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Cosmos Study

Low LDL and HDL Correlated with Increased Likelihood of Myocardial Infarction and Coronary Artery Disease

August 8, 2024
Dual-Team Study
Team A:Kersten Bartelt, RNAlex Piff
Team B:Sam Butler, MDEric Barkley

Key Findings

  • Patients with an average LDL below 90 mg/dL have an increased likelihood of being diagnosed with a myocardial infarction (MI) compared to those with an average LDL of 100-109 mg/dL.  
  • Patients prescribed statins whose average LDL is below 80 mg/dL have an increased likelihood of coronary artery disease (CAD), while those without a lipid-lowering medication prescribed have an increased risk when their LDL is below 100 mg/dL. 
  • All studied patients, regardless of statin use, have an increased likelihood of an MI or a CAD diagnosis when their average HDL is less than 50 mg/dL, compared to patients with a higher average HDL level. 

High cholesterol levels are known to increase the risk of adverse cardiovascular outcomes,1 but the relationship between adverse cardiovascular outcomes and low cholesterol levels has not been well studied. LDL and HDL measure components of a patient’s cholesterol levels. This study explores the relationship between LDL and HDL levels and adverse cardiovascular outcomes. 

We studied patients aged 18 and older with at least five years of cholesterol readings and calculated a weighted average of both their LDL and HDL levels. We analyzed the likelihood of myocardial infarction (MI) or coronary artery disease (CAD) diagnosis following the last cholesterol reading. We adjusted for patient age, sex, race, ethnicity, BMI, history of hypertension, history of diabetes, previous care, and Social Vulnerability Index quartile. We studied patients treated with statins separately from patients not prescribed lipid-lowering medications. 

Among patients prescribed statins, those with an average LDL less than 80 mg/dL generally had an increased likelihood of experiencing an MI or CAD compared to those with an average LDL of 100 mg/dL, as seen in Figure 1. In alignment with previous studies,1 an elevated LDL was correlated with an increased likelihood of MI or CAD diagnosis.  

Figure 1
Likelihood of MI and CAD by LDL Among Statin-Treated Patients
Likelihood of MI and CAD by LDL Among Statin-Treated Patients
Figure 1. The likelihood of MI and CAD diagnosis by average LDL for patients prescribed a statin medication. The LDL values are grouped 30-39 mg/dL, 40-49 mg/dL, etc.

Next, we evaluated the likelihood of MI and CAD by average HDL level among patients prescribed statins. We found that an average HDL less than 50 mg/dL increased the likelihood of MI and CAD, as seen in Figure 2.  

Figure 2
Likelihood of MI and CAD by HDL Among Statin-Treated Patients
Likelihood of MI and CAD by HDL Among Statin-Treated Patients
Figure 2. The likelihood of MI and CAD diagnosis by average HDL for patients prescribed a statin medication. The HDL levels are grouped 20-29 mg/dL, 30-39 mg/dL, etc.

Patients with no lipid-lowering medication prescription generally had an increased likelihood of MI or CAD when their average LDL was less than 100 mg/dL compared to those with an average LDL of 100-109 mg/dL, as seen in Figure 3. Like the patients treated with statins, this population also had an increased likelihood of experiencing an MI or CAD with elevated LDL levels. 

Figure 3
Likelihood of MI and CAD by LDL Among Patients on No Lipid-Lowering Medications
Likelihood of MI and CAD by LDL Among Patients on No Lipid-Lowering Medications
Figure 3. The likelihood of MI and CAD diagnosis by average LDL for patients without a lipid-lowering medication prescription. The LDL values are grouped 30-39 mg/dL, 40-49 mg/dL, etc.

Similar to patients prescribed statins, patients with no lipid-lowering medication and an average HDL less than 50 mg/dL had an increased likelihood of both CAD and MI, as seen in Figure 4. 

Figure 4
Likelihood of MI and CAD by HDL Among Patients on No Lipid-Lowering Medications
Likelihood of MI and CAD by HDL Among Patients on No Lipid-Lowering Medications
Figure 4. The likelihood of MI and CAD diagnosis by average HDL for patients without a lipid-lowering medication prescription. The HDL levels are grouped 20-29 mg/dL, 30-39 mg/dL, etc.

These data come from Cosmos, a dataset created in collaboration with a community of Epic health systems representing more than 256 million patient records from 1,500 hospitals and more than 34,100 clinics from all 50 states and Lebanon. This study was completed by two teams that worked independently, each composed of a clinician and research scientists. The two teams came to similar conclusions. Graphics by Aishwarya Shettigar and Brian Olson. 

References

  1. Lower your LDL. www.heart.org. https://www.heart.org/en/health-topics/cholesterol/hdl-good-ldl-bad-cholesterol-and-triglycerides/lower-your-ldl. Accessed June 14, 2024.