Increasing Good Cholesterol Not as Effective as Lowering Bad Cholesterol

A normal level of HDL does not necessarily reduce the risk of mortality.

Findings from a recent study suggests that increasing good cholesterol may not be as effective as lowering bad cholesterol when it comes to reducing heart disease.

Other studies have shown that very low and very high levels of good HDL cholesterol are associated with an increased risk of mortality from heart disease, cancer, or other causes. However, the current study, published by the Journal of American Cardiology, found that increasing HDL may not reduce risks and mortality associated with heart disease.

To reduce the risk of a heart attack, many patients are treated with statins to lower bad LDL cholesterol. Statins are able to block the enzyme that is critical to producing cholesterol.

Some patients are resistant to statins, so investigators have looked at whether increasing levels of LDL cholesterol elicit the same effects.

Some patients who are intolerant to statins have the option of being treated with a PCSK9 inhibitor, but the effects of these drugs on cardiovascular morbidity and mortality are unknown. These treatments are also very costly compared with statins, which may prevent certain patients from receiving this treatment.

There were more than 631,000 individuals included in the current study through the CANHEART cohort database. All patients included had no previous heart conditions, and were 40- to 105-years-old living in Ontario, Canada.

This was the first study to examine the relationship between HDL and mortality in patients living in the same environment, exposed to the same healthcare system. Study participants were divided into groups based on their HDL levels.

Investigators then assessed the link between HDL levels of healthier individuals compared with those with less healthy lifestyles. Low levels of HDL were associated with socioeconomic disadvantage, and those who had less healthy lifestyles, more cardiac risks, and more medical comorbidities, according to the study.

When lifestyle factors were adjusted for, lower levels of HDL were still associated with in an increase of mortality, and high levels of HDL was associated with an increased risk of non-cardiovascular death.

Researchers said that these findings are similar to other studies that found a link between low HDL and cardiovascular-related deaths, but this is the first time that a similar relationship has been seen between HDL and all-cause mortality.

Currently, researchers are not sure why high levels of HDL increased levels of non-cardiovascular related deaths. Other studies have indicated that this relationship could be due to increased alcohol consumption, but investigators did not have access to alcohol use data. Additional studies are needed to confirm or dismiss this cause.

The researchers concluded that lowering HDL would not be enough to lower cardiovascular-related deaths.

“The link between good cholesterol and heart disease is complex, but it seems certain that there is a connection between people with low good cholesterol levels and other well-known risk factors for heart disease such as poor diet and exercise habits and other medical conditions,” said lead author of the study Dennis T. Ko, MD, MSc. “Focusing on raising HDL is likely not going to help these patients, but these findings show that one of the best interventions in treating and preventing heart disease continues to be lifestyle changes.”