Clinical and Metabolic Efficacy of Glutamine- Supplemented Parenteral Nutrition After Bone Marrow Transplantation. A Randomized,Double-Blind,Controlled Study

Glutamine (GLN), long considered to be a nonessential amino acid, may be conditionally essential during periods of metabolic stress.¹ It has been suggested that the improved results seen in patients given enteral, as opposed to parenteral, nutrition may in part be due to the provision of GLN. Commercial amino acid solutions do not contain GLN because of its inherent instability. Glutamine-supplemented solutions are currently under investigation and may be of benefit to patients who cannot tolerate enteral feedings. Bone marrow transplantation is one such setting, where the combination of radiation and chemotherapy make enteral support untenable.

Forty-five patients underwent allogeneic bone marrow transplantation for hematologic malignancies. They were randomly assigned to receive either a standard glutamine-free total parenteral nutrition solution or one supplemented with L-glutamine to provide 0.57 g of GLN/ kg per day in a blinded fashion. Overall protein intake was 1.5 g/kg per day. Patients were allowed to eat ad libitum, but they consumed fewer than 300 calories daily. Total parenteral nutrition was discontinued when patients were able to consume 50% of their needs orally daily for 3 consecutive days.

All patients survived their acute hospitalization. One hundred-day survival was not different between the two groups. The GLN group had significantly fewer clinical infections than did the control group. Ten of 24 GLN patients completed their hospitalization with no positive cultures as opposed to 1 of 21 control patients (p < .01). The majority of positive cultures in the control group were for Candida albicans.

Daily nitrogen balance data were available in those patients not being treated with corticosteroids for graftvs-host disease. During the early phase of transplantation (days 4 to 11), average daily nitrogen balance remained more negative in the control group (—4.2 ± 1.2 vs -1.4 ± 0.5 g; p < .002). There was no statistically significant difference between the two groups from days 18 to 25.

Total days of parenteral support were equal in both groups. However, total hospital days were significantly fewer in the GLN group, most likely because of the decreased incidence of septic complications.