Research Identifies Independent Risk Factor for Mortality in Patients with Gout

According to research presented at the annual meeting, patients with gout who fail to reach a serum urate target of 6 mg/dL have a higher risk for mortality. The presenters encouraged rheumatologists to “treat to target” in patients with gout in order to improve chances of survival.

A painful form of arthritis, gout occurs when excess uric acid, a waste product, collects in the body and leads to urate crystals in and around joints. The crystals may settle and form tophi that appear under the skin. Gout occurs more often in men, post-menopausal women, and people with kidney disease. Patients can lower serum urate levels and manage gout with diet and lifestyle modifications, as well as medications.

Gout is associated with a higher risk of cardiovascular events and death. Research has shown that increasing severity is associated with risk of death, as reflected in the number of tophi. Previous research also has shown that serum urate levels at baseline and during therapy, flares, and comorbidities all are risk factors for mortality. Therefore, the researchers who presented at the annual meeting assessed whether lowering serum uric acid levels to less than 6 mg/dL would improve risk.

The prospective, follow-up cohort study included 1,193 patients treated at a gout clinic from 1992 to 2017. Of the overall study population, 85 percent had a confirmed diagnosis of gout via microscope or ultrasound, and all patients had had at least one follow-up visit, during which serum uric acid levels were monitored. The study used average serum uric acid level until stabilization as the primary exposure, defined as less than 6 mg/dL versus more than 6 mg/dL.

Patients’ mean serum uric acid level at baseline was 9.1 mg/dL, and 16.3 percent of patients maintained serum uric acid levels of 6 or more mg/dl despite treatment. A total of 158 deaths occurred (a 13 percent overall mortality rate). Twenty-four percent of cases were lost to follow-up.

The mortality rate was significantly higher for patients whose serum uric acid level was greater than 6 mg/dL. After adjusting for age, sex, previous cardiovascular events, and baseline serum uric acid concentration, the researchers found that a serum uric acid level of 6 mg/dL or higher was associated with higher mortality risk. They concluded, consequently, that failure to reach a target serum urate level of 6 mg/dL is an independent predictor of mortality in patients with gout.

Coauthor Fernando Perez Ruiz, MD, PhD, of the Hospital Universitario Cruces in Spain, a coauthor on the study ,urged meeting participants to use a treat-to-target approach for hyperuricemia in gout, rather than treat-to-flare.