Decreased microcirculatory function measured by perfusion index is a novel indicator of diabetic kidney disease in patients with type 2 diabetes

AIMS/INTRODUCTION: Diabetic kidney disease has been considered as an important risk factor of cardiovascular disease. Chronic hypoxia is considered to be the main cause of renal injury. Diminished microcirculatory blood flow could be associated with hypoxia in the kidney. Whether diminished microcirculation is associated with diabetic kidney disease has not yet been reported. Here, we investigated the correlation between microcirculatory function and diabetic kidney disease in patients with type 2 diabetes. MATERIALS AND METHODS: Our cross‐sectional study included 574 patients who were admitted to Matsushita Memorial Hospital in Moriguchi, Japan, for type 2 diabetes. Microcirculatory function was assessed using the perfusion index (PI), which represents the level of circulation through peripheral tissues. We measured the PI for all patients. RESULTS: The median age and PI values were 70 years (range 60–77 years) and 2.8% (range 1.6–4.8%). Multiple regression analyses showed that the PI independently correlated with the logarithm of urinary albumin excretion (P = 0.009) and estimated glomerular filtration rate (P = 0.005), respectively. Multiple logistic regression analyses showed that patients with systolic blood pressure (SBP) greater than the median and PI less than or equal to the median (high‐low group) had a significantly increased odds of albuminuria compared with those with SBP less than or equal to the median and PI greater than the median (low‐high group), and patients with SBP greater than the median and PI less than or equal to the median (high‐low group) had a significantly increased odds of estimated glomerular filtration rate <60 mL/min per 1.73 m(2) compared with those with SBP less than or equal to the median and PI greater than the median (low‐high group) or SBP greater than the median and PI greater than the median (high‐high group). CONCLUSIONS: PI could be a novel indicator of diabetic kidney disease in patients with type 2 diabetes.