Urine albumin to creatinine ratio-response to exercise in diabetes.

Abstract

SUMMARY Albuminuria was studied in 40 diabetic children before and after a standardised exercise test, and also in 21 normal children; the results are expressed as geometric mean (95% range) of urine albumin:urine creatinine ratio (mg/mg). There was no significant difference between the mean resting albumin:creatinine ratio in the two groups, or between these ratios before and after exercise in the normal children. In the diabetic children, however, the mean urine albumin:creatinine ratio after exercise was significantly higher than both the value before exercise and the postexercise value of the normal children, with 10 of 40 diabetic children showing a value after exercise greater than the 95% range of the geometric mean of the control group.The diabetic children were also studied by random urine albumin:creatinine ratios and split (erect:supine) 24 hour urine collection; none was abnormal. Several studies, mainly in adults, have shown that before the onset of overt proteinuria, many diabetics have a higher mean urinary albumin excretion rate than normal subjects, and that this early 'microalbuminuria' is at least partially correctable by strict metabolic control.4 Other studies have delineated low and high risk groups for the development of diabetic nephropathy on the basis of overnight albumin excretion rates before the onset of overt proteinuria.5Exercise increases urinary albumin excretion. During exercise it seems likely that the glomerulus becomes leaky when a higher filtration pressure operates. If the membrane is already abnormal or stressed in some way the increased leak will occur at a lower threshold and to a more noticeable degree. Thus it may be possible to identify a subgroup within the diabetic population at particular risk of developing diabetic nephropathy at the early stage of slightly raised albumin excretion using exercise as a probe to unmask latent glomerular damage.Previous studies have been mainly in adults and have involved the use of albumin clearance or excretion rates;69 these studies are difficult to perform in children because of the problems of collection of accurately timed and measured volumes of urine.The use of the urine albumin: urine creatinine ratio minimises the errors due to variations in the glomerular filtration rate and has been shown to be a useful measure of overall glomerular permeability,'0 although it does not take account of nephron hyperfiltration or tubular reabsorption. The albumin:creatinine ratio on random specimens has been shown to correlate well with the albumin excretion ratel' 11 and has the advantage of not requiring timed and measured urine collection.In this pilot study the urine volumes and collection times for diabetic children were noted and blood samples were taken before the start of exercise to allow comparison between the albumin: 305 on 10 May 2018 by guest. Protected by copyright.

Characterization of Recumbent, Ambulatory, and Postexercise Proteinuria in the Adolescent

“…As all of the previous studies evaluating exercise proteinuria in children or adolescents (1 2-1 5,4 1) have been done using a standard exercise protocol on a bicycle ergometer or treadmill, the results of our study are not strictly comparable to any of these observations. However, mean values for upright and postexerise UA1b/Ucr in our study were not different and were nearly identical to those reported by Jefferson et al (13). However, Brouhard et al (14) reported postexercise values for UAlb/UCr that were somewhat higher.…”

Dosagem de microalbuminúria em hipertensos e em pacientes portadores de doença coronariana

“…The three major limitations for the determination of microalbuminuria are: 1) Strenuous exercise, which may lead to a transient increase in albumin excretion 4 ; 2) Alteration during the day in the relation between the collection of a spot urine sample and the 24-hour collection: there is a better correlation if the samples are obtained in the middle of the morning 5 ; 3) The accuracy of the albumin/creatinine In elderly individuals, the combination of microalbuminuria and hyperinsulinemia, a reflex of insulin resistance, is associated with increased risk of coronary events and mortality 10 .…”

Evaluation of Protein in Dietary Management of Diabetes Mellitus

“…Whether the exercise test can be used to evaluate the role of excess dietary protein or the potential benefit of protein restriction is not known. The exact mechanism causing the increased albuminuria during exercise in incipient nephropathy may be related to microcirculatory changes in the glomeruli and renal autoregulation in connection with arteriolar hyalinosis, but renal tubular alterations are not thought to be involved (41).…”

“…An exercise test has been developed to evaluate the severity of disease and the impact of antihypertensive therapy on renal function and albumin excretion (40)(41)(42)(43)(44)(45)(46)(47)(48). Whether the exercise test can be used to evaluate the role of excess dietary protein or the potential benefit of protein restriction is not known.…”