# Association between the non-high-density lipoprotein cholesterol to high-density lipoprotein cholesterol ratio and peripheral artery disease in vascular surgery inpatients aged 50 and above: a retrospective cross-sectional study

## TL;DR

This study found a nonlinear relationship between a cholesterol ratio and peripheral artery disease in older adults, with potential sex differences.

## Contribution

The study identifies a J-shaped association between non-HDL-C/HDL-C ratio and PAD, revealing a potential sex-specific threshold effect.

## Key findings

- The NHHR was nonlinearly associated with PAD, with a J-shaped relationship and a turning point around NHHR = 2.75.
- Patients in the third NHHR quartile had the lowest PAD risk after adjusting for confounders.

## Abstract

Peripheral artery disease (PAD) is a major manifestation of systemic atherosclerosis and affects vascular health in older adults. Dyslipidaemia contributes significantly to PAD, but the predictive value of composite lipid indices remains unclear. The non-high-density lipoprotein cholesterol (non-HDL-C) to high-density lipoprotein cholesterol (HDL-C) ratio (NHHR) reflects the balance between atherogenic and protective lipoproteins. This study aimed to explore the association between the NHHR and PAD among vascular surgery inpatients aged ≥50 years in Kunshan, China.

This retrospective cross-sectional study included 3,532 patients (aged ≥ 50 years) hospitalized at the Affiliated Kunshan Hospital of Jiangsu University, Suzhou, from December 2017 to August 2024. NHHR, calculated as (total cholesterol − HDL-C)/HDL-C, was the exposure variable; PAD, defined as PAD-like symptoms with an ankle brachial index < 0.9, was the outcome. Covariates included age, sex, lipoprotein(a) level [Lp(a)], apolipoprotein A1 level (Apo A1), alanine aminotransferase (ALT) level, neutrophil count (NEUT), hypertension status, diabetes status, smoking status, and alcohol consumption status. Multivariate logistic regression, smooth curve fitting, and threshold analyses were performed.

After adjustment for confounders, the NHHR was nonlinearly associated with PAD (OR = 0.77; 95% CI: 0.65–0.93; p = 0.006). Patients in the third NHHR quartile had the lowest PAD risk (OR = 0.51; 95% CI: 0.35–0.75; p < 0.001). Smooth curve fitting indicated a J-shaped relationship with a turning point around NHHR = 2.75. Below this threshold, a higher NHHR correlated with a lower PAD risk, whereas above it, the risk increased. A significant sex interaction was observed (P for interaction < 0.05).

The NHHR was associated with the presence of PAD, with the evidence suggesting a nonlinear relationship and potential sex-specific differences. Given the retrospective cross-sectional design, this association does not support causal inference or strong predictive claims. The NHHR may help identify individuals who could benefit from further clinical evaluation for PAD, but prospective studies are needed to confirm its clinical relevance before its routine application.