A paper which causes me significant concern.
This is my blog which explains, I hope, my deep scepticism about existing prediction of required levothyroxine doses.
helvella - Estimation of Levothyroxine Dosing in Adults
A discussion about the use of formulas to estimate levothyroxine dosing. Includes link to a downloadable spreadsheet which calculates several of these.
helvella.blogspot.com/p/hel...
But at least the existing approaches have an understandable formula. And, despite me producing a spreadsheet, there is nothing that cannot easily be worked out with at most a calculator, pen and paper.
Maybe it is simply because the publisher has erected a paywall, but we do not have access to the formulas behind this approach. We cannot even start to examine the computer-assisted dose selection. Nor the formulas. Nor the documentation surrounding it. Nor the theoretical basis.
That its goal is defined in terms of TSH is clearly not supported by much theory and many papers.
Their choice of factors is questionable.
Their approach to validation needs to be justified. If even one patient receives a worse outcome by following their algorithm, that patient ends up in a difficult position. Could they demand some form of compensation? And were they fully informed before allowing their health to be controlled by an obscure algorithm?
I am reminded of some of the issues with Body Mass Index. BMI is often quoted in terms of weight and height. But it needs far more thought than that. Applying basic BMI calculations to a one-legged person immediately shows up its naivety.
Computer-Assisted Levothyroxine Dose Selection for the Treatment of Postoperative Hypothyroidism
Martin Barrio, Christopher D. Raeburn, Robert McIntyre, Jr., Maria Albuja-Cruz, Bryan R. Haugen, and Nikita Pozdeyev
Published Online: 20 Apr 2023 doi.org/10.1089/thy.2023.0033
Abstract
Background: Thyroid hormone replacement with levothyroxine (LT4) is a recommended treatment for patients undergoing thyroidectomy. The starting LT4 dose is frequently calculated based on the patient's weight. However, the weight-based LT4 dosing performs poorly in clinical practice, with only ∼30% of patients achieving target thyrotropin (TSH) levels at the first thyroid function testing after treatment initiation. A better way to calculate the LT4 dose for patients with postoperative hypothyroidism is needed.
Methods: In this retrospective cohort study we used demographic, clinical, and laboratory data for 951 patients after thyroidectomy and several regression and classification machine learning methods to develop an LT4 dose calculator for treating postoperative hypothyroidism targeting the desired TSH level. We compared the accuracy with the current standard-of-care practice and other published algorithms and evaluated generalizability with fivefold cross-validation and out-of-sample testing.
Results: The retrospective clinical chart review showed that only 285/951 (30%) patients met their postoperative TSH goal. Obese patients were overtreated with LT4. An ordinary least squares regression based on weight, height, age, sex, calcium supplementation, and height:sex interaction predicted prescribed LT4 dose in 43.5% of all patients and 45.3% of patients with normal postoperative TSH (0.45-4.5 mIU/L). The ordinal logistic regression, artificial neural networks regression/classification, and random forest methods achieved comparable performance. LT4 calculator recommended lower LT4 doses to obese patients.
Conclusions: The standard-of-care LT4 dosing does not achieve the target TSH in most thyroidectomy patients. Computer-assisted LT4 dose calculation performs better by considering multiple relevant patient characteristics and providing personalized and equitable care to patients with postoperative hypothyroidism. Prospective validation of LT4 calculator performance in patients with various TSH goals is needed.
Keywords: levothyroxine; machine learning; postoperative hypothyroidism.
