Background and aims The refeeding syndrome (RFS) is a potentially fatal condition characterised by fluid and electrolyte abnormalities, most notably hypophosphatemia. The purpose of this study was to determine the incidence of hypophosphatemia without prophylactic phosphate supplementation during refeeding in hospitalised adolescents with Anorexia Nervosa (AN).

Methods This study took place at the Division of Adolescent Medicine, Hacettepe University. Between January 2010 and April 2016, 32 adolescents with AN met criteria for admission. Nutritional rehabilitation was started and initial calories served depended on the type of AN (restrictive or binging-purging), the patient’s diet history and calorie intake before hospitalisation. If the patient was consuming calories less than 750kkcal/day, then 750kkcal divided into 3 meals was started. If the patient was consuming greater than 750kkcal, then 250kkcal was added to the consumption and depending on the calories divided into 3 main meals and 1–3 snacks. The daily calories were increased slowly according to weight gain. A weight gain criterion of maximum 1.0 kg/week was accepted safe to avoid RFS. Patients were followed closely and electrolytes were obtained daily for the first 5 days and longer if necessary.

Results The mean calorie consumed before admission was 693±557(min-max:0–3000) kkal. Mean calorie prescribed at admittance was 974±333 min-max:750–1750) kkal. Hypophosphatemia occurred in 2 patients during refeeding. The initial phosphate level was 3.74 mg/dl and 3.16 mg/dl and dropped to 2.5 mg/dl on day 2 with 1000kcal/day and 1.96 mg/dl on day 3 with 1250kcal, respectively. Replacement with oral neutral phosphate was given at 2 cc/kg for 3 days for both. There were no adverse events or clinical symptoms requiring any extra medical intervention.

Conclusions The debate concerning prophylactic phosphate to prevent RFS continues. While some authors advise daily phosphate supplementation to all patients during initial hospitalisation period, others recommend close early monitoring and supplementation only when phosphate levels begin to decline. Authors of protocols that opt to treat prophylactically have still closely monitor their patients for the first week which means patients will still have blood drawn daily.

In this study, the incidence of hypophosphatemia was found low without any phosphate supplementation. By monitoring phosphorus and supplementing as needed, we were able to avert the clinical manifestations of the RFS.