title: The impact of different algorithms for ideal body weight on screening for hydroxychloroquine retinopathy in women.
abstract: OBJECTIVE
  To determine how algorithms for ideal body weight (IBW) affect hydroxychloroquine dosing in women.
  
  
  METHODS
  This was a retrospective study of 520 patients screened for hydroxychloroquine retinopathy. Charts were reviewed for sex, height, weight, and daily dose. The outcome measures were ranges of IBW across algorithms; rates of potentially toxic dosing; height thresholds below which 400 mg/d dosing is potentially toxic; and rates for which actual body weight (ABW) was less than IBW.
  
  
  RESULTS
  Women made up 474 (91%) of the patients. The IBWs for a height varied from 30-34 pounds (13.6-15.5 kg) across algorithms. The threshold heights below which toxic dosing occurred varied from 62-70 inches (157.5-177.8 cm). Different algorithms placed 16%-98% of women in the toxic dosing range. The proportion for whom dosing should have been based on ABW rather than IBW ranged from 5%-31% across algorithms.
  
  
  CONCLUSIONS
  Although hydroxychloroquine dosing should be based on the lesser of ABW and IBW, there is no consensus about the definition of IBW. The Michaelides algorithm is associated with the most frequent need to adjust dosing; the Metropolitan Life Insurance, large frame, mean value table with the least frequent need. No evidence indicates that one algorithm is superior to others.
authors.affiliation: Charlotte Eye, Ear, Nose and Throat Associates, Charlotte, North Carolina, NC, USA.
authors.forename: David J
authors.initials: DJ
authors.lastname: Browning
authors.affiliation: Charlotte Eye, Ear, Nose and Throat Associates, Charlotte, North Carolina, NC, USA.
authors.forename: Chong
authors.initials: C
authors.lastname: Lee
authors.affiliation: Charlotte Eye, Ear, Nose and Throat Associates, Charlotte, North Carolina, NC, USA.
authors.forename: David
authors.initials: D
authors.lastname: Rotberg
keywords: actual body weight; algorithms; hydroxychloroquine; ideal body weight; retinopathy; toxicity
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