Objectives Serum cystatin C has been proposed as a better marker of glomerular filtration rate than serum creatinine. SYNTAX score (SXscore) can accurately reflect the severity of coronary artery disease (CAD). However, the association between Cystatin C-based glomerular filtration rate (eGFR_cys) and SXscore in patients with diabetes has never been reported.

Methods We prospectively included 656 consecutive patients with diabetes who underwent coronary angiography (CAG) and were angio graphically diagnosed with CAD from January 2010 to December 2011. Renal function was assessed by eGFR_cys. SXscore was calculated using a previously described SXscore algorithm. Ordinal logistic regression and Pearson correlation were used to analyse the association between eGFR_cys and SXscore.

Results Patients with renal dysfunction were older, more often female, more likely to have a history of hypertension and less tobacco use when compared with those with normal renal function. Age, sex, SBP, DBP, fasting glucose, HbA1c, TC, LDL, HDL, TG, BMI and CRP were not different among SXscore tertile groups. Incidence of hypertension, hyperlipidemia, family history and tobacco use were similar among these groups. Correlation analysis suggested eGFR_cys was negatively correlated with SXscore (R = -0.255, P< 0.001). Ordinal logistic regression showed that eGFR_cys was an independent predictor of SXscore (B = -0.027, P< 0.001).

Conclusions eGFR_cys was an independent predictor of SXscore in patients with diabetes. Further prospectively multiple centre studies are required to better quantify this finding.