Diabetes-related autoantibodies in diabetic gastroparesis

Detection of islet autoantibodies [anti-glutamic acid decarboxylase antibody (GADA), anti-islet cell antibody (ICA), anti-insulin antibody (IAA)] in patients with diabetes usually indicates an autoimmune origin, suggesting type 1 diabetes (T1DM). The aim of our study was to determine whether islet autoantibodies are present in patients with diabetic gastroparesis and whether they associate with delayed gastric emptying, severity of GI symptoms, or diagnosed type of diabetes.

Patients with diabetic gastroparesis completed: (1) Demographic Questionnaire assessing type of diabetes, associated symptoms and control of glucose and (2) Patient Assessment of GI Symptoms assessing symptoms severity. Blood was drawn for GADA, anti-islet cell ICA-IAA, and Hgb-A1c. Medical records were reviewed for gastric emptying tests and to confirm type of diabetes.

Sixteen patients (12 T1DM; 4 diagnosed T2DM) with diabetic gastroparesis were evaluated. Six of the 16 patients tested positive for GADA, but none were positive for either ICA or IAA. Five of 12 T1DM patients had positive GADA, compared to one of four diagnosed as T2DM. The presence of antibodies was associated with the age of onset of gastroparesis symptoms, but not related to gastric emptying delay, symptom severity, HBA1c levels, or age.

This pilot study demonstrated that of the three tested antibodies in long-term diabetic gastroparesis patients, GADA was the most prevalent positive antibody with no detection of ICA or IAA. Positive GADA was seen in 42 % of T1DM compared to 25 % of phenotypic T2DM. However, the presence of antibody was not associated with severity of gastric emptying or GI symptoms. Thus, detection of an autoimmune form of diabetes, primarily T1DM, should be investigated using GADA.