Current concept and residual issues of lipoprotein(a) determination for a cardiovascular risk factor

Remnant Cholesterol Levels at Diagnosis May Predict Acute Coronary Syndrome Occurrence During Follow-Up in Patients with Antineutrophil Cytoplasmic Antibody-Associated Vasculitis

Background/Objectives: Previous studies have revealed the predictive potential of remnant cholesterol (RC) for acute coronary syndrome (ACS) occurrence in the general population. However, whether this association applies to patients with antineutrophil cytoplasmic antibody-associated vasculitis (AAV), in which a lipid paradox exists, remains unclear. We investigated whether RC levels at diagnosis could predict ACS occurrence during follow-up in patients with AAV. Methods: This study included 139 patients with AAV. ACS was defined as ST-elevation myocardial infarction (STEMI), non-STEMI, or unstable angina occurring after AAV diagnosis. RC levels were calculated as (total cholesterol)-(low-density lipoprotein cholesterol)-(high-density lipoprotein cholesterol). Patients were categorised into three groups by RC tertiles: highest (≥26.2 mg/dL), middle (19.1-26.1 mg/dL), and lowest (≤19.0 mg/dL) tertile groups. Results: The median age of the 139 patients (male, 31.7%) was 58.0 years. During follow-up, six, two, and one patients were diagnosed with ACS in the highest, middle, and lowest tertile groups, respectively. Patients in the highest tertile group exhibited a significantly lower ACS-free survival rate than those in the lowest tertile (p = 0.030). In the multivariable Cox hazards model, male sex (hazard ratio [HR] 9.054, 95% confidence interval [CI] 1.786-45.910), Birmingham vasculitis activity score (HR 1.147, 95% CI 1.033-1.274), and the highest tertile of RC levels (HR 10.818, 95% CI 1.867-62.689) were significantly and independently associated with ACS occurrence during follow-up in patients with AAV. Conclusions: Our findings indicate that RC levels at diagnosis may predict ACS occurrence during follow-up in patients with AAV, regardless of the traditional cardiovascular risk factors.

Study on the relationship between lipoprotein (a) and diabetic kidney disease

OBJECTIVE

Little is currently known about the role of lipid metabolism in diabetic kidney disease (DKD), warranting further study. The present study sought to investigate the correlation between lipid metabolism and renal function as well as renal pathological grade/score in DKD patients.

METHODS

A total of 224 patients diagnosed with DKD by pathological examination were retrospectively analyzed, of which 74 patients were further evaluated by DKD pathological grade/score. ANOVA was used to investigate serum lipoprotein (a) [Lp (a)] levels in DKD patients with different chronic kidney disease (CKD) stages. Spearman correlation analysis was used to evaluate the relationship between Lp (a) and renal function-related indicators. The DKD pathological grade/score was also evaluated with this method. The receiver operating characteristic (ROC) curve was used to analyze the value of Lp (a) in assessing renal function and pathological changes.

RESULTS

There were significant differences in Lp (a) levels among different CKD stages (H = 17.063, p = 0.002) and glomerular grades (H = 12.965, p = 0.005). Lp (a) levels correlated with serum creatinine (p = 0.000), blood urea nitrogen (p = 0.000), estimated glomerular filtration rate (p = 0.000), 24-h proteinuria (24hUPro, p = 0.000), urine microalbumin (p = 0.000), urine albumin creatinine ratio (p = 0.000), glomerular basement membrane thickness (p = 0.003), and glomerular grade (p = 0.039). ROC curve demonstrated good performance of Lp (a) as an indicator to assess CKD stage 4-5 (AUC = 0.684, p = 0.000), 24hUPro > 3.5 g (AUC = 0.720, p = 0.000), and glomerular grade III-IV (AUC = 0.695, p = 0.012).

CONCLUSIONS

Elevated levels of Lp (a) are associated with decreased GFR, increased proteinuria, and renal pathological progression, suggesting they could be used to monitor changes in DKD patients.

Baseline Low-Density-Lipoprotein Cholesterol Modifies the Risk of All-Cause Death Associated With Elevated Lipoprotein(a) in Coronary Artery Disease Patients

Background: The prognostic value of elevated lipoprotein(a) [Lp(a)] in coronary artery disease (CAD) patients is inconsistent in previous studies, and whether such value changes at different low-density-lipoprotein cholesterol (LDL-C) levels is unclear. Methods and Findings: CAD patients treated with statin therapy from January 2007 to December 2018 in the Guangdong Provincial People's Hospital (NCT04407936) were consecutively enrolled. Individuals were categorized according to the baseline LDL-C at cut-off of 70 and 100 mg/dL. The primary outcome was 5-year all-cause death. Multivariate Cox proportional models and penalized spline analyses were used to evaluate the association between Lp(a) and all-cause mortality. Among 30,908 patients, the mean age was 63.1 ± 10.7 years, and 76.7% were men. A total of 2,383 (7.7%) patients died at 5-year follow-up. Compared with Lp(a) <50 mg/dL, Lp(a) ≥ 50 mg/dL predicted higher all-cause mortality (multivariable adjusted HR = 1.19, 95% CI 1.07-1.31) in the total cohort. However, when analyzed within each LDL-C category, there was no significant association between Lp(a) ≥ 50 mg/dL and higher all-cause mortality unless the baseline LDL-C was ≥ 100 mg/dL (HR = 1.19, 95% CI 1.04-1.36). The results from penalized spline analyses were robust. Conclusions: In statin-treated CAD patients, elevated Lp(a) was associated with increased risks of all-cause death, and such an association was modified by the baseline LDL-C levels. Patients with Lp(a) ≥ 50 mg/dL had higher long-term risks of all-cause death compared with those with Lp(a) <50 mg/dL only when their baseline LDL-C was ≥ 100 mg/dL.