Diagnostic Significance of Excercise-Induced Urinary Albumin Measurement in Children with Type 1(Insulin Dependent) Diabetic Children

Kim, Duk Hee; Shin, Hae Jung; Park, So Mee; Yun, Ho Young; Park, Mi Jung; Kim, Ho Seung

Abstract

PURPOSE
Urine examination for microalbuminuria during the clinical silent years can help to identify those patients most likely to progress to overt nephropathy. The normalization of the AER(Albumin Excretion Rate) by alteration of glomerular hemodynamics may be the key to preventing or delaying overt nephropathy. The prognostic and therapeutic implications have led to attempts to identify patients with microalbuminuria as early as possible.Because diagnosis of microalbuminuria has required a 12 or 24 hour urine collection,there has been interested in developing tests that might serve as a first-stage screen for microalbuminuria. Most reports have dealt with the usefulness of either the albumin concentration or the albumin/creatinine ratio in a timed or randomly collected urine specimen. Exercise induced albumin excretion is increased compared to resting and could unmask latent glomerular damage. The purpose of this study is to evaluate diagostic significance of urinary albumin measurement after exercise in children with insulin dependent diabetes.
METHODS
Fifty-seven patients with IDDM collected their overnight urine from 22:00 to 6:00 in following morning. Exercised method for urine examination was 100M running and collected 2 hour urine after exercise. The AER and Albumin/ creatinine ratio(ACR) were measured in the urine and compared with before and after exercise.
RESULTS
Mean ages of diabetic children was 13.7 yrs old and duration of diabetes was 4.1+/-2.7yrs, HbA1c 8.6+/-1.9%,Systolic BP 107+/-10mmHg and Diastolic BP 67+/-8mmHg. The exercise induced AER was increased compared to before exercise(10.3+/-10.5 vs 18.1+/-16.0 mg/24hr). The exercise induced ACR also increased too(1.4+/-1.5 mg/g.Cr vs 4.1+/-3.6mg/g.Cr)(P<0.01). Two(3.5%) children with IDDM was positive for microalbuminuria in terms of AER before exercise and 8 children(14%) after exercise. No one positive for microalbuminuria in terms of Alb/cr before and after exercise. The charateristics of 8 children with microalbuminuria after exercise was no specific difference between positive and negative microalbuminuria. There was specific correlation between microalbuminuria and HbA1c(P<0.05) but sex, ages, duration of diabetes & blood pressure were not correlated with incidence of microalbuminuria.
CONCLUSION
The mean timed urinary albumin excretion after exercise was significantly higher than before exercise. Measurement of timed urinary albumin excretion after exercise will be helpful for detecting microalbuminuria earlier.