How to predict nephropathy in type 1 diabetic patients
Routine data or provocation by exercise testing?

Abstract

Objective: Do exaggerated increases in blood pressure and albuminuria during exercise occur earlier than microalbuminuria and which type of test is most predictive of diabetic nephropathy?

Material and Methods: A total of 33 insulin‐dependent normoalbuminuric men (mean duration of diabetes 14 years; mean age 28 years) and 34 age‐matched apparently healthy control subjects were studied. Urinary albumin excretion, heart rate and blood pressure were measured during fixed workload (150 W) and fixed heart rate (155 beats/min) tests. Mean follow‐up time was 13.1 ± 3.2 years. A urinary albumin level in early‐morning urine persistently >30 mg/l was considered a sign of diabetic nephropathy.

Results: Sixteen patients reached the endpoints of the study. Eleven had developed microalbuminuria and five macroalbuminuria (persistent levels of urinary albumin >300 mg/l). Of the latter patients, two needed dialysis. Systolic blood pressure and albumin excretion during the fixed heart rate test were higher in diabetic patients who developed signs of nephropathy than in control subjects and diabetic subjects with persistent healthy kidneys. Such differences were not found in the fixed workload test. There were no differences in glycated haemoglobin, blood pressure levels or albumin excretion at baseline between the two diabetic groups.

Conclusions: To predict the development of diabetic nephropathy it seems important to choose a fixed heart rate test. High levels of systolic blood pressure in such a test were associated with the development of micro‐ and macroalbuminuria.

• albuminuria
• blood pressure
• diabetic nephropathy
• exercise test
• prognosis