Study of the difficult glycemic control in relation to autoantibodies present among patients of Type 1 Diabetes mellitus (Glutamic acid decarboxylase autoantibodies GADA- Islet cells cytoplasmic autoantibodies ICA- Insulin autoantibodies IAA)
Authors: Hamed M S , Samy M , Mahmoud H , Yehia N 
Published: May 2020

Abstract

Background
Type 1 DM is sub-divided into type 1A (immune-mediated) and type 1B (other forms of type 1 DM that include virus-triggered autoimmune response, genetic factors and idiopathic).
It is widely recognized that the presence of two or more auto-antibodies has a high sensitivity and specificity for rapid progression to insulin dependency within 5 years. It is hypothesized that the difficult glycemic control among some type 1 diabetic patients is attributed to the presence of diabetes-autoantibodies.

Aim
This study was designed to assess the relationship between the presence of diabetes autoantibodies and the poor glycemic control developed by patients who receive more than 100 insulin units per day and yet they are not controlled i.e. HbA1c &gt; 7%, elevated plasma glucose level on frequent monitoring although they are non-obese and strictly stuck to healthy diet and exercise, and whether the number of positive autoantibodies affect the glycemic control or not.

Methods
This study was conducted on 60 patients 30 males and 30 females, they were all subjected to full history taking, anthropometric measurements, clinical examination and laboratory assessment in the form of C-peptide, fasting blood glucose, 2 hours post-prandial blood glucose, HbA1c level, serum GADA level, serum ICA level and serum IAA level.
The patients were classified according to presence of diabetes autoantibodies into two groups; Group I consisted of 6 patients (10%) with negative auto-antibodies and Group II consisted of 54 patients (90%) with positive auto-antibodies, Group II was further classified according to the number of positive diabetes autoantibodies into 3 sub-groups, Group II a: Formed of 9 patients with 1 positive autoantibody (16.7% of the study population). Group II b: Formed of 12 patients with 2 positive autoantibodies (22.2% of the study population) and Group II c: Formed of 33 patients with 3 positive autoantibodies (61.1% of the study population).

Results
HbA1c level was significantly higher in group II than group I (11.85 ± 1.61% vs. 8.52 ± 0.41%, p = 0.000). Similarly it was higher in group IIc than group IIb than group IIa (12.25 ± 1.48% vs. 11.57 ± 1.59% vs. 10.78 ± 1.73%, p = 0.038).Moreover HbA1c was significantly higher in patients with positive GADA, patients with positive ICA and those with positive IAA than those with negative GADA, negative ICA and negative IAA (p = 0.000, p = 0.000, p = 0.012 respectively). The total number of insulin units per day was significantly higher in group II than group I (109.83 ± 7.77 U/day vs. 100.83 ± 1.83 U/day, p = 0.007). The duration of diabetes mellitus was significantly higher in group I than group II (10.17 ± 1.94 years vs. 8.11 ± 2.20 years, p = 0.033).
By doing the multivariate regression analyses we found that HbA1c level, total number of insulin units per day and the duration of developing diabetes mellitus were significant predictive factors for the presence of diabetes autoantibodies (p = 0.007, p = 0.033 and p = 0.043 respectively).

Conclusion
The presence of diabetes autoantibodies affect the glycemic control represented by HbA1c level; also it affects the total number of insulin units per day used by the patients; the more the presence of diabetes autoantibodies, the higher the HbA1c level, the more insulin units required by patients to control their glycemic state.