGAL were done to all enrolled participants. Results Urine albumin creatinine ratio UACR ≥ 3 mg/mmol was found in 11 (55%) of OSAS diabetic group, 6 (30%) of non diabetic OSAS group and in 11 (55%) of D.M group. Both diabetic and non diabetic OSAS patients had significantly higher RDW and NGAL compared to non OSAS diabetic. The diabetic OSAS group had also significantly higher serum urea and creatinine compared to DM group. In OSAS patients, RDW had significant positive correlation with UACR. Meanwhile both RDW and NGAL were determined to have significant positive correlation with desaturation index during sleep, but not correlated to AHI. Conclusion Renal impairment is common in OSAS patients but more frequent if associated with diabetes mellitus. RDW% can be used as simple screening test for early detection of renal injury in OSAS patients with or without diabetes mellitus.