Serious renal impairment is associated with long-term parenteral nutrition

Thirty-three current long-term total parenteral nutrition (TPN) patients (13 men, 20 women) aged 21 to 79 years were prospectively studied to evaluate their change in glomerular filtration rate since beginning TPN. Creatinine clearance (CrCl) from the subject's initial home TPN clinic visit and at present were estimated from standard formulas and compared. The CrCl in 12 patients who had received home TPN for > 10 years was estimated retrospectively on a yearly basis. The estimated CrCl as an accurate measure of glomerular filtration rate was confirmed by measuring plasma indium-111 diethylenetriamine pentaacetic acid clearance. The mean daily intravenous protein intake and days during which nephrotoxic medications were used and number of bacteremic/fungemic episodes were determined for each subject. CrCl declined by 3.5 +/- 6.3% per year (p = .004). Twenty-nine of 33 patients had decreases of 0.6% to 15.4% per year. Tubular function, as determined by the tubular reabsorption of phosphate, was impaired in 52% of the subjects. The intravenous protein load averaged 1.28 +/- 0.32 g/kg per day, nephrotoxic drug use averaged 3.4 +/- 4.0% of all days on home TPN, and each patient averaged 2.3 episodes of bacteremia or fungemia since home TPN was started (0.5 +/- 0.5 episodes per year). When all factors were assessed simultaneously, nephrotoxic drug use, episodes of bacteremia/fungemia, and age accounted for approximately 46% of the variability in CrCl. When bacteremia/fungemia was expressed as a yearly rate, nephrotoxic drug use assumed no role in the glomerular filtration rate determination; infection rate and age alone accounted for 53% of the CrCl variability. We describe a profound decrease in renal function associated with long-term TPN, most of which is largely unexplained.