The cardiovascular form of autonomous neuropathy in the adolescents with type 2 diabetes mellitus

Objective. To estimate the prevalence of the cardiovascular form of autonomous neuropathy (CAN) and the factors associated with this condition in the adolescents suffering from type 2 diabetes mellitus (DM2) in comparison to the adolescents present- ing with type 1 diabetes mellitus (DM1). Material and methods. The study included 24 adolescents with DM2 and 30 ones with DM1 matched for the age, duration of the disease, and the quality of its compensation. The control group was comprised of 17 adolescents with exogenous constitutional obesity (ECO). All the patients were examined by means of Holter ECG monitoring with the estimation of the daily cardiac rhythm variability based on the mean weighted variation of rhythmogram (MWVR) and the length of the QTc interval. In addition, standard cardiovascular tests were performed including deep-breath test, the Valsalva maneuver, and the 30:15 intermittent fitness test. Cardiovascular autonomous neuropathy was diagnosed in the patients exhibiting deviation from the normal values in 3 of the five parameters of interest, viz. MWVR, QTc length, and three functional tests. Results. CAN at the subclincal stage was more frequently diagnosed in the adolescents with DM2 than in those suffering DM1 (29.2 and 10% of the cases respectively; p<0.05). This condition was not found in any of the patients presenting with endogenous constitutional obesity. MWVR in the adolescents with DM2 was lower than in the patients with DM1 (p=0.02) or ECO (p=0.04). The QTc duration was greater in the DM2 patients than in the adolescents of the same age presenting with ECO (p=0.02) and comparable with that in the patients suffering DM1 (p=0.3). In the adolescents with DM2, positive correlation between CAN, the duration of diabetes, the quality of its compensation, and the patient’s age was documented while the length of the QTc interval negatively correlated with these three variables. Moreover, the occurrence of CAN positively correlated with peripheral neuropathy. No relationship with the severity of insulin resistance was observed.