Lipoprotein(a) levels and risk of adverse events after myocardial infarction in patients with and without diabetes

Abstract

Abstract Background There is a positive continuous association between Lipoprotein(a) (Lp[a]) levels and the risk of recurrent ischemic events in patients with recent myocardial infarction (MI). However, the prognostic significance of the association between high Lp(a) levels and diabetes has been poorly investigated after MI. Purpose The aim of this study was to evaluate the association of Lp(a) levels with the long-term risk of adverse events in post-MI patients, and to investigate whether diabetes may influence this association. Methods Consecutive MI patients who underwent urgent/emergent coronary angiography at our Institution from February 2013 to June 2019 were prospectively collected. Lp(a) serum concentrations was expressed for increasing range values (≤10, >10–30, >30–50, >50–70, and ≥70 mg/dL). The primary outcome was the recurrence of MI; the secondary outcome was all-cause death. The propensity score weighting technique was used to account for potential confounding between patients with and without diabetes. Results The study population consisted of 1018 post-MI patients (median age: 63 years; 76% males). Diabetes was reported in 280 patients (27.5%). The median value of Lp(a) was 10 mg/dL, and patients with diabetes showed significantly lower Lp(a) levels than patients without diabetes (p=0.025). At a median follow-up of 1121 days, the primary outcome was reported in 109 patients (10.7%), and the secondary outcome in 100 (9.8%). After propensity score weighting, there was a significant association between increasing Lp(a) range values and the primary outcome both in the overall population (p trend = 0.030) and in non-diabetic patients (p trend = 0.009), but not in diabetics. Conversely, no significant association with the risk of all-cause mortality across increasing Lp(a) categories both in the overall population and in the study groups according to the presence or not of diabetes was found. Compared with the lowest Lp(a) category, Lp(a) plasma levels >70 mg/dL were independently associated with the risk of recurrent MI (HR: 3.222; 95% CI, 1.225–8.478, p=0.018) and all-cause death (HR: 2.656; 95% CI, 1.009–6.991, p=0.048) in non-diabetic patients, but not in diabetics. Conclusions In this real-world post-MI population, Lp(a) serum levels were lower in diabetic than in non-diabetic patients. Increasing Lp(a) levels were significantly associated with the risk of recurrent MI, and very high Lp(a) serum concentration (>70 mg/dL) independently predicted recurrent MI and death in non-diabetic patients, but not in diabetics. These results reinforce the importance of routine assessment of Lp(a) levels after MI, particularly in patients without diabetes. Funding Acknowledgement Type of funding sources: None.