Body surface area formulae: an alarming ambiguity

Abstract

Body surface area (BSA) plays a key role in several medical fields, including cancer chemotherapy, transplantology, burn treatment and toxicology. BSA is often a major factor in the determination of the course of treatment and drug dosage. A series of formulae to simplify the process have been developed. Because easy-to-identify, yet general, body coefficient results of those formulae vary considerably, the question arises as to whether the choice of a particular formula is valid and safe for patients. Here we show that discrepancies between most of the known BSA formulae can reach 0.5 m2 for the standard adult physique. Although many previous studies have demonstrated that certain BSA formulae provide an almost exact fit with the patients examined, all of these studies have been performed on a limited and isolated group of people. Our analysis presents a broader perspective, considering 25 BSA formulae. The analysis revealed that the choice of a particular formula is a difficult task. Differences among calculations made by the formulae are so great that, in certain cases, they may considerably affect patients’ mortality, especially for people with an abnormal physique or for children.

Comparison of methods to estimate glomerular filtration rate in paediatric oncology patients

“…14,16 Many of the equations identified in this study reported eGFR values normalised to a BSA of 1.73 m 2 (mL/min/1.73 m 2 ). Normalisation of eGFR to BSA has been criticised previously for different reasons: poor correlation between BSA and mGFR (mL/min), 36 inaccuracy of formulas to calculate BSA 37 and an overestimation of mGFR in paediatric patients, especially in malnourished patients. 38,39 In patients with a BSA <1.60 m 2 , normalised eGFR (mL/min/1.73 m 2 ) overestimated mGFR with a bias of 11.5%.…”

High‐Resolution Three‐Dimensional Photonic Scan‐Derived Equations Improve Body Surface Area Prediction in Diverse Populations

“…The complexity of newly developed equations is often cited as a barrier to their adoption, and clinicians have opted for simplified equations at the expense of precision . Patient safety should be of utmost concern, and the precision of BSA estimates may have treatment consequences . Using the most extreme cases shown in Table , if the measured BSA is 3.318 m 2 (Example 1), and drug X is dosed at 50 mg/m 2 , the patient should receive 165.9 mg. BSA estimates by the six equations under comparison range from 2.987 to 3.895 m 2 , indicating patient dosing with 149.4 to 194.8 mg. Consequently, the dose calculated would underprescribe by 10% based on the Nwoye and Al‐Shehri equation and overprescribe by 16% using the Jones equation.…”

“…The complexity of newly developed equations is often cited as a barrier to their adoption, and clinicians have opted for simplified equations at the expense of precision (37,38). Patient safety should be of utmost concern, and the precision of BSA estimates may have treatment consequences (9,13). Using the most extreme cases shown in 17%.…”

Standard medical nutrition therapy of 25 kcal/kg ideal bodyweight/day often does not reach even resting energy expenditure for patients with type 2 diabetes

“…Although BSA is easily calculated with height and bodyweight, and plays a key role in several medical fields, including cancer chemotherapy or transplantology, little notice is taken of BSA in MNT for diabetes patients. This is partly explained by the individual variation in BSA. Gibson et al .…”