Both high and low LDL cholesterol can lead to sudden cardiac arrest in diabetes patients: Study

The researchers in their study, published in Cardiovascular Diabetology, observed a U-shaped association between SCA and LDL-cholesterol levels, with the lowest and highest LDL-cholesterol group having a higher risk of sudden cardiac arrest than others.

"Our findings imply that in diabetes patients, low level of LDL-cholesterol can be a surrogate marker for increased SCA risk," Yun Gi Kim and colleagues from South Korea wrote in their study. "This paradoxical association should be recognized and applied in clinical preventive measure."

Dyslipidemia, measured as LDL-cholesterol, is an established risk factor for cardiovascular disease (CVD), which is more pronounced in diabetes patients. Not much is known about the association between LDL-cholesterol levels and the risk of SCA in patients with diabetes. Sudden cardiac arrest is an unexpected sudden loss of cardiac contraction without a warning sign.

Against the above background, the research team aimed to investigate the association between LDL-cholesterol and the risk of SCA in the diabetes population based on the nationwide database of K-NHIS (Korean National Health Insurance Service).

The study included patients who received general examinations from 2009 to 2012 and were diagnosed with type 2 diabetes mellitus (T2DM). Two million six hundred two thousand five hundred seventy-seven patients were included in the study, with a mean follow-up duration of 6.86 years. SCA event identified with the International Classification of Disease code was the study's primary outcome.

The authors reported the following findings:

• Twenty-six thousand three hundred forty-one cases of sudden cardiac arrest were identified.
• Overall, SCA incidence was highest in the lowest LDL-cholesterol group (< 70 mg/dL) and decreased linearly as LDL-cholesterol rises, till 160 mg/dL.
• Adjustment of covariates resulted in a U-shape association, with the highest SCA risk in the highest LDL-cholesterol group (≥ 160 mg/dL) followed by the lowest LDL-cholesterol group (< 70 mg/dL).
• In subgroup analysis, the U-shape association between SCA risk and LDL-cholesterol was more pronounced in non-obese people, males and those who did not use statins.

Both high and low LDL cholesterol is associated with an increased risk of sudden cardiac arrest. The researchers could not establish cause and effect relationship based on the study; despite this, they suggest that low LDL-cholesterol can be a surrogate marker for a high-risk group for SCA among diabetes patients.

The team concluded, "to apply this finding to clinical field and preventive SCA measures, mechanisms for this reversed relationship between LDL-cholesterol and SCA needs further investigation.

Reference:

Kim, Y.G., Jeong, J.H., Han, KD. et al. Association between low-density lipoprotein cholesterol and sudden cardiac arrest in people with diabetes mellitus. Cardiovasc Diabetol 22, 36 (2023). https://doi.org/10.1186/s12933-023-01769-9