Diabetic cystopathy--a risk factor in diabetic nephropathy?

Twenty-seven patients with Type I diabetes and diabetic nephropathy were repeatedly tested (mean, 6 times per patient) for residual urine volumes with a noninvasive technique. Results in 43 of 162 investigations (27%) were abnormal, with residual volumes of greater than 15 ml. Twelve of 162 (7%) showed a residual volume greater than 100 ml. In any individual patient the occurrence of residual volumes was not a consistent finding, and the volumes varied. Pathologic residual volumes were more common in men, but all those with bacteriuria were women. All patients with residual volumes (N = 16) were given voiding instructions. There was no increase in residual volumes during the observation period (mean, 32 months), the median residual volume being 8 ml at the first observation and 5 ml at the last observation. The occurrence of residual urine could not be shown to correlate with progression of renal insufficiency. It is suggested that all patients with long-standing Type I diabetes should be tested by a noninvasive technique for residual urine volume and given voiding instructions to avoid acute retention episodes and complete atony of the bladder.