Lipoprotein(a) as a cardiovascular risk factor among patients with and without diabetes Mellitus: the Mass General Brigham Lp(a) Registry

Abstract Background Diabetes mellitus (DM) and Lp(a) are well-established predictors of coronary artery disease (CAD) outcomes. However, their combined association remains poorly understood. Objective To investigate the relationship between elevated Lp(a) and DM with CAD outcomes. Methods Retrospective analysis of the MGB Lp(a) Registry involving patients ≥ 18 years who underwent Lp(a) measurements between 2000 and 2019. Exclusion criteria were severe kidney dysfunction, malignant neoplasms, and prior atherosclerotic cardiovascular disease (ASCVD). The primary outcome was a combination of cardiovascular death or myocardial infarction (MI). Elevated Lp(a) was defined as > 90th percentile (≥ 216 nmol/L). Results Among 6,238 patients who met the eligibility criteria, the median age was 54, 45% were women, and 12% had DM. Patients with DM were older, more frequently male, and had a higher prevalence of additional cardiovascular risk factors. Over a median follow-up of 12.9 years, patients with either DM or elevated Lp(a) experienced higher rates of the primary outcome. Notably, those with elevated Lp(a) had a higher incidence of the primary outcome regardless of their DM status. The annual event rates were as follows: No-DM and Lp(a) < 90th% − 0.6%; No-DM and Lp(a) > 90th% − 1.3%; DM and Lp(a) < 90th% − 1.9%; DM and Lp(a) > 90th% − 4.7% ( p < 0.001). After adjusting for confounders, elevated Lp(a) remained independently associated with the primary outcome among both patients with DM (HR = 2.66 [95%CI: 1.55–4.58], p < 0.001) and those without DM (HR = 2.01 [95%CI: 1.48–2.74], p < 0.001). Conclusions Elevated Lp(a) constitutes an independent and incremental risk factor for CAD outcomes in patients with and without DM.