Creatinine clearance prediction in spinal cord injury patients: comparison of 6 prediction equations

The renal function of spinal cord injury patients frequently is overestimated by 3 commonly used equations to predict creatinine clearance. Overestimation of creatinine clearance may result in aminoglycoside overdosage and resultant nephrotoxicity. Three newer prediction equations have been developed from creatinine clearances measured in neurologically abnormal patients. These 6 equations were tested in 77 male and 9 female spinal cord injury patients (48 quadriplegics and 38 paraplegics, including 38 with acute and 48 with chronic injuries). The equation developed by Sawyer and Hutchins was superior to 2 other equations developed in spinal cord injury patients and 3 equations developed in neurologically normal patients. However, creatinine clearances predicted by this equation were within 30 ml. per minute of measured creatinine clearances in only two-thirds of the spinal cord injury patients. Errors ranged from overestimation by 95 ml. per minute (151 per cent) to underestimation by 106 ml. per minute (45 per cent). The potential for large errors in creatinine clearance prediction necessitates measurement of creatinine clearance as soon as possible when renal excreted and toxic pharmaceuticals are administered to spinal cord injury patients.