OBJECTIVES: To determine (1) the variability of annual creatinine clearance (C(Cr)) testing for subjects with chronic spinal cord injury (SCI) and (2) whether decisions to change neurogenic bladder management are made based on C(Cr) measurements. DESIGN: Retrospective chart review. SETTING: Inpatient Veterans Affairs SCI unit. PARTICIPANTS: The medical records of 70 men were consecutively selected for review from among 664 veterans enrolled in the SCI clinic. All patient charts had to have at least 5 C(Cr) tests performed within 10 years preceding the review. INTERVENTIONS: Not applicable. MAIN OUTCOME MEASURES: Development of renal insufficiency and change in medical or bladder management of the patient, based on the results of the C(Cr) test. RESULTS: For individual patients, the results of 24-hour C(Cr) were highly variable from 1 evaluation to the next; the within-subject standard deviation (SD) for C(Cr) was 25.9mL/min. The within-subject SD for serum creatinine was 0.12mg/dL. For all comparisons of repeatability, variability, and reliability, serum creatinine was superior to C(Cr). No medical management decisions were made based on the result of the 24-hour creatinine clearance. Renal ultrasound results and postvoid bladder residuals were the major factors in changing medical management with regard to renal function preservation. CONCLUSIONS: The C(Cr) test has little value as a screening measure for renal disease in SCI patients because of its variability in serial testing.
OBJECTIVES: To determine (1) the variability of annual creatinine clearance (C(Cr)) testing for subjects with chronic spinal cord injury (SCI) and (2) whether decisions to change neurogenic bladder management are made based on C(Cr) measurements. DESIGN: Retrospective chart review. SETTING: Inpatient Veterans Affairs SCI unit. PARTICIPANTS: The medical records of 70 men were consecutively selected for review from among 664 veterans enrolled in the SCI clinic. All patient charts had to have at least 5 C(Cr) tests performed within 10 years preceding the review. INTERVENTIONS: Not applicable. MAIN OUTCOME MEASURES: Development of renal insufficiency and change in medical or bladder management of the patient, based on the results of the C(Cr) test. RESULTS: For individual patients, the results of 24-hour C(Cr) were highly variable from 1 evaluation to the next; the within-subject standard deviation (SD) for C(Cr) was 25.9mL/min. The within-subject SD for serum creatinine was 0.12mg/dL. For all comparisons of repeatability, variability, and reliability, serum creatinine was superior to C(Cr). No medical management decisions were made based on the result of the 24-hour creatinine clearance. Renal ultrasound results and postvoid bladder residuals were the major factors in changing medical management with regard to renal function preservation. CONCLUSIONS: The C(Cr) test has little value as a screening measure for renal disease in SCI patients because of its variability in serial testing.