Influences on renal function in chronic spinal cord injured patients

Purpose: The optimal method of bladder management in the spinal cord injure d population remains controversial. We determined the significance of bladd er management and other factors on renal function in this population. Materials and Methods: We retrospectively reviewed the medical records and upper tract imaging studies of 308 patients with a mean followup of 18.7 ye ars since injury. Renal function was assessed by serum creatinine, creatini ne clearance and proteinuria measurement, and by upper tract abnormalities on renal ultrasound and nuclear medicine renal scan. Independent variables evaluated for an influence on renal function included patient age, interval since injury, injury level and completeness, vesicoureteral reflux, histor y of diabetes mellitus and bladder management method. Results: Mean serum creatinine plus or minus standard deviation in patients on chronic Foley catheterization, clean intermittent catheterization and s pontaneous voiding was 1.08 +/- 0.99, 0.84 +/- 0.23 and 0.97 +/- 0.45 mg./d l. (analysis of variance p = 0.05, Student's t test p = 0.10), and mean cre atinine clearance was 91.1 +/- 46.5, 113.4 +/- 39.8 and 115 +/- 49 ml. per minute, respectively (analysis of variance and Student's t test p <0.01), r espectively. Proteinuria was present in 19 patients (6.2%) in the Foley cat heterization, 3 (1%) in the clean intermittent catheterization and 4 (1.3%) in the spontaneous voiding group (chi-square test p <0.01), while there we re upper tract abnormalities in 56 (18.2%), 20 (6.5%) and 24 (7.8%) patient s, respectively (chi-square test p <0.01). Multiple regression analyses rev ealed no significant predictors of serum creatinine, although older patient age and Foley catheterization significantly predicted low creatinine clear ance. Additional logistic regression analyses showed that Foley catheteriza tion was associated with proteinuria and vesicoureteral reflux was associat ed with upper tract abnormalities. Conclusions: While renal function may be preserved by all forms of bladder management, chronic indwelling catheters may contribute to renal deteriorat ion.