# Friedewald and Martin–Hopkins formulae for estimating low-density lipoprotein cholesterol in a Malagasy population

## TL;DR

This study compares two methods for estimating LDL cholesterol in Madagascar, finding that both are generally accurate but less so at higher triglyceride levels.

## Contribution

The study evaluates LDL-C estimation formulae in a Malagasy population, providing insights for resource-limited settings in Africa.

## Key findings

- Both Friedewald and Martin–Hopkins formulae showed strong correlation with direct LDL-C measurements.
- Friedewald had lower mean difference and better concordance than Martin–Hopkins.
- Accuracy of both formulae decreased with increasing triglyceride levels.

## Abstract

Low-density lipoprotein cholesterol (LDL-C) estimation is commonly used in Madagascar due to cost-effectiveness. However, genetic variability and formula limitations may affect accuracy.

To compare LDL-C estimated by the Friedewald and Martin–Hopkins formulae with directly measured LDL-C in a Malagasy population.

LDL-C values estimated using both formulae were compared with direct LDL-C in 346 samples from patients ≥ 18 years analysed in a biochemistry laboratory. Samples were divided into four groups based on triglyceride levels: < 1.13 mmol/L; 1.13 mmol/L – 1.69 mmol/L; 1.69 mmol/L – 2.26 mmol/L; ≥ 2.26 mmol/L.

Both formulae showed a strong, statistically significant correlation with direct LDL-C (r = 0.89). Mean comparison revealed overestimation by both formulae, more pronounced with Friedewald (mean difference 0.15 mmol/L) than Martin–Hopkins (0.21 mmol/L). Differences increased with rising triglyceride levels. Both formulae demonstrated good agreement with direct measurement, acceptable biases and similar limits, but Friedewald had a lower overall percentage error.

The Friedewald formula showed better correlation, higher concordance and lower mean difference than Martin–Hopkins. Both formulae showed limitations depending on triglyceride concentration.

This study evaluates Friedewald and Martin–Hopkins LDL-C estimation against direct measurement in a Malagasy population, highlighting their validity in Africa and implications for clinical decisions in resource-limited settings.