The results showed that the predictors of CIN were diabetes (OR = 5.01, 95% CI 2.04–12.35, P < 0.001), baseline BNP (OR = 1.003, 95% CI 1.001–1.004, P = 0.001), baseline cystatin C (OR = 17.48, 95% CI 3.61–84.74, P < 0.001), and CM dosage (OR = 1.009, 95% CI 1.004–1.014, P = 0.001), whereas BMI was not significantly associated with the incidence of CIN (P = 0.197) (Table 4). The gene discussed is CST3; the disease is diabetes mellitus.