LAUSR

Background The nutritional rehabilitation of malnourished patients hospitalised with anorexia nervosa is essential. The provision of adequate nutrition must occur, while simultaneously, minimising the risk of refeeding complications, such as electrolyte, metabolic, and organ dysfunction. The aim of this study was to compare the efficacy and safety of an iso-caloric lower carbohydrate/high fat enteral formula (28% carbohydrate, 56% fat) against a standard enteral formula (54% carbohydrate, 29% fat). Methods Patients (aged 15–25 years) hospitalised with anorexia nervosa were recruited into this double blinded randomised controlled trial. An interim analysis was completed at midpoint, when 24 participants, mean age 17.5 years (± 1.1), had been randomly allocated to lower carbohydrate/high fat (n = 14) or standard (n = 10) feeds. Results At baseline, there was no significant difference in degree of malnutrition, medical instability, history of purging or serum phosphate levels between the two treatment arms. A significantly lower rate of hypophosphatemia developed in patients who received the lower carbohydrate/high fat formula compared to standard formula (5/14 vs 9/10, p  = 0.013). The serum phosphate level decreased in both feeds, however it decreased to a larger extent in the standard feed compared to the lower carbohydrate/high fat feed (standard feed 1.11 ± 0.13 mmol/L at baseline vs 0.88 ± 0.12 mmol/L at week 1; lower carbohydrate/high fat feed 1.18 ± 0.19 mmol/L at baseline vs 1.06 ± 0.15 mmol/L at week 1). Overall, serum phosphate levels were significantly higher in the lower carbohydrate/high fat feed compared with standard feed treatment arm at Week 1 (1.06 ± 0.15 mmol/L vs 0.88 ± 0.12 mmol/L, p  < 0.001). There was no significant difference in weight gain, number of days to reach medical stability, incidence of hypoglycaemia, or hospital length of stay. Conclusions The results of this study indicate that enteral nutrition provided to hospitalised malnourished young people with anorexia nervosa using a lower carbohydrate/high fat formula (28% carbohydrate, 56% fat) seems to provide protection from hypophosphatemia in the first week compared to when using a standard enteral formula. Further research may be required to confirm this finding in other malnourished populations. Trial Registration : ANZCTR, ACTRN12617000342314. Registered 3 March 2017, http://anzctr.org.au/Trial/Registration/TrialReview.aspx?ACTRN=12617000342314 Patients hospitalised with anorexia nervosa require nutrition support as part of their treatment, whilst refeeding complications are prevented. Of particular concern, is the reintroduction of carbohydrate to malnourished patients, which has been proposed to cause a surge in insulin levels and disturbance in electrolytes, particularly a decrease in blood phosphate levels. This double-blinded randomised controlled trial measured the occurrence of low phosphate blood levels and other refeeding complications, in adolescent and young adult patients hospitalised with anorexia nervosa. These patients were provided either a lower carbohydrate/high fat feed (28% carbohydrate, 56% fat) or a standard enteral feed (54% carbohydrate, 29% fat). Fewer patients in the lower carbohydrate/high fat feed group (5/14) than standard feed group (9/10) developed a low phosphate level. There was no significant difference in weight gain, number of days to reach medical stability, occurrence of hypoglycaemia, or hospital length of stay.