[Correlation between cognitive impairment and diabetic nephropathy in patients with Type 2 diabetes mellitus]

To explore the correlation between diabetic nephropathy (DN) and cognitive impairment through examining the cognitive function and the metabolism of the cerebrum in Type 2 diabetes mellitus patients at different stages of renal function.

Eighty six patients with Type 2 diabetes mellitus (T2DM) were enrolled for this study. According to the urinary albumin excretion rate (UAER), the patients were divided into a T2DM without DN group (DM group, n=33), an early DN group (DN-III group, n=26) and a clinical stage group (DN-IV group, n=27). Thirty healthy adults were selected as a control group (NC group). Biochemical indexes and UAER were measured, and glomerular filtration rate (GFR) was detected by single-photon emission computed tomography (SPECT). The cognitive function was measured by Montreal Cognitive Assessment (MoCA, Beijing version) and mini-mental state examination (MMSE). The peak areas of N-acetylasparte (NAA), creatine (Cr), choline-containing compounds (Cho) were detected by proton magnetic resonance spectroscopy (1H-MRS).

1) There was no statistical difference in MMSE scores between the DM group and the control group. The scores of MoCA in the DN-III group or in the DN-IV group were significant less than that in the NC group (F=3.66, P<0.05); 2) There was significant difference in left N-acetylaspartate (LNAA), left choline (LCho) among the diabetes groups. Compared with the DM group, the level of LNAA was decreased significantly (t=3.826, P<0.05) while the LCho was increased significantly (t=4.373, P<0.05) in the DN groups, with statistic difference between the 2 groups (t=3.693, P<0.05); 3) The MoCA scores of T2DM patients were negatively correlated with UAER (r=-0.285, P<0.05), while positively correlated with GFR (r=0.379, P<0.05); 4) Logistic regression analysis indicated that UAER and GFR were the major risky factors for diabetic cognitive impairment.

Diabetic cognitive impairment is closely correlated with the nephropathy in patients with Type 2 diabetes. With the decline in glomerular filtration function, the cognitive disorder tends to be aggravated. The hippocampal brain metabolism may have some changes in left side of Cho/Cr in patients with diabetic nephropathy.