Nocturnal intermittent hypoxia as an associated risk factor for microalbuminuria in Japanese patients with type 2 diabetes mellitus

Objective: We estimated the prevalence of nocturnal intermittent hypoxia, a surrogate marker of obstructive sleep apnoea, among type 2 diabetes mellitus (T2DM) patients and examined the association between nocturnal intermittent hypoxia and microvascular diseases. Design and methods: We recruited 513 Japanese patients (292 men and 221 women) with T2DM. Nocturnal intermittent hypoxia was diagnosed using the 3% oxygen desaturation index, with less than five events per hour corresponding to normal and five events or more per hour corresponding to nocturnal intermittent hypoxia. Results: The prevalence of nocturnal intermittent hypoxia was 45.4% among T2DM patients. The nocturnal intermittent hypoxia group was older and had a higher BMI, greater weight change since the age of 20 years, higher smoking rate and increased prevalence of hypertension, hyperlipidaemia, microalbuminuria and macroalbuminuria. Microalbuminuria (model 1: odds ratio (OR), 3.41; 95% CI, 1.85-6.40; model 2: OR, 3.69; 95% CI, 1.85-7.59 and model 3: OR, 3.12; 95% CI, 1.45-6.95) and nephropathy (model 1: OR, 4.51; 95% CI, 1.58-15.1; model 2: OR, 7.31; 95% CI, 2.11-31.6 and model 3: OR, 5.23; 95% CI, 1.45-23.8) were derived as factors from all the three statistical models and constantly associated with nocturnal intermittent hypoxia only in women. Conclusions: Nocturnal intermittent hypoxia was highly prevalent among T2DM patients and may be an independent associated risk factor for microalbuminuria in Japanese women with T2DM.