Postprandial C-peptide is more relevant to hemoglobin A1c levels and diabetic microvascular complications than fasting C-peptide in type 2 diabetes

Table 3 Logistic regression of diabetic retinopathy

	Model 1		Model 2		Model 3
	OR (95%CI)	P value	OR (95%CI)	P value	OR (95%CI)	P value
FCP	0.999 (0.998-1)	0.005	0.999 (0.998-1)	0.185	0.999 (0.998-1)	0.243
2hCP	0.999 (0.999-1)	< 0.001	0.999 (0.999-1)	0.001	0.999 (0.999-1)	0.002
Delta CP	0.999 (0.999-1)	< 0.001	0.999 (0.999-1)	0.001	0.999 (0.999-1)	0.001
CP ratio	0.999 (0.989-1.009)	0.877	1 (0.989-1.011)	0.986	1 (0.989-1.011)	0.965
FCP/fasting plasma glucose	0.988 (0.981-0.995)	0.001	0.992 (0.984-0.999)	0.034	0.992 (0.984-1)	0.058
2hCP/postprandial blood glucose	0.991 (0.987-0.995)	< 0.001	0.993 (0.988-0.997)	0.001	0.991 (0.986-0.996)	0.001
Delta CP/BG	0.989 (0.984-0.995)	< 0.001	0.991 (0.985-0.996)	0.001	0.99 (0.984-0.997)	0.002
CP/BG ratio	0.987 (0.932-1.046)	0.664	0.989 (0.929-1.053)	0.723	0.991 (0.941-1.044)	0.736

BG: Blood glucose; CP: C-peptide; FCP: Fasting C-peptide; Model 1: Unadjusted; Model 2: Adjusted for duration, creatinine and alanine transaminase; Model 3: Adjusted for model 2 plus hemoglobin A1c; OR: Odds ratio; 2hCP: 2 hours postprandial C-peptide.