Study analysis · European Heart Journal · 2023

Lowering LDL cholesterol cuts the relative risk of heart attacks and strokes by 22% — but a new meta-analysis suggests the benefit may shrink with age for people without prior heart disease.

A huge analysis of 59 trials found that for every 1 unit drop in bad cholesterol, the relative risk of major heart events drops 22%, and this benefit stays steady over time, except it may get smaller as people without prior heart disease get older.

Reading level
Low certainty
Level 1a · Systematic review of RCTs

Overview

What the study found

The study in plain English — the bottom line, every takeaway we extracted, and what to do with them.

In simple terms

This study combined the results of 59 randomized trials, which is the best way to test if a treatment works. It shows that lowering LDL cholesterol reduces the chance of heart attacks and strokes, and this benefit stays the same over time for people who already have heart disease, but might be smaller in older people who don't yet have heart disease. However, because we only saw the summary, we can't check all the details.

What’s the bottom line?

Scientists combined 59 studies to see if lowering LDL cholesterol reduces heart problems and if that effect changes with time or age.

How strong is this study?

The study is very large, with almost 400,000 people from 59 trials, so the main result is probably reliable. But we only have the short summary, not the full paper, so we can't be sure how well each trial was done or if there are hidden problems. Still, the huge number of people makes the main finding fairly trustworthy.

Reporting

0 / 100

  • COI disclosureconflicts of interest not disclosed
  • Data availabilitydata not shared
  • Code availabilitycode not shared
Methodology

38 / 100

  • Randomizationrandomization unclear
  • Blindingblinding unclear
  • Control groupno control group
  • Sample size (n=394989)+20/20
  • Follow-up+10/10
Publication

100 / 100

Statistical

77 / 100

  • P-values+15/15
  • Effect size+20/20
  • Confidence intervals+15/15
  • Pre-registrationnot pre-registered

Each component is scored out of 100 and then capped by the study design — a case series cannot reach the ceiling a randomised trial can, however well it is reported.

Where it sits

RCT reviews

Max 100

Randomized Trials

Max 90

Reviews of Cohort Studies

Max 85

Cohort Studies

Max 72

Reviews of Case-Control Studies

Max 63

Case-Control Studies

Max 58

Cross-Sectional & Case Series

Max 50

Expert Opinion

Max 5
StrongerWeaker
Reviews of RCTs (Meta-analyses)
Level 1a
52

52 / 100

Probability of being correct

The highest quality evidence. Systematic reviews and meta-analyses that pool randomized controlled trials, giving the most reliable summary of experimental evidence.

This design can establish causation. The overall effect of LDL-c reduction on cardiovascular events is supported by randomized controlled trials, allowing causal inference for that main effect. However, the specific findings regarding the course of effects over time and age are based on meta-regression of trial-level data, which is observational and cannot establish causation for time or age effects. Additionally, abstract-only availability prevents verification of randomization, blinding, and risk of bias.

No Conflicts

No conflicts of interest identified

Not Disclosed

No conflicts of interest or funding disclosures were present in the provided abstract.

Undisclosed — Suspicious

Only the abstract was provided, which lacks any conflict of interest or funding statements. The study appears to be a meta-analysis of published trials, but author affiliations and funding sources are unknown.

Key takeaways

  1. 01

    Each 1 mmol/L drop in LDL cholesterol reduced the relative risk of major heart events by 22% (RR 0.78).

  2. 02

    The effect stayed the same over up to 9.7 years.

  3. 03

    In people without prior heart disease, the benefit got smaller with age (9.4% higher relative risk per 5 years).

  4. 04

    In people with prior heart disease, the benefit stayed the same with age.

  5. 05

    The study didn't report absolute risk reduction, so we can't say how many fewer heart attacks per 1000 people.

  6. 06

    The relative risk reduction of 22% means if someone's risk was 10%, it would drop to about 7.8% with that LDL reduction, but the baseline risk is unknown from this abstract.

Surprising findings

  • The relative risk reduction from LDL cholesterol lowering may decrease with age in primary prevention, but remains stable in secondary prevention.It contradicts the assumption that relative treatment benefits are uniform across age groups, and suggests that the biology or risk profile of older primary-prevention patients may differ.

Practical takeaways

If you have prior cardiovascular disease, LDL cholesterol lowering appears to maintain its relative benefit over time, even up to about 9.7 years.

This is based on an abstract only; absolute risk reduction was not reported, and full methodology cannot be verified. This is not medical advice.

low confidence

If you are older and have never had a heart attack or stroke, the relative benefit of LDL lowering may be smaller, so discuss individual risks and benefits with your doctor.

The study only reports relative effects; absolute risk and clinical decision thresholds are not available in the abstract. Full paper not available.

low confidence

Why this study matters

The headline number: 22% relative risk reduction

In a meta-analysis of 59 randomized controlled trials with 394,989 participants and 49,642 major vascular events, each 1 mmol/L reduction in LDL cholesterol reduced the relative risk of major vascular events by 22% (RR 0.78, 95% CI 0.75-0.81). The absolute risk reduction was not reported in the abstract.

This is a massive synthesis of evidence, but the 22% is a relative risk reduction — the actual number of people who avoid an event (absolute risk) is not given, so the real-world benefit per person is unclear.

Benefit doesn't fade over time

The relative risk reduction remained stable over follow-up durations ranging from 0.9 to 9.7 years. There was no significant association between follow-up duration and treatment effect (meta-regression p=0.615; RR for change per year 0.994, 95% CI 0.971-1.017).

Many people wonder if cholesterol drugs stop working after years of use. This analysis suggests the relative benefit stays consistent for up to about a decade.

Primary vs secondary prevention: different relative benefits

The average relative risk reduction was slightly larger in primary prevention (RR 0.74; 95% CI 0.68-0.81) than in secondary prevention (RR 0.80; 95% CI 0.77-0.83). Primary prevention means people without prior cardiovascular disease; secondary means people with prior disease.

People without prior heart disease may get a larger relative reduction per unit LDL drop, but the absolute benefit still depends on their baseline risk.

Age matters in primary prevention — but not secondary

In primary prevention, the relative risk reduction decreased with age (RR for change per 5 years 1.094; 95% CI 1.028-1.165; p=0.018). In secondary prevention, the effect remained stable with age (RR for change per 5 years 0.986; 95% CI 0.943-1.031; p=0.533).

This challenges a one-size-fits-all approach: older adults without prior heart disease may get less relative benefit from LDL lowering, while those with prior disease maintain benefit.

Want the whole report?

Detailed mode opens the full scientific breakdown — every score component, the methodology, conflicts of interest, the evidence analysis behind each claim, and the raw study data.

Standing

Who’s using this study?

The videos and claims on this site that lean on this study, and the researchers who wrote it.

1 video from Dr Brad Stanfield cite this study, drawing 1 claim from it.

Dr Brad Stanfield
Supports
All 1 video reference this study through extracted claims.

Authored by

5 researchers

If this is your work, this is how we attribute it on Fit Body Science. P.M. Burger is listed as the lead author.