title: Prospective Intervention of a Novel Levothyroxine Dosing Protocol Based on Body Mass Index after Thyroidectomy.
abstract: BACKGROUND
  Weight-based postoperative levothyroxine (LT4) dosing often fails to appropriately dose overweight and underweight patients. Previously, we created an LT4-dosing algorithm based on BMI. We hypothesize that more patients will achieve euthyroidism at their postoperative visit with the use of the protocol.
  
  
  METHODS
  A prospective evaluation was performed of our previously published BMI-based LT4 dosing. All adults who underwent thyroidectomy for benign disease between January 1, 2011 and December 31, 2013 were included; the new protocol was implemented in October 2012. Serum TSH was measured for all patients 6 to 8 weeks postoperatively, and adjustments were based on TSH.
  
  
  RESULTS
  Three hundred and thirty patients were included, with 54% undergoing thyroidectomy after institution of the protocol. The groups were well matched. Before protocol implementation, LT4 was dosed solely by weight and 25% of patients were euthyroid at initial follow-up. After the protocol, 39% of patients were euthyroid (p = 0.01). The percentage of patients who were given too high a dose of LT4 remained the same (46% vs 42%), and there was a significant reduction in the number of patients who were given too little (29% vs 19%; p = 0.05). The effect was most profound in patients with low and normal BMI, and there were slight differences between sexes.
  
  
  CONCLUSIONS
  Although correct initial dosing of LT4 remains challenging, this dosing protocol that we developed and implemented has improved patient care by increasing the number of patients who achieve euthyroidism at the first postoperative visit. We have made a change to our original protocol to incorporate sex differences into the calculation.
authors.affiliation: University of California, Irvine School of Medicine, Irvine, CA. Electronic address: delfenbe@uci.edu.
authors.forename: Dawn M
authors.initials: DM
authors.lastname: Elfenbein
authors.affiliation: Division of General Surgery, Department of Surgery, Section of Endocrine Surgery, University of Wisconsin School of Medicine and Public Health, Madison, WI.
authors.forename: Sarah
authors.initials: S
authors.lastname: Schaefer
authors.affiliation: Division of General Surgery, Department of Surgery, Section of Endocrine Surgery, University of Wisconsin School of Medicine and Public Health, Madison, WI.
authors.forename: Cynthia
authors.initials: C
authors.lastname: Shumway
authors.affiliation: University of Alabama, Birmingham, AL.
authors.forename: Herbert
authors.initials: H
authors.lastname: Chen
authors.affiliation: Division of General Surgery, Department of Surgery, Section of Endocrine Surgery, University of Wisconsin School of Medicine and Public Health, Madison, WI.
authors.forename: Rebecca S
authors.initials: RS
authors.lastname: Sippel
authors.affiliation: Division of General Surgery, Department of Surgery, Section of Endocrine Surgery, University of Wisconsin School of Medicine and Public Health, Madison, WI.
authors.forename: David F
authors.initials: DF
authors.lastname: Schneider
mesh_terms: D000328:Adult; D000368:Aged; D000465:Algorithms; D015992:Body Mass Index; D000066491:Clinical Decision-Making; D003661:Decision Support Techniques; D004334:Drug Administration Schedule; D005260:Female; D005500:Follow-Up Studies; D020249:Hormone Replacement Therapy / Q000379:methods*; D006801:Humans; D006980:Hyperthyroidism / Q000209:etiology / Q000517:prevention & control*; D007037:Hypothyroidism / Q000209:etiology / Q000517:prevention & control*; D008297:Male; D008875:Middle Aged; D011183:Postoperative Complications / Q000517:prevention & control*; D011446:Prospective Studies; D013965:Thyroidectomy; D013974:Thyroxine / Q000008:administration & dosage* / Q000627:therapeutic use; D016896:Treatment Outcome
chemical_list: D013974:Thyroxine