Kantonsspital St.Gallen
login

High Risk of Hypophosphatemia in Patients with Previous Bariatric Surgery Receiving Ferric Carboxymaltose: A Prospective Cohort Study

Manuela Schöb, Andrea Räss, Nicola Frei, Stefan Aczel, Michael Brändle & Stefan Bilz

abstract

BACKGROUND
Iron deficiency is a common finding in patients with previous bariatric surgery, and parenteral supplementation is frequently required. Ferric carboxymaltose (FCM) is among the preferred compounds used but may be associated with new-onset hypophosphatemia. This study was undertaken to study the prevalence of hypophosphatemia following FCM in patients with previous bariatric surgery, a population that may be at particular risk due to highly prevalent secondary hyperparathyroidism.

METHODS
Patients with previous bariatric surgery and iron depletion scheduled for FCM infusion were prospectively studied before and one week after FCM application. The primary endpoint was new-onset hypophosphatemia. Patients were followed until plasma phosphate had normalized without replacement.

RESULTS
Fifty-two patients (40 females) following Roux-en-Y gastric bypass (n = 50) or sleeve gastrectomy (n = 2), with a median age of 46 years (range 22-68) and a BMI of 32.2 kg/m (27.5-37.3), were analyzed. Fifteen patients (29%) developed new-onset hypophosphatemia, with 11 (21%) requiring oral phosphate supplementation for a median duration of 14 days (14-25). The plasma phosphate decreased by 0.3 mmol/l (-0.5--0.2; p < 0.001) secondary to a 56% increase in the fractional urinary phosphate excretion (p < 0.001). This was associated with a significant increase in serum intact FGF23 (+30%; p < 0.001) and a decrease in serum 1,25(OH)2 vitamin D3 concentrations (-37.6%; p < 0.001).

CONCLUSION
Patients with previous bariatric surgery receiving FCM are at considerable risk of developing significant hypophosphatemia secondary to increased renal phosphate wasting through a mechanism involving FGF23. Monitoring plasma phosphate should be considered following FCM in patients with previous bariatric surgery.

CLINICAL TRIAL REGISTRATION
ISRCTN registry, ISRCTN12291677, https://www.isrctn.com.
   
citation Schöb M, Räss A, Frei N, Aczel S, Brändle M, Bilz S. High Risk of Hypophosphatemia in Patients with Previous Bariatric Surgery Receiving Ferric Carboxymaltose: A Prospective Cohort Study. Obes Surg 2020;.
   
type journal paper/review (English)
date of publishing 27-03-2020
journal title Obes Surg
ISSN electronic 1708-0428
PubMed 32221822
DOI 10.1007/s11695-020-04544-x