Current trend and risk factors for kidney stones in persons with spinal cord injury: a longitudinal study

Abstract

Study design: A multi-center longitudinal study. Objectives: To estimate the current trend in the incidence of ®rst kidney stone among persons with spinal cord injury (SCI) and to delineate the potential contributing factors. Setting: Twenty-one Model SCI Care Systems throughout the United States. Methods: A longitudinal cohort of 8314 subjects enrolled in the National SCI Database between 1986 and 1999 was used to estimate and compare the incidence of ®rst kidney stone with a previous report of 5850 SCI patients injured between 1973 and1982. A Cox regression analysis was performed to identify risk factors for stones, including age, race, gender, severity of injury, and method of urinary drainage. These variables have been routinely collected, on a yearly basis, by the collaborating SCI centers. Results: During the 12 years, 6 months of case ascertainment, 286 incident stone cases were documented. The risk was greatest during the ®rst 3 months after injury (31 cases per 1000 person-years), quickly decreasing and leveling o later (eight cases per 1000 person-years). It was estimated that within 10 years after injury, 7% of persons with SCI would develop their ®rst kidney stone. There was no evidence that the risk has changed over the past 25 years (P=0.96). During the ®rst year post injury only, a signi®cantly increased risk of stones was observed in Caucasians and persons aged 45 years or older. A positive association of the severity of injury and requiring instrumentation for bladder emptying with kidney stones was found after the ®rst year post injury. The type of urinary drainage, including indwelling, intermittent, and condom catheterization, had no signi®cant dierential eect on stone formation at either risk period. Conclusions: The highest risk of kidney stones is within the ®rst few months post injury. Little progress has been made in reducing this risk. Although inability to control bladder function is an important risk factor after the ®rst year post injury, for those who need bladder management, the type of urinary drainage does not appear to be an important factor in determining risk. Spinal Cord (2000) 38, 346 ± 353

Evidence-based management of upper tract urolithiasis in the spinal cord-injured patient

“…The risks of stone formation are highest in the first few months following the injury, cited as the initial 3 months in the Alabama study, 3 and 6 months in the Danish study. 5 This initial phase of stone formation is most likely due to early demineralisation of the bones of the lower limbs, leading to so called 'immobilisation hypercalciuria'.…”

“…[3][4][5] As with the general population, males have a somewhat higher risk of stone formation than females. 3 The two longitudinal studies of patients with SCI, based on a national database have suggested the incidence has remained static over the last 25 years, despite advances in bladder drainage, antibiotic use and upper tract imaging. 1,3 The reasons for this remain unclear.…”

“…In a study based on the United States SCI database, stone incidence increased with increasing temperature and decreasing latitude, suggesting geographic factors may also have a role in stone formation. 3 Recurrence rates for stone disease are also important in the SCI population. One case control study reports 72% of stone formers had a further upper tract stone within 2 years.…”

Ultrasound findings of the urinary tract in patients with spinal cord injury: a study of 1005 cases

“…The bladder management method has been reported to have no effect on renal calculi formation. 8,15 Bartel et al 5 noted bladder calculi by IUC in 6.6% and by CIC in 2%. Chen et al 14 found that IUC was associated with a substantially greater risk of bladder calculi; however, Ku et al 12 did not show this relationship with bladder calculi.…”

“…5,12 Chen et al 14,15 reported that the Table 4 Logistic regression analysis of the predictors of urinary tract abnormalities Ultrasound findings of the urinary tract in SCI Ü Güzelküçük et al risk for bladder and renal calculi reached its peak during the first 3 months after SCI and decreased after the first year. In the current study, it was observed that the highest occurence of bladder calculi was during the first year after SCI.…”