Reduced CV outcomes with larger early LDL-c lowering after MI in real-world setting
Low-density lipoprotein cholesterol reduction and statin intensity in myocardial infarction patients and major adverse outcomes: a Swedish nationwide cohort study
Introduction and methods
Clinical trial data suggest that acquired relative CV risk reduction per unit LDL-c reduction is consistent, regardless of baseline LDL-c . Patients with higher baseline LDL-c though benefit most from LDL-c lowering therapy with a larger absolute LDL-c lowering and greatest reduction in mortality . This has been studied in clinical trials enrolling patients with predefined characteristics, but data on the association between LDL-c lowering after myocardial infarction (MI) with long-term outcomes from real-life populations are limited.
Aim of this study was to investigate the association between early LDL-c changes and statin intensity with mortality and major adverse CV outcomes after an MI.
Data from the SWEDEHEART registry was used. This is a Swedish nationwide MI quality registry. Patients admitted with an MI to a coronary care unit in Sweden were included in the registry . This study included 40,607 patients 30-75 years, admitted for MI between Jan 2006 and Dec 2016, who were alive at follow-up, 6-10 weeks after discharge. Outcomes included all-cause mortality, CV mortality, MI, ischemic stroke, hospitalization for heart failure, coronary artery revascularization, and a composite of CV mortality, MI, ischemic stroke and coronary artery revascularization (major vascular event). Median follow-up was 3.8 years (Q1-Q3:1.9-6.5).
- Median LDL-c at time of index event was 3.1 (2.3-3.9) mmol/L and median change was 1.2 mmol/L reduction. Largest mean reduction was achieved in statin naïve patients with a high-intensity statin. Ezetimibe was used by 1% of patients at the index event and 7% at the follow-up visit.
- 27% of patients had LDL-c reduction ≥50%, 57% had LDL-c reduction of <50% and 16% had no reduction or increase in LDL-c.
- A stepwise lower risk of all outcomes with quartiles of larger LDL-reduction was observed. Patients in the 75th percentile of LDL-c reduction (1.85 mmol/L) had a lower hazard of outcomes compared with patients in the 25th percentile (0.36 mmol/L) (for the composite of CV mortality, MI and ischemic stroke: HR 0.77, 95%CI: 0.70-0.84; for all-cause mortality: HR 0.71, 95%CI: 0.63-0.80; for CV mortality: HR 0.68, 95%CI; 0.57-0.81; for MI: HR 0.81, 95%CI: 0.73-0.91; for ischemic stroke: HR 0.76, 95%CI: 0.62-0.93; for heart failure hospitalization: HR 0.73, 95%CI: 0.63-0.85; for coronary artery revascularization: HR 0.86, 95%CI: 0.79-0.94).
- Magnitude of LDL-c reduction was related to the event rates of MACE, all-cause mortality and major vascular event.
- Patients with ≥50% reduction in LDL-c and a high-intensity statin after the follow-up visit had lower incidence of all outcomes compared with patients achieving ≥50% reduction in LDL-c with a low-or medium-intensity statin.
- Patients with LDL-c increase or no reduction had higher event rates and increased risk of all outcomes compared to patients with any LDL-c reduction.
- For every 1 mmol/L reduction in LDL-c was an ~25% relative event rate reduction for major vascular events. Similar results were obtained for outcomes of MACE, all-cause mortality, MI and a larger reduction in event rate for hospitalization for heart failure.
In real-world patients in the SWEDEHEART registry, early LDL-c reduction after an MI was associated with lower incidence and reduced adjusted risk of MACE, all-cause mortality, CV mortality, MI, ischemic stroke, hospitalization for HF and coronary revascularization.
The authors write: ‘The relationship between LDL-c reduction and event rate decline was linear and comparable to the CTTC meta-analysis of statin treatment trials’ .