(HealthNewsDigest.com) – CHICAGO – Failure to reach a serum urate target of 6 mg/dl independently predicts mortality in patients with gout, and a treat-to-target gout control strategy should be considered as a way to improve a patient’s chance of survival, according to new research findings presented this week at the 2018 ACR/ARHP Annual Meeting (Abstract #869).
Gout is a painful form of arthritis, and it occurs more often in men, post-menopausal women and people with kidney disease. Gout happens when excess uric acid, a waste product, collects in the body, and leads to urate crystals depositing in and around the joints. Crystals may settle and form tophi that appear under the skin. Diet and lifestyle modification, as well as medications may help patients lower serum urate levels and manage gout.
Gout is associated with a higher risk of cardiovascular events and death. Research shows that increasing gout severity is associated with risk of death, and is reflected in the number of tophi. In 2014, a group of European researchers published a study analyzing gout patients in Spain and found that several variables contributed to higher mortality risk, including serum urate levels at baseline and during therapy, flares and comorbidities. In their new study, these researchers evaluated whether lowering serum uric acid levels to a target of less than 6 mg/dl would improve mortality risk in individuals with gout.
At the time of their first study, “700 patients were available for an analysis that showed that, among others, severity of gout was associated with increased risk of mortality, but we could not yet find a signal for serum urate while on treatment,” said Fernando Perez Ruiz, MD, PhD, Senior Specialist, Rheumatology Division, Hospital Universitario Cruces in Spain, and the study’s co-author. “That was to assume that once you develop severe gout, treatment has no impact on reducing the risk of mortality. Our results were afterwards replicated by colleagues from New Zealand. Doubling the number of our patients in this study, and with a greater number of patients failing to reach the serum urate target, we have found new signals for not reaching therapeutic target serum urate levels.”
The prospective, follow-up cohort study included 1,193 patients treated at a gout clinic from 1992 to 2017, and 85 percent of these patients had confirmed diagnosis of gout with either microscope or ultrasound. All had at least one follow-up visit. The researchers confirmed mortality from medical records, patients’ families or local death registries. Patients’ serum uric acid levels were monitored during follow-up, and the study used the average serum uric acid level until stabilization as the primary exposure, defined as less than six mg/dl versus more than six mg/dl.
Variables and potential confounders included age, sex, body-mass index (BMI), previous treatment with urate-lowering drugs, the number of joints affected at entry to the study, presence of subcutaneous tophi, radiographic evidence of articular damage, number of gout flares in the year before evaluation, previous cardiovascular disease diagnosis, loop diuretic use, alcohol intake, diabetes, hypertension, hyperlipidemia and renal function impairment. The researchers used the Kaiser Permanente comorbidity model to risk-stratify patients from low to high death risk.
The mean serum uric acid level at baseline was 9.1 mg/dl, and 16.3 percent of patients maintained serum uric acid levels of six or more mg/dl despite treatment. There were a total of 158 deaths among participants in the study, which represents a 13 percent overall mortality rate. There was a loss to follow-up in 286 cases, or 24 percent. Overall crude mortality rate was 32.7 per 1,000 patient-years. This was significantly higher for patients whose serum uric acid level was over six mg/dl(80.9 per 1,000 person-years). After adjusting for age, sex, previous cardiovascular events, and baseline serum uric acid concentration, a serum uric acid levelof six mg/dl or higher was associated with higher mortality risk, or a hazard ratio of 2.39. Failure to reach a target serum urate level of six mg/dl is an independent predictor of mortality in gout patients, the study concluded.
“There are two current approaches for hyperuricemia in gout: treat-to-target interventions to reach therapeutic serum urate levels, or treat to flare unless severe gout develops,” said Dr. Perez Ruiz. “This new analysis shows that although a signal for developing severe gout remains, reaching serum urate therapeutic target is associated with lower mortality risk than being over target. Although we cannot exclude other variables not included in our database, such as control of comorbid conditions, our results encourage making any clinically acceptable effort to reach and maintain serum urate levels on target. Keep in mind that development of severe gout is not a desirable outcome either.”
About the ACR/ARHP Annual Meeting
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About the American College of Rheumatology
The American College of Rheumatology is an international medical society representing over 9,400 rheumatologists and rheumatology health professionals with a mission to empower rheumatology professionals to excel in their specialty. In doing so, the ACR offers education, research, advocacy and practice management support to help its members continue their innovative work and provide quality patient care. Rheumatologists are experts in the diagnosis, management and treatment of more than 100 different types of arthritis and rheumatic diseases. For more information, visit www.rheumatology.org.