UL study shows ‘alarming rise’ in uric acid levels in patients

Professor Stack, Foundation Chair of Medicine at Graduate Entry Medical School

One in four people in the Irish health system have elevated blood levels of uric acid, according to a new study led by researchers at the Graduate Entry Medical School (GEMS), University of Limerick. The largest study of its kind in Ireland has found that Uric Acid levels here increased at an ‘alarming’ rate from 2006 to 2014.

Uric acid has been linked with a range of conditions from gout to kidney disease.

In a Health Research Board supported study of over 128, 000 patients in the Irish health system, researchers found that uric acid levels increased by 21 per cent over a nine year period, with increases seen in all age groups from young adults to the very elderly.

Uric acid is a by-product of the body’s metabolism and is associated with conditions such as heart disease, high blood pressure, stroke and kidney disease.

The researchers used data from the National Kidney Disease Surveillance System, based in UL’s Graduate Entry Medical School, to track the levels of uric acid in patients from 2006-2014 in the midwest and northwest regions.

“What we found was astonishing,” says Professor Austin Stack, Principal Investigator for the UL Kidney Health Consortium and a senior author of the study.

“In 2006 just over one fifth of all patients (20.1 per cent) were estimated to have elevated uric acid levels in their blood. By 2014, this number had increased to almost one quarter (24.5%).”

While this was not a national random sample, it included a very large group of patients from all demographics within the health system. “We identified rising levels of uric acid in every subgroup of patients and in all clinical settings between 2006-2014; whether they attended outpatient clinics, were hospitalised as inpatients, or visited their GP in general practice,” says Professor Stack.

Uric acid is a waste product and produced when the body breaks down ‘purines’ found in many foods, drinks and alcohol. About 30 per cent of uric acid production is attributable to diet and lifestyle factors such obesity and food intake, especially foods containing fructose such as sugary drinks.

“There is increasing evidence to suggest that high uric acid levels may be a causal factor in kidney disease,” says Professor Austin Stack. “Each year in Ireland around 400 people start on dialysis for kidney failure. However, kidney disease is detected in around 15 per cent of all patients entering the Irish health system.”

Uric acid is also a cause of Gout, a common arthritis when uric acid crystals build up in the joints.

“In addition, and possibly even more concerning, high levels of uric acid are directly linked to the development of several major diseases including high blood pressure, diabetes, kidney disease, heart attacks and strokes,” says Professor Stack, who is Foundation Chair of Medicine at GEMS and Consultant Nephrologist at the University Hospital Limerick. “Rising blood levels of uric acid mean that more patients are at risk of these serious conditions.”

This is the first study of its kind to be conducted in Ireland, but previous studies in the UK, US and in Europe have identified similar marked increases.

The increases have taken place too rapidly to be explained by genetic changes, says Professor Stack. “These steep increases in a nine year period are more likely to be linked to lifestyle factors. Excessive uric acid production is a biochemical signal that something is going wrong with the body.”

Lead author of the study Dr Arun Kumar, a clinical tutor at GEMS and researcher in the UL Kidney Health Consortium, commented on the rate of growth in uric acid concentrations. “In real terms levels of uric acid in the blood increased from 314.6 to 325.6 µmol/L. While this seems a relatively small increase in amount, it should be noted that it has occurred over a relatively short period of time and suggests that genetics is unlikely to account for this increase. A far more likely explanation is that lifestyle factors have driven up blood levels of uric acid in Irish people. We are more sedentary, more obese, consume more sugary drinks and are less physically active.”

Uric acid levels can be managed using a combination of lifestyle changes and medication.

Prevalence estimates were highest among elderly patients and those with severely impaired kidney function. The observed growth patterns were not accounted for by changing demographic and clinical profiles. These findings suggest that the burden of excess uric acid, known as hyperuricaemia, is increasing in the Irish health system. Given the emerging body of evidence linking hyperuricaemia to adverse clinical outcomes, the research team concluded that better management of uric acid and its determinants should be a major goal in order to improve patient outcomes.

The study “Temporal trends in hyperuricaemia in the Irish health system from 2006-2014: A cohort study is published by PLOS One and authored by Arun Kumar A. U., Leonard D. Browne, Xia Li, Fahd Adeeb, Fernando Perez-Ruiz, Alexander D. Fraser, Austin G. Stack and is available online here  .