CHICAGO—Uncontrolled serum uric acid in patients with gout is associated with an increased risk of developing kidney disease and diabetes, according to the findings of two studies presented at the American College of Rheumatology annual meeting.
In one study, Eswar Krishnan, MD, of Stanford University in Palo Alto, Calif., and colleagues studied 2,116 veterans with gout. The group was 53% white and had an average age of 62.6 years. Subjects generally were obese. To be included in the study, subjects had to have at least two gout diagnoses. The average follow-up time was 80 months. Patients with controlled serum uric acid levels had significantly higher renal disease-free rates at year 1, 2, and 3 compared with subjects who had uncontrolled serum uric acid (96% vs. 92%, 93% vs. 87%, and 90% vs. 82%, respectively). Uncontrolled serum uric acid, defined as a level above 7 mg/dL, was associated with a significant 43% increased risk of renal disease, after adjusting for confounding factors.
The other study, by the same team of investigators, focused on 1,923 veterans (52% white, average age 62.9 years), also with an average follow-up of 80 months. Major comorbidities at baseline included hypertension (93% of patients), hyperlipidemia (64%), and cardiovascular diseases (30%). Patients with controlled serum uric acid had significantly higher diabetes-free rates at year 1, 2, and 3 compared with subjects who had uncontrolled serum uric acid (96% vs. 94%, 91% vs. 88%, and 87% vs. 81% respectively). After adjusting for confounding factors, uncontrolled serum uric acid was associated with a significant 19% increased risk of developing diabetes.
For both studies, the first serum uric acid measurement was assigned as the index date. The investigators identified renal disease using ICD-9-CM codes and dialysis procedure codes. They excluded patients who had renal disease prior to the index date. The researchers identified diabetes using ICD-9-CM codes, use of antidiabetic medications, or hemoglobin A1c of 6.5 or higher.