Role of combined serum homocysteine and small dense LDL-C in predicting cardiovascular events in obesity: a retrospective clinical study

To evaluate serum homocysteine (Hcy) and small dense low-density lipoprotein cholesterol (sdLDL-C) as predictors of cardiovascular risk in obese patients and their incremental value for prediction models. A retrospective cohort study was conducted on obese patients. Baseline data and laboratory parameters, including Hcy, sdLDL-C, and traditional cardiovascular risk factors, were collected. Cardiovascular events were recorded during follow-up. Multivariable logistic regression was used to assess the independent associations of Hcy and sdLDL-C with cardiovascular risk. Model performance was assessed using receiver operating characteristic (ROC) curves, calibration plots, and decision curve analysis (DCA). Cardiovascular events were strongly associated with elevated Hcy and sdLDL-C. Hcy levels showed a dose-response relationship with event rates. After adjustment for age, sex, body mass index, smoking status, hypertension, diabetes, conventional lipid profiles, high-sensitivity C-reactive protein, and estimated glomerular filtration rate, serum homocysteine (Hcy) remained independently associated with cardiovascular risk (OR = 1.90, 95% CI: 1.54–2.35, P < 0.001). sdLDL-C also showed significant predictive value (OR = 1.21, 95% CI: 1.13–1.30, P < 0.001). The traditional model’s area under the ROC curve (AUC) was 0.849. Adding Hcy or sdLDL-C individually improved discrimination, while the combined model achieved a significantly higher AUC of 0.972 (95% CI: 0.953–0.991), with superior calibration and clinical net benefit. In obese patients, Hcy and sdLDL-C are independent risk markers for cardiovascular events. Their combined use significantly enhances risk prediction model performance, aiding refined risk stratification.