Objective: This observational study: (a) compared serum creatinine (estimated glomerular filtration rate (EGFR)) to renal isotope 99mTc-DTPA (GFR) determined glomerular filtration rate, and evaluated whether either method (b) better determined the state of renal function, and (c) predict urinary tract infection (UTI), renal and urological structural lesions or mortality in veterans with traumatic spinal cord injury (SCI) and neurogenic bladder (NGB).
Design: Observational study.
Setting: VA Medical Center affiliated with Oklahoma University.
Participants: Veterans with SCI and regularly followed in SCI clinic. Demographic and clinical data, as well as, EGFR, GFR, blood urea nitrogen (BUN) and serum creatinine levels, and presence of UTI, renal and urinary bladder lesions on renal nuclear scan, renal ultrasound, and cystoscopy studies were recorded.
Interventions: None.
Main outcome measures: Urological lesions, UTI, and Mortality.
Results: For 161 patients with SCI and NGB the mean ± SD for EGFR was 104 ± 36 and 84 ± 32 for GFR. EGFR and GFR were positively correlated (r = 0.34, P = 0.015). GFR was significantly (P < 0.05) more sensitive and specific in determining renal functional state. Neither measures were significant indicator for UTI, renal or urological lesions; GFR was a significant predictor of risk of death (1.2 times increase in risk per 10 unit drop in GFR) even after adjusting for age (P = 0.040).
Conclusion: While GFR and EGFR are comparable measures of glomerular filtration, GFR was a more informative measure of renal functional state and risk of mortality than EGFR. Neither method predicted the presence of UTI related renal or urological lesions.
Keywords: Glomerular filtration rate; Observation; Renal isotope scan; Serum creatinine; Urinary tract infection.