Comparative Study of Calculated LDL-Cholesterol Levels with the Direct Assay in Patients with Hypothyroidism

Area of Science:

• Endocrinology
• Clinical Biochemistry
• Cardiovascular Medicine

Background:

• Hypothyroidism is a known risk factor for coronary artery disease.
• Accurate measurement of low-density lipoprotein-cholesterol (LDL-C) is crucial for cardiovascular risk assessment.
• Hypothyroidism can affect lipid profiles, potentially impacting the accuracy of calculated LDL-C.

Purpose of the Study:

• To compare the accuracy of 13 different formulas for calculating LDL-C in hypothyroid patients.
• To evaluate the performance of the newly derived Martin's formula against established methods.
• To identify the most reliable and least biased formula for LDL-C estimation in this population.

Main Methods:

• An analytical cross-sectional study involving 105 laboratory-confirmed hypothyroid patients.
• Lipid profile analysis was performed on blood samples.
• Calculated LDL-C values from 13 different formulas were compared with direct LDL-C assay results.

Main Results:

• Friedewald's, Cordova's, Anandaraja's, Hattori's, and Chen's formulas demonstrated a bias within ±5% of direct LDL-C.
• Anandaraja's formula exhibited the lowest absolute bias (2.744), while Cordova's formula showed the lowest bias percentage (-1.077).
• The recently proposed Martin's formula showed a higher bias compared to Friedewald's and Anandaraja's formulas.

Conclusions:

• This study is the first to compare multiple LDL-C calculation formulas specifically in hypothyroid patients.
• Anandaraja's formula is as effective as Friedewald's formula and serves as a reliable, cost-effective alternative for LDL-C evaluation in hypothyroid individuals.
• The Martin's formula requires further validation in hypothyroid populations due to observed higher bias.