Indirect bilirubin is inversely associated with diabetic retinopathy risk and is a potential predictive biomarker

Table 2 Multivariate analysis of the association between bilirubin indices and the risk of developing diabetic retinopathy

Variables	Model 1		Model 2		Model 3
	OR (95%CI)	P value	OR (95%CI)	P value	OR (95%CI)	P value
IBIL	0.423 (0.361-0.496)	< 0.001b	0.480 (0.407-0.565)	< 0.001b	0.500 (0.363-0.686)	< 0.001b
DBIL	0.480 (0.365-0.630)	< 0.001b	0.637 (0.486-0.834)	0.001a	1.029 (0.860-1.231)	0.754
TBIL	0.568 (0.507-0.636)	< 0.001b	0.634 (0.565-0.712)	< 0.001b	0.837 (0.693-1.011)	0.837

^aP < 0.01.

^bP < 0.001.

Statistical significance was determined at a P value < 0.05. Multivariate logistic regression analysis was conducted to identify independent risk factors for the development of diabetic retinopathy. Model 1: Adjusted for age. Model 2: Adjusted for age and duration of diabetes. Model 3: Adjusted for age, duration of diabetes, systolic blood pressure, the estimated glomerular filtration rate, the albumin/creatinine ratio, and 1,25(OH)₂D₃. IBIL: Indirect bilirubin; DBIL: Direct bilirubin; TBIL: Total bilirubin; OR: Odds ratio; 95%CI: 95% confidence interval.