Relationship between the R-R interval variation and metabolic states of diabetes

To investigate whether the metabolic state of diabetes affects the R-R interval variation, 82 diabetics were studied at intervals of about 1 month and of about 1 year. There was no significant relationship between the rate of change for FBG and that for R-R interval variation at both these intervals. However, in the cases that showed a change of HbA1 by more than 10% in a month, the rate of change for the R-R interval variation was 20 +/- 30% in the group with improved HbA1 and -9 +/- 17% in the group with aggravated HbA1, demonstrating a significant difference (P less than 0.05) between the 2 groups. There was a significant difference (P less than 0.02) in the rate of change for the R-R interval variation between the group with improved HbA1 by more than 5% and the group with aggravated HbA1 by more than 5%, when measured at intervals of 1 year. No special relationship was observed between the difference in R-R interval variation and each of the following: (1) the mean FBG for 1 year preceding the day of initial measurement of the R-R interval variation; (2) the mean FBG for the succeeding year; and (3) the difference in these 2. It was suggested that the R-R interval variation was likely to be affected by the metabolic state during the preceding 1-2 months.