Serum urate targets for gout back in the spotlight

4 minute read

Two recent studies validate the way rheumatologists have been practising in recent years, but poor patient adherence to treatment remains a sticking point.

Two recent studies validate the way rheumatologists have been practising in recent years, but poor patient adherence to treatment remains a sticking point.

Achieving an average serum urate concentration of less than 0·36 mmol/L over a six-month period is associated with a reduction or absence of gout flares and resolution of tophi in people with gout during the second year of treatment, a study published in the Lancet Rheumatology has found.

A second study, published in Arthritis & Rheumatology, has found lowering the serum urate target to less than 0.20 mmol/L for patients with erosive gout does not achieve better outcomes than the recommended target of less than 0.30 mmol/L.

Associate Professor Helen Keen, a consultant rheumatologist at Royal Perth Hospital, said the results would probably not come as a great surprise to rheumatologists.

“Both studies I think neither change our practice but indeed validate the way rheumatologists have been practising in recent years,” she said.

“The ACR [American College of Rheumatologists] had previously recommended a treat to target strategy of 0.36 mmol/L (and 0.30 for those with tophi), which was not really based on strong clinical evidence,” she said. “This somewhat justifies the ACR recommendations.”

For erosive gout, said Professor Keen, a target of 0.20 was more difficult to achieve without clinically important improvements over a target of 0.30.

“I think these papers, taken together, suggest that we should be aiming for a target of 0.36, but not for 0.20. It’s unclear that a target of 0.30 will produce better outcomes than 0.36.”

In the first study, researchers analysed patient data from two clinical trials, conducted in the UK and New Zealand, on urate-lowering therapies in people with gout. Individuals who on average achieved a serum urate concentration less than 0·36 mmol/L were defined as serum urate responders (343 patients), while non-responders (245 patients) had an average serum urate of at least 0·36 mmol/L.

Clinical outcomes were assessed between 12 and 24 months, with significantly fewer serum urate responders having a gout flare than non-responders (27% vs 64%).  

Meanwhile, research on erosive gout led by Professor Nicola Dalbeth, an academic rheumatologist at the University of Auckland, has found that lower may not always be better.

In a two-year, double-blind, randomised controlled trial, 104 participants with erosive gout on oral urate-lowering therapy (ULT) and serum urate ≥ 0.30mmol/L were randomly assigned to serum urate target <0.20mmol/L (intensive target) or <0.30mmol/L (standard target, according to rheumatology guidelines).

Although the serum urate was significantly lower in the intensive target group than the standard target group, fewer participants in the intensive group achieved the randomised serum urate target.

The intensive target group required higher allopurinol doses and used more combination therapy. Small increases in CT erosion scores were observed in both groups over two years, with no between-group difference. OMERACT core outcome domains (gout flares, tophus, pain, patient global assessment, health-related quality of life and activity limitation) improved in both groups, with no between-group differences. Adverse event and serious adverse event rates were similar between groups.

Dubbo rheumatologist and head of Sydney University’s Clinical School of Medicine at the School of Rural Health, Professor Mark Arnold, said the TTT issues for gout were overshadowed by the problem of poor patient adherence to treatment.

“Most rheumatologists have been doing treat to target for at least a decade,” he said.

He acknowledged that only a minority of gout patients ended up seeing a rheumatologist, and this was another barrier to successful outcomes, given that the management of gout required an ongoing treatment protocol.

“We should be almost delighted to see people with gout because we’re almost always on a winner – provided they stick to the treatment plan,” he said.

Lancet Rheumatol, online 5 November 2021

Arthritis Rheumatol, online 20 December 2021

End of content

No more pages to load

Log In Register ×