The Ratio of Estimated Glomerular Filtration Rate Based on Cystatin C and Creatinine Reflecting Cardiovascular Risk in Diabetic Patients

Background: The ratio of estimated glomerular filtration rate (eGFR) based on cystatin C and creatinine (eGFR(cystatin C)/eGF(Rcreatinine) ratio) is related to accumulating atherosclerosis-promoting proteins and increased mortality in several cohorts. Methods: We assessed whether the eGFR(cystatin C)/eGF(Rcreatinine)ratio is a predictor of arterial stiffness and sub-clinical atherosclerosis in type 2 diabetes mellitus (T2DM) patients, who were followed up during 2008 to 2016. GFR was estimated using an equation based on cystatin C and creatinine. Results: A total of 860 patients were stratified according to their eGFR(cystatin C)/eGF(Rcreatinine)ratio (i.e., <0.9, 0.9-1.1 [a reference group], and >1.1). Intima-media thickness was comparable among the groups; however, presence of carotid plaque was frequent in the <0.9 group (<0.9 group, 38.3%; 0.9-1.1 group, 21.6% vs. >1.1 group, 17.2%, P<0.001). Brachial-ankle pulse wave velocity (baPWV) was faster in the <0.9 group (<0.9 group, 1,656.3 +/- 333.0 cm/sec; 0.9-1.1 group, 1,550.5 +/- 294.8 cm/sec vs. >1.1 group, 1,494.0 +/- 252.2 cm/sec, P<0.001). On comparing the <0.9 group with the 0.9-1.1 group, the multivariate-adjusted odds ratios of prevalence of high baPWV and carotid plaque were 2.54 (P=0.007) and 1.95 (P=0.042), respectively. Cox regression analysis demonstrated near or over 3-fold higher risks of the prevalence of high baPWV and carotid plaque in the <0.9 group without chronic kidney disease (CKD). Conclusion: We concluded that eGFR(cystatin C)/eGF(Rcreatinine)ratio < 0.9 was related to an increased risk of high baPWV and carotid plaque in T2DM patients, especially, those without CKD. Careful monitoring of cardiovascular disease is needed for T2DM patients with low eGFR(cystatin C)/eGF(Rcreatinine)ratio.