Statistical analysis

Allele discrimination plots were visualized using StepOne Software version 2.2 (Applied Biosystems, Foster City, California, USA). We used IBM SPSS Statistics for Windows version 21.0 (IBM Corp., Armonk, New York, USA) for statistical analysis. Continuous variables were compared using Student’s t-test or Mann–Whitney’s U test. Chi-square test was used to compare discrete variables. We used logistic regression analysis to analyze the relationship between rs7069102 polymorphism and DN after adjusting for systolic pressure, triglycerides, HbA1c, AH, duration of AH, DR, carotid disease, and diabetic foot. The value of p < 0.05 was considered statistically significant. Fisher’s exact test was used to determine the deviation from the Hardy–Weinberg equilibrium (HWE) (http://ihg.gsf.de/).