Apolipoprotein A1 Threshold Associated with Increased Cancer Mortality After PCI
The study identified that apolipoprotein A1 (ApoA1) levels in the lowest tertile were associated with significantly increased risk of cancer mortality in patients following percutaneous coronary intervention, with the specific threshold being the lowest third of the distribution in their cohort of 3,835 patients. 1
Specific Findings from the Study
ApoA1 Tertile Distribution and Cancer Mortality Risk
The study divided 3,835 PCI patients into three groups based on ApoA1 tertiles, with the lowest tertile demonstrating significantly higher cumulative incidences of total cancer mortality, gastrointestinal cancer mortality, and lung cancer mortality compared to the highest tertile 1
Multivariable Cox proportional hazard regression analysis, adjusted for cancer-related prognostic factors including smoking status, identified elevated ApoA1 as an independent predictor of decreased risk of total and gastrointestinal cancer mortalities 1
The median follow-up period was 5.9 years (range 0-17.8 years), providing robust long-term outcome data 1
Clinical Context: ApoA1 Levels and Mortality
While the study did not report exact numerical cutoffs for the tertiles, patients in the lowest third of ApoA1 distribution experienced the highest cancer mortality rates 1
This finding contrasts with HDL-C measurements, where no significant differences in cancer mortality rates were observed when patients were divided by HDL-C tertiles, suggesting ApoA1 may be a more sensitive marker than HDL-C for cancer mortality risk in this population 1
Broader Evidence on ApoA1 Levels and Mortality
U-Shaped Relationship with Mortality
A large UK Biobank study of 402,783 participants demonstrated a U-shaped relationship between ApoA1 levels and both cardiovascular and all-cause mortality, with individuals in the highest decile (1.91-2.50 g/L) showing increased mortality compared to the lowest-risk eighth decile (1.67-1.75 g/L) 2
Both very low and very elevated ApoA1 levels are associated with higher cardiovascular and all-cause mortality, with the U-shaped relationship present in both sexes but more pronounced in men 2
Low Lipoprotein(a) and Cancer Risk
- Supporting evidence from a Japanese cohort study of 10,413 participants found that low Lp(a) levels (<80 mg/L) were associated with higher all-cause and cancer death rates, with a hazard ratio of 1.48 (95% CI 1.15-1.92) for cancer deaths 3
Clinical Implications for PCI Patients
Risk Stratification
Preprocedural ApoA1 measurement provides prognostic information for future cancer mortality risk in patients undergoing PCI, independent of traditional cardiovascular risk factors 1
The baseline white blood cell count-to-ApoA1 ratio (WAR) has been identified as an independent predictor of long-term adverse outcomes, with WAR ≥4.635 associated with 92.3% increased risk of all-cause mortality compared to WAR <4.635 4
Management Considerations
While low ApoA1 levels (<120 mg/dL for men, <140 mg/dL for women) are considered abnormal by European guidelines, the specific tertile-based risk stratification in the PCI population suggests that relative ApoA1 levels within the study population are more predictive than absolute cutoffs 5
Focus should remain on lowering ApoB rather than directly raising ApoA1, as evidence for reducing the ApoB/ApoA1 ratio through ApoB reduction is stronger than for ApoA1 elevation 5, 6