Comparative characteristics of the functional state of the cardiovascular system in diabetes mellitus and obesity in children

The dissertation is devoted to a comparative study of the functional state of the cardiovascular system in children with diabetes mellitus and obesity. The work is aimed at identifying the features of autonomic homeokinesis, the circadian changes of heart rate and blood pressure, and intracardiac haemodynamics in these endocrinopathies in childhood. Regional centile tables for the assessment of blood pressure have been developed for the Tver region, and the frequency of arterial hypertension in the examined children has been determined.

The study evaluated the possibilities of correcting the revealed disorders with the help of metabolic preparations — Dibikor in diabetic autonomic cardiovascular neuropathy in children with diabetes mellitus and Siofor in metabolic cardiomyopathy in children with obesity. The results obtained are of importance for the early diagnosis of cardiovascular complications and for the improvement of rehabilitation programmes for this category of patients.

Diabetes mellitus and obesity are among the most common endocrinopathies of childhood.

According to WHO data, the number of patients with diabetes mellitus doubles every 15 years, and by 2010 their number will exceed 230 million people. The proportion of children among patients with diabetes mellitus ranges, according to various authors, from 3.8 to 8%.

At present, in the developed countries of the world, up to 25% of adolescents are overweight, and 15% suffer from obesity. According to V.A. Peterkova (2004), in the Russian Federation 5.5% of children living in rural areas and 8.5% in urban areas are obese; 30-50% of children with obesity retain this disease in adulthood.

Diabetes mellitus and obesity represent a serious medical and social health-care problem in all countries of the world, which is caused by the high risk of developing cardiovascular complications and the early disability of such patients [32,72].

The cardiovascular complications in diabetes mellitus and obesity identified in adults begin to form in childhood. A shift of preventive measures to the early periods of ontogenesis will allow a more successful prevention of the progression of cardiovascular complications. Timely diagnosis of the initial stages of cardiovascular complications in diabetes mellitus and obesity in children will improve the quality and increase the life expectancy of such patients.

The wide prevalence of cardiovascular complications in diabetes mellitus and obesity requires a comprehensive cardiological examination with the use of modern instrumental methods of examination, which will allow a better understanding of the mechanisms underlying the development of cardiovascular complications.

The close association between diabetes mellitus, obesity and cardiovascular complications gives grounds to assume the presence of common mechanisms underlying the formation of cardiac pathology in these diseases. A comparative characterization of the functional state of the cardiovascular system in diabetes mellitus and obesity in children will allow a better understanding of the mechanisms of adaptation of the child's organism under conditions of altered metabolism, which will ensure the development and practical application of more effective rehabilitation programmes for such patients.

The accumulated evidence on metabolic disturbances in diabetes mellitus and obesity currently requires the inclusion in the therapy of these diseases of agents that normalize metabolic processes. Antioxidant preparations in diabetes mellitus and insulin sensitisers in obesity are among the promising medicinal agents used to correct metabolic processes. It seems expedient to study the effect of these substances on the functional state of the cardiovascular system in diabetes mellitus and obesity.

All this determined the aim of the present study and defined its tasks.

AIM

To carry out a comparative analysis of the functional state of the cardiovascular system in diabetes mellitus and obesity in children.

TASKS

1. To establish the features of autonomic homeokinesis in children with diabetes mellitus and obesity.

2. To evaluate the circadian changes of heart rate and blood pressure in diabetes mellitus and obesity in children.

3. To determine the features of intracardiac haemodynamics in diabetes mellitus and obesity in children.

4. To evaluate the possibility of correcting disorders of the functional state of the cardiovascular system in diabetes mellitus and obesity in children with the help of metabolic preparations.

SCIENTIFIC NOVELTY

For the first time in the Tver region, centile tables have been developed for detecting high normal blood pressure and arterial hypertension depending on age, sex and somatotype in children; the frequency of arterial hypertension in diabetes mellitus and obesity in children has been established.

For the first time, early signs of metabolic cardiomyopathy have been revealed in children with obesity: decreased sensitivity of the sinus node to parasympathetic influences, enhancement of the rhythm concentration function, increased variability and an inadequate nocturnal fall in BP.

For the first time, the effectiveness has been demonstrated of the use, in the combined cardiometabolic therapy of children with diabetes mellitus, of the preparation Dibikor for the treatment of diabetic autonomic cardiovascular neuropathy and of the preparation Siofor for the treatment of metabolic cardiomyopathy.

PRACTICAL SIGNIFICANCE

The regional centile tables created by us allow the diagnosis of high normal blood pressure and arterial hypertension in children.

Timely diagnosis of the early stages of cardiovascular complications in diabetes mellitus and obesity allows the prevention of their further progression.

The inclusion of the preparation Dibikor in the combined therapy of diabetes mellitus and of the preparation Siofor in the combined therapy of obesity makes it possible to correct disorders of the functional state of the cardiovascular system in children.

IMPLEMENTATION INTO PRACTICE

The results of the investigation have been implemented in the practice of Children's Hospitals No. 1 and No. 2 of the city of Tver. The materials of the work are used in teaching students of the paediatric faculty and clinical residents of the Tver State Medical Academy.

Two patents for inventions have been obtained based on the materials of the work:

- No. 2242918 of 27 December 2004 "Method for the differential diagnosis of elevated blood pressure and the early diagnosis of arterial hypertension in adolescents" (co-authors: S.F. Gnusaev, D.A. Ivanov);

- No. 2261654 of 10 October 2005 "Method for the pre-clinical diagnosis of diabetic autonomic cardiovascular neuropathy in children and adolescents" (co-authors: S.F. Gnusaev, O.A. Dianov).

Three certificates for rationalization proposals have been obtained at the State Educational Institution of Higher Professional Education "Tver State Medical Academy of the Federal Agency for Health Care and Social Development" (No. 2547 of 28 November 2003, No. 2548 of 28 November 2003, No. 2549 of 28 November 2003).

In co-authorship with Professor S.F. Gnusaev and Associate Professor O.A. Dianov, a manual for physicians "Diagnosis and Correction of Metabolic Cardiomyopathy in Children with Obesity" was developed and approved on 28 April 2005 by the Paediatrics Section of the Scientific Council of the Ministry of Health of the Russian Federation.

APPROBATION OF THE WORK

The main propositions of the dissertation were reported and discussed at the Russian National Congress of Cardiologists (Moscow, 2003), the IX Congress of Paediatricians of Russia (Moscow, 2004), the All-Russian Congress "Children's Cardiology 2004" (Moscow, 2004), the X Congress of Paediatricians of Russia (Moscow, 2005), the XII All-Russian Congress "Man and Medicine" (Moscow, 2005), and the conference of the paediatric-profile departments of the Tver Medical Academy.

The dissertation was approved at the extended departmental meeting of the Department of Paediatrics of the Paediatric Faculty on 11 May 2006.

The results of investigations on the topic of the dissertation have been published in 19 printed works.

VOLUME AND STRUCTURE OF THE DISSERTATION

The dissertation is set out on 156 pages of typewritten text and consists of an introduction, five chapters, a discussion of the results and conclusion, conclusions, practical recommendations and a list of references containing 102 works by domestic and 93 works by foreign authors. The dissertation is illustrated with 50 tables, 10 figures and 4 case-record extracts.