The influencing factors of HbA 1C variability and its effect on diabetic retinopathy in patients with type 2 diabetes / 中华内分泌代谢杂志

ABSTRACT

Objective:To investigate the relationship between HbA 1C variability and diabetic retinopathy(DR) in patients with type 2 diabetes and to explore the influencing factors of HbA 1C variability. Methods:Type 2 diabetic patients who received dilated funduscopic examination annually, were stratified into two groups based on the presence or absence of DR, with a median follow-up period of 4 years(2-5 years). Intrapersonal means and SDs of all recorded HbA 1C measurements were calculated. A 1C-SD represented the measure of HbA 1C variability. In addition, medical history and clinical data of all subjects were collected and analyzed. Subjects were divided into four quartiles based on their A 1C-Mean and A 1C-SD data Q1(A 1C-Mean<7%, A 1C-SD<0.76%); Q2(A 1C-Mean<7%, A 1C-SD≥0.76%); Q3(A 1C-Mean≥7%, A 1C-SD<0.76%); Q4(A 1C-Mean≥7%, A 1C-SD≥0.76%). Results:Multivariate linear regression showed that exercise, insulin( P<0.01), and smoking( P=0.004) are the influencing factors of HbA 1C variability. Adjusted for age, sex, and diabetes duration, Cox regression analysis revealed that HbA 1C variability was an independent risk factor for DR. Meanwhile, patients in Q4 group had the highest DR prevalence(HR=1.676, P<0.01) while Q1 group had the lowest. In addition, patients in Q2 group(HR=1.437, P=0.005) had a higher risk of DR than those in Q3 group(HR=1.361, P<0.01). Conclusions:HbA 1C variability is an independent predictor of DR in patients with type 2 diabetes. It may play a greater role in DR development than mean HbA 1C does when the mean value of HbA 1C variability index is above 0.75%.