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Postexercise albuminuria in children with different duration of type-1 diabetes mellitus
M Krüger1, N Gordjani, R Burghard
1Children's Hospital, University of Freiburg, Germany.
Insights
Exercise stress testing reveals early kidney damage in children with diabetes. A significant increase in albuminuria after exercise indicates potential glomerular damage, even when resting tests are normal.
Area of Science:
- Nephrology
- Pediatric Endocrinology
- Diabetology
Background:
- Diabetic nephropathy is a major complication affecting 30% of diabetic patients.
- Early detection of kidney damage in children with diabetes is crucial for intervention.
- Exercise can unmask subclinical renal abnormalities.
Purpose of the Study:
- To investigate exercise-induced changes in albumin excretion in diabetic children without clinical signs of nephropathy.
- To assess the utility of exercise testing in identifying early-stage kidney damage in pediatric diabetes.
Main Methods:
- Compared albumin excretion rate (AER) and albumin-to-creatinine ratio before and after exercise in 39 diabetic children and 21 healthy controls.
- Categorized diabetic patients based on disease duration (DI < 5 years, DII 5-10 years, DIII > 10 years).
- Measured urinary IgG and transferrin excretion in a subset of patients.
Main Results:
- Healthy children showed no increase in AER post-exercise.
- Diabetic children with disease duration > 5 years exhibited a significant increase in albuminuria after exercise.
- 43% of these patients also showed urinary IgG and transferrin excretion, suggesting glomerular damage.
- No correlation found between albuminuria and metabolic control (HbA1c) or renal function parameters.
Conclusions:
- Exercise testing can reveal exercise-induced albuminuria in diabetic children, indicating early kidney damage.
- This damage may be present even when resting albumin excretion rate is normal.
- Urinary IgG and transferrin excretion further support structural glomerular alterations in affected children.
Abstract:
About 30% of diabetic patients develop progressive renal failure. We studied albumin, IgG, and transferrin excretion during exercise in diabetic children without signs of nephropathy to investigate proteinuria under these conditions: 39 patients with insulin-dependent diabetes mellitus and 21 healthy children undertook a bicycle exercise test. Albuminuria measured by nephelometry was calculated as the albumin excretion rate (AER) and albumin-to-creatinine ratio before and after exercise. The diabetic group was divided into three subgroups according to disease duration (DI < 5 years, DII 5-10 years, DIII > 10 years). No significant difference in metabolic control (hemoglobin A1c was detected between the diabetic groups (median hemoglobin A1c: DI 7.2%, DII 7.6%, DIII 8.6%). There was no increase in AER in the healthy children after exercise. Before exercise the diabetic groups had an AER similar to controls. No significant increase in albuminuria after exercise was seen in group DI. Both groups with a disease duration of more than 5 years had a significant increase in albuminuria [median before/after: DII 7.8/16.7 (P < 0.05), DIII 0/57.9 (P < 0.05) micrograms/min per 1.73 m2). Of these patients, 43% also had a measurable urinary excretion of IgG and transferrin, indicating structural glomerular damage. There was no correlation of albuminuria and parameters of metabolic control or renal function. We conclude that in diabetic children an exercise test unveils albuminuria in certain patients, while their AER may be normal at rest.