Urinary tract stone development in patients with myelodysplasia subjected to augmentation cystoplasty

Patients with myelodysplasia who have undergone augmentation cystoplasty are at risk for urinary tract stones. We sought to determine the incidence and risk factors for stone development in this population. The charts of 40 patients with myelodysplasia who have undergone augmentation cystoplasty were reviewed. None had a prior history of urinary tract stones. All patients were seen on an annual basis with plain abdominal imaging, renal ultrasonography, and laboratory testing. Statistical analysis included a multivariable bootstrap resampling method and Student's t-test. Fifteen (37.5%) patients developed stones, 14 with bladder stones and 1 with a solitary renal stone, at a mean of 26.9 months after augmentation. Five (33.3%) developed recurrent bladder stones. The patient with a renal stone never developed a bladder stone. The mean follow-up for the stone formers was 117.2 months and for non-stone formers was 89.9 months. The stone incidence per year was 6.8%. Risk factors included a decline in serum chloride after augmentation (P = .02), female sex, younger age at time of augmentation, longer time period since augmentation, and bowel continence. A significant proportion of patients with myelodysplasia subjected to augmentation cystoplasty develop urinary tract stones, predominantly in the bladder. Dehydration may play a role in development of lower urinary tract stones as the decline in serum chloride suggests contraction alkalosis, which could lead to constipation and improved bowel continence. Therefore, improved hydration should be a goal in this cohort.