Effect of exercise on albuminuria in people with diabetes

Spot urine measurement of albumin is now the most commonly accepted approach to screening for proteinuria. Exertion prior to the collection may potentially influence the result of spot urine albumin estimation. We aim to evaluate the effect of exercise on albuminuria in subjects at various stages of diabetic nephropathy in comparison with healthy control volunteers.

Thirty-five people with diabetes (19 with normoalbuminuria (NA), nine with microalbuminuria (MA) and seven with overt proteinuria (OP)) and nine control subjects were assessed. A 1 km treadmill walk was performed. Four spot urine specimens were collected: first morning void, immediately prior to exercise, and 1 h and 2 h after exercise. A random effects linear regression mixed model was used to assess the effect of exercise on albumin/creatinine ratio (uACR). Results are presented separately for male and female subjects with diabetes due to a significant exercise/gender interaction (P < 0.05).

No significant effect of exercise on uACR was seen in control subjects. In NA males with diabetes no effect of exercise was seen, while in females uACR 1 h after exercise was significantly higher than the early morning sample (3.55 mg/mmol (96% confidence interval 0.27-6.83). Both female and male diabetes subjects with MA have increase in uACR 1 h after exercise (87.8, -24.3-199.4 and 6.7, 2.1-11.3). For both males and females with OP, uACR was significantly increased 1 h post exercise (67.5, 22-113 and 21.6, 8.4-34.8, respectively). In all groups uACR at 2 h after exercise was not significantly different to the early morning sample.

Exercise increased uACR estimation in normoalbuminuric subjects with diabetes with a larger effect in females. Whether exercise unmasks early diabetic nephropathy in NA subjects requires further study.