Patients with type 2 diabetes mellitus (T2DM) and diabetic kidney disease (DKD) remain at high risk of kidney function decline and mortality. The contribution of obstructive sleep apnea (OSA) to long-term renal outcomes in this population remains uncertain. 

An observational cohort study published in Diabetic Medicine evaluated this relationship in approximately 120 patients with estimated glomerular filtration rate (eGFR) <60 mL/min/1.73 m² and elevated urine albumin-to-creatinine ratio (UACR), who were not on renal replacement therapy. OSA status was assessed using the apnea–hypopnea index (AHI) from a portable home sleep device. Forty-one patients had no OSA (AHI <5), and 36 had moderate-to-severe OSA (AHI ≥15). Longitudinal eGFR and UACR data were analyzed from up to 5 years before OSA assessment through a median follow-up of 3.2 years.

Baseline characteristics, including age, eGFR (32.2 vs 32.9 mL/min/1.73 m²), medication use, blood pressure, lipid levels, and glycemic control, were comparable between groups. Patients with OSA had higher body mass index (BMI) and UACR at baseline. Adjusted analysis showed a greater decline in eGFR from 5 years before the end of follow-up in patients with OSA compared with those without OSA (p=0.016).

OSA was also associated with a higher risk of CKD progression, defined as more than 50% decline in eGFR or need for renal replacement therapy (adjusted hazard ratio [aHR] 3.4; 95% CI 1.3-9.1). The composite endpoint of CKD progression or death occurred more frequently in the OSA group (aHR 3.2; 95% CI 1.3–7.7), with findings remaining robust after adjustment for age, sex, eGFR, UACR, BMI, and blood pressure. These findings suggest OSA may be an important factor in risk stratification in DKD. Randomized studies are required before these findings inform clinical practice.