A new Mayo Clinic study shows that patients whose gout starts in joints other than the big toe – such as the elbows or knees – are more likely to have recurrent flares than patients whose gout starts in the traditional site. The findings, recently presented in Madrid at the 2013 Annual Congress of the European League Against Rheumatism (EULAR), may help doctors determine which patients should be put on drug therapy to reduce their risk of a subsequent flare, as opposed to being treated with lifestyle changes alone.
Gout – a form of inflammatory arthritis that has long been associated with bouts of intense pain and swelling in the big toe – results from higher-than-normal levels of uric acid. Uric acid is a chemical that forms when the body breaks down compounds called purines, found both in cells as well as in certain foods. The excess acid builds up, forming crystals that can cause episodes of pain, heat and swelling in one or more joints.
While some patients can manage gout with diet and lifestyle changes, others need uric acid lowering medications. But opinions differ as to when drug therapy should start. American College of Rheumatology (ACR) guidelines recommend starting uric acid lowering drugs in patients experiencing two or more flares a year. Some doctors take a more cautious approach – waiting for three or more bouts – while others may opt to lower uric acid with medication after just one attack, explains Eric L. Matteson, MD, rheumatology chair at Mayo Clinic in Rochester, Minn., and senior study author.
He adds that at Mayo Clinic, “if a person has a single attack of gout and does not have markedly elevated uric acid, we do not automatically put that patient on urate-lowering therapy [because] it can be years before another attack occurs.”
In an effort to help standardize care, Mayo Clinic researchers decided to investigate whether certain factors might help predict additional flares after the first gout attack.
They followed 46 people for an average of nearly 13 years. Most were men with an average age of 66 and an average uric acid level of 8.1 mg/dL (the normal range in adult men is between 2 and 7.5 mg/dL). For the vast majority (72 percent), gout started in the big toe.
Over the course of the study, 28 patients had at least one subsequent flare, with a total of 101 flares overall. The biggest predictors of repeat attacks? A high uric acid level at the start of the study and gout that originated in a joint other than the big toe.
“We are not certain why this is the case,” Dr. Matteson says. "[But] it was not simply because uric acid levels were higher in [these] cases.”
Researchers say knowing such risk factors can help guide future treatment decisions for gout patients.
“Our study gives a unique outlook on the likelihood of future attacks in patients with incident gout,” explains Tim Bongartz, MD, a Mayo Clinic rheumatologist in Rochester, Minn. and the study’s first author.
“It underlines the importance of risk stratification in patients with gout in order to prevent over- as well as under-treatment,” he says. “Our study indicates that 30 percent of patients with a first gout attack never did experience a second flare during the entire follow-up period.”
Theodore R. Fields, MD, a gout specialist and director of the Rheumatology Faculty Practice Plan at Hospital for Special Surgery in New York, agrees that the study provides important information for doctors and patients.
“The question of how many gout attacks a patient needs to justify urate-lowering therapy is an ongoing discussion. [So] it would be very helpful for rheumatologists to have some clues in a particular patient's case that they were at higher risk of further attacks in the near future. This data can be helpful to rheumatologists treating patients after their first gout attack, while trying to decide if urate-lowering therapy is indicated,” he says.
Dr. Bongartz adds that the implications of the study may extend beyond painful joints. “Gout is often associated with other diseases such as obesity, hypertension and hyperlipidemia [high cholesterol and triglycerides],” he says. “I like to refer to gout as a warning light that is alerting us to other problems.”