Hospitalization rates rise with uncontrolled uric acid levels
By Neil Canavan
Cincinnati, OH—Patients with gout who have uncontrolled serum uric acid levels are much more likely to utilize healthcare resources, such as hospitalizations and outpatient services, compared with patients with gout whose serum uric acid levels are being effectively managed, according to data from a large study of veterans conducted by Eswar Krishnan, MD, MPhil, Assistant Professor of Medicine at the Stanford School of Medicine, Palo Alto, CA, and colleagues. The study was presented in a poster at the October 2012 meeting of the Academy of Managed Care Pharmacy.
Several previous, smaller studies have suggested the relationship between uncontrolled gout and increased healthcare utilization; however, the impact of uncontrolled serum uric acid on “healthcare utilization among veterans with gout has not been well documented,” Dr Krishnan and colleagues suggested. They undertook this investigation in response to the vast number of individuals in the Veterans Affairs system and the rising incidence of gout as the population ages.
The data came from medical records from the Veterans Integrated Services Network between January 2002 and January 2011. The time course was divided into 6-month cycles. Mean serum uric acid levels were estimated for each 6-month cycle, with linear extrapolation used to estimate serum uric acid for any 6-month period in which no measurement was taken.
To qualify for the analysis, patients had to be aged >18 years, have had at least 2 diagnoses of gout, have a minimum of 2 serum uric acid measures within the eligibility period, have at least 1 year of follow-up, and have no comorbid inflammatory diseases.
A total of 2553 veterans with gout were included in the analysis. All participants were men (average age, 63.5 years), approximately 52% were white, and the mean body mass index was 31.1 kg/m2.
Uncontrolled serum uric acid was defined as ≥7 mg/dL. The average duration of follow-up was approximately 6 years.
The results showed that 50% of the 6-month cycles recorded values of serum uric acid in the uncontrolled range (>7 mg/dL), whereas only 30% of patients had a serum uric acid level at or below the American College of Rheumatology–recommended threshold of 6 mg/dL.
In addition, patients with uncontrolled serum uric acid were at increased risk for all-cause and gout-related hospitalizations (hazard ratios [HRs], 1.25 and 1.49, respectively), as well as an elevated risk for all-cause and gout-related outpatient visits (HRs, 1.32 and 1.09, respectively) versus those with controlled gout.
The numbers of gout-related and non–gout-related hospitalization and outpatient visits were also higher for veterans with uncontrolled gout (HRs, 1.47, 1.12, 1.23, and 1.00, respectively) versus those with controlled gout.
Healthcare utilization was similarly increased, even when the cut-off point was reduced to a less stringent level of >6 mg/dL.