# A longitudinal analysis of population-level lipid and apolipoprotein trends over two decades: descriptive assessment using patient medians in a Swedish tertiary care center

## TL;DR

This study tracks changes in lipid and apolipoprotein levels over 19 years in Sweden, showing declining LDL-C and stable HDL-C, suggesting improved cardiovascular health trends.

## Contribution

The study provides a novel descriptive analysis of population-level lipid trends using patient medians over nearly two decades in a clinical setting.

## Key findings

- Median LDL-C levels declined from 3.18 to 2.62 mmol/L over 19 years, indicating improved lipid management.
- ApoA1 levels were notably higher in women compared to men, while ApoB levels were similar between sexes.
- Seasonal variation was negligible across all lipid and apolipoprotein analytes.

## Abstract

Cardiovascular disease (CVD) remains the leading cause of mortality worldwide. Lipid biomarkers, including direct low-density lipoprotein cholesterol (LDL-C), high-density lipoprotein cholesterol (HDL-C), apolipoprotein B (ApoB), and apolipoprotein A1 (ApoA1), are essential tools for cardiovascular risk assessment. Monitoring patient-derived median values over time may provide insights into population health and analytical performance. This study provides a descriptive analysis of population-level lipid results spanning nearly two decades. While trends in patient medians may support quality assurance, these data do not constitute a validated approach to risk prediction or definitive analytical monitoring due to the absence of outcome and treatment information.

We retrospectively analyzed routine clinical laboratory data from Uppsala University Hospital, Sweden, covering January 2006–December 2024. A total of 890,948 LDL-C, 867,446 HDL-C, 64,787 ApoB, and 65,500 ApoA1 results were included. Measurements were performed on Abbott Architect systems until 2021, after which assays were transferred to Roche Cobas Pro platforms. Statistical analyses included trend evaluation, variability assessment, and seasonal pattern analysis.

Women had modestly higher LDL-C and HDL-C levels compared to men, while ApoB values were similar between sexes. ApoA1 was notably higher in women. Over the 19-year period, median LDL-C declined from 3.18 to 2.62 mmol/L, consistent with improved lipid management. HDL-C remained stable (1.36–1.45 mmol/L), while ApoB and ApoA1 concentrations showed minimal change. Variability was highest for LDL-C (median CV 6.4%) and lowest for ApoA1 (median CV 2.6%). Seasonal variation was negligible across all analytes. Testing volumes increased substantially for LDL-C and HDL-C, whereas ApoB and ApoA1 requests peaked around 2010 and later declined.

Long-term monitoring of median patient values demonstrates declining LDL-C, stable HDL-C, and consistent ApoB/ApoA1 ratios with minimal seasonal effects. These findings highlight the potential utility of patient medians as supplementary quality indicators and for population-level lipid surveillance.