Bladder stone incidence in persons with spinal cord injury: Determinants and trends, 1973-1996

Objectives. To examine the current trend in the incidence of an initial bla dder stone and the potential contributing factors among persons with spinal cord injury. Methods. A longitudinal cohort of 1336 patients with spinal cord injury who were injured between 1973 and 1996 and followed up on a yearly basis up to 1999 in a single institution was used to estimate bladder stone incidence. Multivariable analysis was performed to identify risk factors for an initi al bladder stone. Results. During the study period, 229 incident bladder stone cases were doc umented. It is estimated that for those injured in 1973 to 1979, 1980 to 19 84, 1985 to 1989, and 1990 to 1996, the 5-year cumulative incidence rate of an initial bladder stone was 29%, 23%, 14%, and 8%, respectively (P <0.000 1). This decreasing trend was consistent for various demographic and clinic al characteristics. During the first year after injury only, the bladder st one risk increased with decreasing age (P <0.0001) and was greater for whit es. A neurologically complete lesion was associated with an increased bladd er stone risk in later years (P = 0.008). Males and persons with indwelling and intermittent catheters had a higher risk during all the years after th e injury. Conclusions. With improvement in urologic rehabilitation, bladder stone inc idence has declined during the past several decades. The study results, how ever, suggest that new strategic interventions may be required to further p revent stone occurrence in individuals with spinal cord injury and a comple te neurologic lesion who are using indwelling catheterization, because thes e patients are still at a relatively higher risk. (C) 2001, Elsevier Scienc e Inc.