CARDIOVASCULAR AUTONOMIC TESTING IN ADOLESCENTS WITH TYPE-I (INSULIN-DEPENDENT) DIABETES-MELLITUS - AN 18-MONTH FOLLOW-UP-STUDY

1. Autonomic abnormalities are frequent in adult patients with diabete s mellitus and progress slowly; little is known about frequency and pr ogression of autonomic abnormalities in childhood. 2. To assess whethe r autonomic abnormalities are already present in childhood, we evaluat ed the cardiovascular reflexes, the spectral analysis of spontaneous f luctuations in RR interval and blood pressure (low- and high-frequency ), and the baroreflex sensitivity at rest, and after vagal (controlled breathing) and sympathetic activation (tilting) in 25 adolescents wit h Type I diabetes mellitus, aged 10-17 years, at baseline and after 18 months follow-up, and in 20 age- and sex-matched controls. 3. Cardiov ascular reflexes were similar in both patients and controls. Similar s ignificant changes in percentage low- and high-frequency (P < 0.005) f rom rest to tilting and to control breathing were observed in both pat ients and controls. The baroreflex sensitivity was also similar in pat ients and controls. Mild and non-systematic correlations were observed between autonomic tests and disease duration or metabolic control. Af ter 18 months follow-up no changes were observed in any of the measure d variables. Correlations with metabolic control remained unchanged. 4 . These results indicate a substantial stability of cardiovascular aut onomic function in childhood diabetes, and suggest that autonomic abno rmalities are likely to develop at an older age.