Lipoprotein(a) as a Higher Residual Risk for Coronary Artery Disease in Patients with Type 2 Diabetes Mellitus than without

PURPOSE: Lipoprotein(a) (Lp[a]) is well-known as a residual risk factor for coronary artery disease (CAD). However, the different adverse effects of Lp(a) about CAD in patients with or without type 2 diabetes mellitus (T2DM) are unclear. This study aimed to investigate the Lp(a) thresholds for CAD diagnosis in T2DM and non-T2DM patients, and further compare the Lp(a) alarm values along with optimal low-density lipoprotein cholesterol (LDL-C) level. METHODS: This retrospective study consecutively enrolled patients with suspected CAD who underwent coronary angiography in Guangdong Provincial People’s Hospital between September 2014 and July 2015. A logistic regression model was established to explore the association of Lp(a) and CAD in patients. Restricted cubic splines were used to compare the threshold values of Lp(a) for CAD in patients with and without T2DM, and further in optimal LDL-C level situation. RESULTS: There were 1522 patients enrolled finally. After multivariable adjustment, Lp(a) was an independent risk factor for CAD in patients with T2DM (odds ratio [OR]: 1.98, 95% CI]: 1.12–3.49, p = 0.019) and without T2DM (OR: 3.42, 95% CI: 2.36–4.95, p < 0.001). In the whole population, the Lp(a) threshold of CAD was 155, while 145 mg/L for T2DM and 162 mg/L for non-T2DM ones, respectively. In patients with LDL-C<1.8 mmol/l, the alarm value of Lp(a) was even lower in T2DM than non-T2DM patients (155 vs 174 mg/L). CONCLUSION: Lp(a) was a significant residual risk for CAD in patients whether with T2DM or not. And Lp(a) had a lower alarm value in T2DM patients, especially in optimal LDL-C level.