The first and the second types of diabetes mellitus, autoimmune and non-autoimmune thyroiditis differential diagnosis possibility using the calculated index based on plasma butyrylcholinesterase isoforms activity

BACKGROUND: The possibility of using a diagnostic index based on the use of blood plasma objective indicators to differentiate the diagnosis of type 1 and type 2 diabetes mellitus, autoimmune and non-autoimmune thyroiditis is an urgent task for timely decision-making on the use of a particular type of therapy, taking into account the etiology of a particular pathology. Changing the ratio of blood plasma butyrylcholinesterase isoforms activity makes it possible to identify increased excitability, to separate them among themselves depending on the genesis, and during treatment, to assess the activity of diseases and the effectiveness of therapeutic measures.

AIM: To develop a calculated diagnostic index for the differential diagnosis of diabetes and thyroiditis autoimmune type from symptomatically similar non-autoimmune pathologies, using the ratio of the plasma pseudocholinesterase isoforms activities.

MATERIALS AND METHODS: The study involved 188 people: 45 patients diagnosed with type 1 diabetes; 60 patients diagnosed with type 2 diabetes; 25 patients diagnosed with autoimmune thyroiditis; 25 patients with non-autoimmune thyroiditis; the control group consisted of 33 healthy volunteers. The groups were aligned by gender and age. Patients of all groups were examined by an endocrinologist and a therapeutist. The diagnoses were made in accordance with the Clinical Guidelines of the Russian Endocrinologists Association for the Diagnosis and Treatment of Autoimmune Thyroiditis in Adults, as well as the Clinical Guidelines “Type 1 Diabetes Mellitus in Adults”. In the blood plasma of all patients’ groups, the activity of pseudocholinesterase (butyrylcholinesterase) forms was determined by analysis using a modification of the Ellman’s method in combination with inhibitory analysis. The index was calculated based on the ratio of the studied enzyme typical and atypical forms activities. Based on the results of data analysis for all examined groups, diagnostic intervals were determined that are characteristic for each diagnosis, as well as for conditionally healthy people. Comparison of the patients distribution by categories of diagnosis was carried out using the Χ-square test with Yates correction in the SPSS 22 statistical software package.

RESULTS: The results of the blood plasma analysis determined that in the diagnoses of autoimmune thyroiditis and type 1 diabetes mellitus, there was an increase in the activity of increased activity of the butyrylcholinesterase isoform, while the activity of the atypical form remains more stable. The ratio of these forms was taken as the basis for the development of the calculated diagnostic index. Diagnostic index for the control group in the range of 1–2; for patients with non-autoimmune thyroiditis — 2,1–2,9; autoimmune thyroiditis — 3–3,5; type 1 diabetes mellitus — 3,6–5; type 2 diabetes — 0–1. Statistical analysis of the data showed that the diagnosis based on the index obtained in this way does not inferior to the diagnostic scales in terms of sensitivity and specificity. The findings are consistent with the evolution of data supporting each diagnosis.

CONCLUSIONS: The calculated index on the basis of butyrylcholinesterase activity is a promising, minimally invasive, fast and budgetary method, revealing a pronounced severity of occurrence in terms of symptoms, but different in etiology, type 1 diabetes mellitus and type 2 diabetes mellitus, autoimmune thyroiditis and thyroiditis of a non-autoimmune nature, which is of critical importance when choosing a therapeutic strategy and improving the quality of life of patients.