Elevated Serum Uric Acid Links to Heart Relaxation Problems in Autoimmune Disease Patients

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Elevated Serum Uric Acid Links to Heart Relaxation Problems in Autoimmune Disease Patients

Autoimmune diseases like systemic lupus erythematosus (SLE) and rheumatoid arthritis (RA) are often associated with joint pain, skin rashes, or fatigue—but they can also quietly damage the heart. One underdiagnosed heart issue in this group is left ventricular diastolic dysfunction (LVDD), a condition where the heart’s left chamber struggles to relax between beats. LVDD is “subclinical,” meaning it rarely causes obvious symptoms early on, yet it raises the risk of heart failure and other serious outcomes. But could a common blood marker—serum uric acid (SUA)—play a role in LVDD for people with autoimmune diseases? A 2022 study from researchers at West China Hospital, Sichuan University, set out to answer this question.

What the Study Examined

The team analyzed data from 5,873 patients with confirmed autoimmune diseases (most with SLE or RA) who were admitted to the hospital between 2011 and 2017. To focus on the link between uric acid and heart function, they excluded patients with:

  • Gout (a condition directly caused by high uric acid),
  • Atrial fibrillation (an irregular heart rhythm),
  • Structural heart disease (e.g., valve defects).

Heart health was assessed using transthoracic echocardiograms (TTE), a noninvasive test that measures heart size, thickness, and function. LVDD was defined using European Society of Cardiology (ESC) guidelines: either a ratio of blood flow (E/e’) ≥13 (a marker of poor relaxation) or a combination of thickened heart muscle (LV hypertrophy) and an enlarged left atrium (LA enlargement) if E/e’ was lower and the heart’s pumping function (ejection fraction) was normal (≥50%).

Key Findings: Uric Acid and LVDD Go Hand-in-Hand

Patients were split into four groups (“quartiles”) based on their SUA levels:

  • Q1 (lowest): 49–222 μmol/L (1,461 patients)
  • Q2: 223–283 μmol/L (1,468 patients)
  • Q3: 284–362 μmol/L (1,469 patients)
  • Q4 (highest): 363–996 μmol/L (1,472 patients)

Nearly 55% of those in Q4 had hyperuricemia (SUA >420 μmol/L), the threshold for abnormally high uric acid.

The most striking result? LVDD rates rose sharply with higher uric acid levels:

  • Q1: 21.7% of patients had LVDD
  • Q2: 25.4%
  • Q3: 26.9%
  • Q4: 36.2%

Even after adjusting for other risk factors (age, high blood pressure, diabetes, kidney function, and medications), people in the highest uric acid group (Q4) were 1.78 times more likely to have LVDD than those in the lowest group (Q1). This means uric acid’s link to LVDD is independent of other known heart risks.

Other Factors That Raised LVDD Risk

The study also confirmed that traditional cardiovascular risk factors matter for autoimmune patients:

  • Older age: Each year of age increased LVDD risk by ~4.5%.
  • High blood pressure: Patients with hypertension were 2.2 times more likely to have LVDD.
  • Kidney insufficiency: Impaired kidney function raised risk by 33%.
  • Sex: Women were nearly twice as likely to have LVDD as men—consistent with autoimmune diseases being more common in women.

Why Uric Acid Matters for Autoimmune Patients

Uric acid is often seen as a “waste product,” but it’s also a pro-inflammatory molecule. Chronic inflammation is a hallmark of autoimmune diseases, and high uric acid may worsen this inflammation—damaging blood vessels and making the heart muscle stiffer (a key driver of LVDD). For patients already living with systemic inflammation, elevated uric acid could act as an “extra trigger” for heart damage.

Limitations to Keep in Mind

As a retrospective study (using past medical records), the research can’t prove that high uric acid causes LVDD—only that they’re strongly associated. Other limitations include:

  • No data on how long patients took medications (e.g., uric acid-lowering drugs).
  • No long-term follow-up to see if LVDD led to heart failure or other events.

What This Means for Patients and Doctors

For patients with autoimmune diseases, this study highlights the need to monitor not just joint or skin symptoms but also heart health—including uric acid levels. Simple lifestyle changes (e.g., reducing high-purine foods like red meat, alcohol, and seafood) may help lower uric acid and protect the heart.

For doctors, the findings add to growing evidence that uric acid is more than just a marker for gout—it’s a potential modifiable risk factor for cardiovascular disease in autoimmune patients. While uric acid-lowering drugs (like allopurinol) are used for gout, more research is needed to see if they can prevent or reverse LVDD in this group.

Study Details

This research was conducted by Yu Kang, Zixuan Yang, Tong Wang, Xiaojing Chen, Qing Zhang, Qibing Xie, and Mian Wang from the Department of Cardiology and Rheumatology at West China Hospital, Sichuan University. It was published in the Chinese Medical Journal in 2022.

You can access the original study at doi.org/10.1097/CM9.0000000000001902.

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