Association of lipoprotein(a) with all-cause and cause-specific mortality: A prospective cohort study

Novel Therapies for Lipoprotein(a): Update in Cardiovascular Risk Estimation and Treatment

PURPOSE OF REVIEW

Lipoprotein(a) is an important causal risk factor for cardiovascular disease but currently no available medication effectively reduces lipoprotein(a). This review discusses recent findings regarding lipoprotein(a) as a causal risk factor and therapeutic target in cardiovascular disease, it reviews current clinical recommendations, and summarizes new lipoprotein(a) lowering drugs.

RECENT FINDINGS

Epidemiological and genetic studies have established lipoprotein(a) as a causal risk factor for cardiovascular disease and mortality. Guidelines worldwide now recommend lipoprotein(a) to be measured once in a lifetime, to offer patients with high lipoprotein(a) lifestyle advise and initiate other cardiovascular medications. Clinical trials including antisense oligonucleotides, small interfering RNAs, and an oral lipoprotein(a) inhibitor have shown great effect on lowering lipoprotein(a) with reductions up to 106%, without any major adverse effects. Recent clinical phase 1 and 2 trials show encouraging results and ongoing phase 3 trials will hopefully result in the introduction of specific lipoprotein(a) lowering drugs to lower the risk of cardiovascular disease.

Causal association of blood lipids with all-cause and cause-specific mortality risk: a Mendelian randomization study

Dyslipidemia has long been implicated in elevating mortality risk; yet, the precise associations between lipid traits and mortality remained undisclosed. Our study aimed to explore the causal effects of lipid traits on both all-cause and cause-specific mortality. One-sample Mendelian randomization (MR) with linear and nonlinear assumptions was conducted in a cohort of 407,951 European participants from the UK Biobank. Six lipid traits, consisting of low-density lipoprotein cholesterol (LDL-C), high-density lipoprotein cholesterol (HDL-C), triglycerides, apolipoprotein A1 (ApoA1), apolipoprotein B (ApoB), and lipoprotein(a), were included to investigate the causal associations with mortality. Two-sample MR was performed to replicate the association between each lipid trait and all-cause mortality. Univariable MR results showed that genetically predicted higher ApoA1 was significantly associated with a decreased all-cause mortality risk (HR[95% CI]:0.93 [0.89-0.97], P value = 0.001), which was validated by the two-sample MR analysis. Higher lipoprotein(a) was associated with an increased risk of all-cause mortality (1.03 [1.01-1.04], P value = 0.002). Multivariable MR confirmed the direct causal effects of ApoA1 and lipoprotein(a) on all-cause mortality. Meanwhile, nonlinear MR found no evidence for nonlinearity between lipids and all-cause mortality. Our examination into cause-specific mortality revealed a suggestive inverse association between ApoA1 and cancer mortality, a significant positive association between lipoprotein(a) and cardiovascular disease mortality, and a suggestive positive association between lipoprotein(a) and digestive disease mortality. High LDL-C was associated with an increased risk of cardiovascular disease mortality but a decreased risk of neurodegenerative disease mortality. The findings suggest that implementing interventions to raise ApoA1 and decrease lipoprotein(a) levels may improve overall health outcomes and mitigate cancer and digestive disease mortality.

Lipoprotein(a) and Long-Term Recurrent Infarction After an Acute Myocardial Infarction

Lipoprotein(a) (Lp[a]) is an emerging risk factor for incident ischemic heart disease. However, its role in risk stratification in in-hospital survivors to an index acute myocardial infarction (AMI) is scarcer, especially for predicting the risk of long-term recurrent AMI. We aimed to assess the relation between Lp(a) and very long-term recurrent AMI after an index episode of AMI. It is a retrospective analysis that included 1,223 consecutive patients with an AMI discharged from October 2000 to June 2003 in a single-teaching center. Lp(a) was assessed during index admission in all cases. The relation between Lp(a) at discharge and total recurrent AMI was evaluated through negative binomial regression. The mean age of the patients was 67.0 ± 12.3 years, 379 (31.0%) were women, and 394 (32.2%) were diabetic. The index event was more frequently non-ST-segment elevation myocardial infarction (66.0%). The median Lp(a) was 28.8 (11.8 to 63.4) mg/100 ml. During a median follow-up of 9.9 (4.6 to 15.5) years, 813 (66.6%) deaths and 1,205 AMI in 532 patients (43.5%) occurred. Lp(a) values were not associated with an increased risk of long-term all-cause mortality (p = 0.934). However, they were positively and nonlinearly associated with an increased risk of total long-term reinfarction (p = 0.016). In the subgroup analysis, there was no evidence of a differential effect for the most prevalent subgroups. In conclusion, after an AMI, elevated Lp(a) values assessed during hospitalization were associated with an increased risk of recurrent reinfarction in the very long term. Further prospective studies are warranted to evaluate their clinical implications.

The relationship of low-density lipoprotein cholesterol and all-cause or cardiovascular mortality in patients with type 2 diabetes: a retrospective study

Background

The optimal levels of low-density lipoprotein cholesterol (LDL-C) in patients with type 2 diabetes (T2D) are not currently clear. In this study, we determined the relationship between various mean LDL-C and all-cause or cardiovascular mortality risks in patients with T2D, stratifying by albumin level, age, sex, and antilipid medication use. We also evaluated the association of LDL-C standard deviation (LDL-C-SD) and all-cause and cardiovascular mortality by type of antilipid medication use.

Methods

A total of 46,675 T2D patients with a prescription for antidiabetic agents >6 months from outpatient visits (2003-2018) were linked to Taiwan's National Death Registry to identify all-cause and cardiovascular mortality. The Poisson assumption was used to estimate mortality rates, and the Cox proportional hazard regression model was used to assess the relative hazards of respective mortality in relation to mean LDL-C in patient cohorts by albumin level, age, sex, and antilipid use adjusting for medications, comorbidities, and laboratory results. We also determined the overall, and anti-lipid-specific mortality rates and relative hazards of all-cause and cardiovascular mortality associated with LDL-C-SD using the Poisson assumption and Cox proportional hazard regression model, respectively.

Results

All-cause and cardiovascular mortality rates were the lowest in T2D patients with a mean LDL-C > 90-103.59 mg/dL in the normal albumin group (≥ 3.5 g/dL). Compared to T2D patients with a mean LDL-C > 90-103.59 mg/dL, those with a mean LDL-C ≤ 77 mg/dL had an elevated risk of all-cause mortality in both the normal and lower albumin groups. T2D patients with a mean LDL-C ≤ 90 and > 103.59-119 mg/dL had relatively higher risk of cardiovascular mortality in the normal albumin group, but in the lower albumin group (<3.5 g/dL), any level of mean LDL-C ≤ 119 mg/dL was not significantly associated with cardiovascular mortality. Increased risks of all-cause and cardiovascular mortality were observed in patients with a mean LDL-C ≤ 77 mg/dL in both sexes and in all age groups except in those aged <50 years, a lower mean LDL-C was not associated with cardiovascular mortality. Similarly, patients with an LDL-C-SD <10^th and > 90^th percentiles were associated with significant risks of all-cause and cardiovascular mortality. In statin users, but not fibrate users, lower and higher levels of mean LDL-C and LDL-C-SD were both associated with elevated risks of all-cause and cardiovascular mortality.

Conclusions

The optimal level of LDL-C was found to be >90-103.59 mg/dL in T2D patients. Lower and higher levels of mean LDL-C and LDL-C-SD were associated with all-cause and cardiovascular mortality, revealing U-shaped associations. Further studies are necessary to validate the relationship between optimal LDL-C levels and all-cause and cardiovascular mortality in patients with diabetes.