A Routine Blood Marker Could Offer Clues About Cognitive Changes in Heart Failure

Heart failure can affect more than stamina and the ability to stay active.

Some people also notice changes in memory, focus, and thinking. The challenge for health care providers is spotting those changes, especially when they are not easy to see.

A new study suggests that a marker already included in routine blood tests may provide hints about cognitive health in people with heart failure, although it is not ready to be used for screening.

What the study looked at

The research involved 153 adults living with heart failure. Investigators reviewed their prognostic nutritional index, or PNI, a score based on two blood measures: albumin and lymphocytes.

Albumin is a protein that helps maintain fluid balance, while lymphocytes are immune cells that help fight infection.

Together, these values can reflect nutritional status and inflammation.

Participants also completed a cognitive screening test. Researchers then compared those results with PNI scores to see whether the marker was linked to problems with memory and thinking.

Lower PNI scores tracked with cognitive impairment

More than 60% of the participants screened positive for cognitive impairment, and this group had lower PNI scores than those who did not.

After accounting for age, sex, and education, each five-point rise in PNI was associated with lower odds of cognitive impairment.

Put another way, people with higher scores were less likely to screen positive. Still, a high score does not eliminate the possibility of cognitive problems, and a low score does not confirm them.

Adding PNI to a model that already included age, sex, and education did not significantly improve its ability to identify cognitive impairment. PNI also did not outperform albumin alone.

So while PNI was associated with cognitive impairment, the study did not show that it works well as a standalone screening tool.

Why heart failure may affect brain function

Heart failure can reduce blood flow to the brain, which may influence memory and thinking.

Nutrition and inflammation may also contribute, but PNI is not a direct measure of diet quality. Albumin and lymphocyte levels can shift for many reasons, including inflammation, fluid retention, infections, and medications.

Because the study looked at information at only one point in time, researchers could not determine whether lower PNI scores played a role in cognitive impairment or simply appeared alongside it.

Larger studies are needed to find out whether this marker could improve cognitive screening.

Ways to support cognitive health

While researchers continue to study this marker, there are practical steps people can take to protect overall health.

• Report memory changes: Ongoing forgetfulness, difficulty concentrating, or slower thinking should be discussed with a health care provider, especially for people with heart failure. A cognitive assessment can help decide whether more evaluation is needed.
• Focus on nutrition: Try to eat balanced meals with enough protein, a variety of fruits and vegetables, and sufficient food to meet your needs. If heart failure affects your appetite, ask your care team about nutrition support.
• Manage heart failure: Follow your treatment plan, stay active as advised by your care team, and keep up with regular checkups. Caring for heart health is also part of caring for brain health.

Bottom line

Lower PNI scores were linked with cognitive impairment in this group, but the marker cannot replace a proper cognitive assessment.

For people with heart failure, sticking with treatment and speaking up about cognitive changes remain the more useful steps.