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Cardiovascular reflex abnormalities in children and adolescents with diabetes mellitus
R E Ringel1, S A Chalew, K A Armour
1Department of Pediatrics, University of Maryland School of Medicine, Baltimore.
Insights
Cardiovascular reflex tests detected abnormalities in 29% of children with type 1 diabetes. These simple tests can monitor autonomic neuropathy in pediatric diabetes patients.
Area of Science:
- Pediatric Endocrinology
- Cardiovascular Physiology
- Diabetic Complications
Background:
- Abnormal cardiovascular reflexes are a common complication in adult diabetes, increasing morbidity and mortality.
- Assessing these reflexes in children with type 1 diabetes is crucial for early detection and management.
Purpose of the Study:
- To evaluate the effectiveness of specific cardiovascular reflex tests in children.
- To determine the prevalence of cardiovascular reflex abnormalities in children with insulin-dependent diabetes mellitus (IDDM).
Main Methods:
- Heart-rate responses to deep breathing (HR-DB) and standing (HR-STND) were measured in children aged 6-19 with and without IDDM.
- Specific metrics like corrected heart-rate change (HR-DBc) and expiration-inspiration ratio (E:I) for deep breathing, and the Maximum-minimum ratio (M/m) for standing were used.
- A subgroup of IDDM patients was retested after one year to assess test-retest reliability.
Main Results:
- 29% of children with IDDM exhibited abnormal cardiovascular reflex responses (HR-DBc or HR-STND M/m).
- Abnormalities were found in 21% for deep breathing tests (HR-DBc or E:I) and 11.4% for standing tests (HR-STND M/m).
- No correlation was observed between reflex abnormalities and HbA1c levels or diabetes duration, but tests showed high reliability over one year.
Conclusions:
- Easily performed cardiovascular reflex tests can identify autonomic neuropathy in 29% of children with IDDM.
- These tests offer an objective method for monitoring autonomic function in pediatric diabetes.
- The findings highlight the importance of regular screening for cardiovascular reflex abnormalities in children with diabetes.
Objective:
To assess the usefulness of specific cardiovascular reflex tests in childhood and to estimate the prevalence of cardiovascular reflex abnormalities among children with IDDM. In adults, abnormal cardiovascular reflexes are a frequent complication of diabetes, associated with increased morbidity and mortality.
Research Design And Methods:
We measured heart-rate responses to deep breathing and standing in ambulatory children with and without IDDM between 6-19 yr of age. A subgroup of the IDDM patients was retested after 1 yr.
Results:
We found the best techniques for detecting cardiovascular reflex abnormality in children were as follows: to record heart-rate responses to deep breathing either as the change in heart rate corrected for inspiratory heart rate or as the ratio of R-R intervals during expiration and inspiration; and to use the Maximum-minimum ratio for heart-rate responses to standing. HR-DBc was lower in diabetic than nondiabetic children (28.6 +/- 9.2% [n = 248] vs. 33.6 +/- 6.8% [n = 60]; P < 0.0005). Similarly, E:I was lower in children with IDDM than control subjects (1.42 +/- 0.19 [n = 248] vs. 1.52 +/- 0.15 [n = 60]; P < 0.0005). In the IDDM group, 21% of the children had abnormal HR-DBc or E:I responses. HR-STND M/m was lower in children with IDDM than control subjects (1.28 +/- 0.20 [n = 167] vs. 1.38 +/- 0.22 [n = 45]; P < 0.014). Among children with IDDM, 11.4% had abnormal HR-STND M/m responses. Overall, 29% of IDDM children tested abnormal in either HR-DBc or HR-STND M/m; 3% were abnormal in both tests. We found no correlation of HbA1c levels (n = 74) or duration of diabetes with either HR-DB, expiration to inspiration (n = 248), or HR-STND M/m (n = 167). In patients who were reevaluated after 1 yr we found a high correlation of the first and repeat HR-DBc tests (r = 0.47, n = 75, P < 0.0001), E:I (r = 0.53, n = 75, P < 0.0001), and HR-STND M/m (r = .49, n = 37, P < 0.002), but no evidence of an increased number of children with cardiovascular reflex abnormality.
Conclusions:
With easily performed HR-DB and HR-STND tests, we detected cardiovascular reflex abnormality in 29% of children with IDDM. We found no correlation of changes in HR-DB and HR-STND with HbA1c or duration of diabetes. These tests provide an objective clinical measurement to monitor autonomic neuropathy in children with diabetes.