FRI0246 Investigating the effect of serum urate levels on gout flare rates in a large-scale u.s. administrative claims database
Authors: P. Herzog, A.-C. Fu, J. Lim, D.C. Taylor
Journal: Annals of the Rheumatic Diseases (2018)

<h3>Background</h3> Reducing patients' serum urate (sUA) levels has long been the focus of gout treatments. Current evidence suggests that sUA levels≥6.0 mg/dL significantly increase a subject's risk of an acute gout attack or "flare." <h3>Objectives</h3> To investigate the effects of sUA levels on gout flare rates (GFLR) over a 5 year period in a large-scale US commercial claims database. <h3>Methods</h3> Truven MarketScan administrative claims data from 2010 to 2015 were used for this analysis. The study population was patients with gout whose index gout diagnosis was defined as first gout diagnosis. Index sUA date (IsD) was defined as the sUA result closest to, but not preceding, a subject's index gout diagnosis. Patients were included if they had continuous health plan enrollment during the year prior to and after their IsD. Patients without an sUA result after their index gout diagnosis were excluded. Three sUA comparison groups were created based on mean sUA values calculated from sUA measurements at IsD through follow-up. Person-time was defined as time between IsD to the end of continuous enrollment or to the end of the study period, whichever came first. Gout flares were determined via a published algorithm Halpern 2009 combining health care visits and prescriptions by using ICD9/10, HCPCS, and NDC codes. Subjects' annual GFLR were calculated as their number of flares per person-time. Mean GFLR were calculated for each sUA comparison group. A generalised linear model was developed to investigate the effect of sUA levels on GFLR after adjusting for demographics and regions. <h3>Results</h3> 15 140 subjects were included in the analysis. Most subjects were male (78%) and from the south (47%) with a mean age of 52 years. Mean sUA was 6.9 mg/dL (min=1.4, max=17.5) where 58% of patients had sUA between 6.0 and 9.0 mg/dL. Subjects were followed for 2.1 years on average. sUA ≥6.0 and&lt;9.0 mg/dL (Group 2), and sUA ≥9.0 mg/dL (Group 3) were both associated with increased gout flare rates compared to sUA &lt;6.0 mg/dL (Group 1). Group 3 had 1.540 times of the annual flare rate of Group 1. Male sex and increasing age were associated with increased GFLR. North central, south, and west US regions were all positively associated with GFLR in relation to the northeast (table 1). <h3>Conclusions</h3> These results suggest that higher sUA levels are associated with higher flare rates and that sUA level may be an indicator of GFLR. This finding may encourage health providers to prioritise reducing sUA levels in gout patients to reduce the frequency of gout flares and improve gout management. <h3>References</h3> [1] Halpern R, et al. The effect of serum urate on gout flares and their associated costs. J Clin Rheumatol2009;15(1):3–7. [2] Halpern R, et al. Impact of noncompliance with urate-lowering drug on serum urate and gout-related healthcare costs: administrative claims analysis. Curr Med Res Opin2009;25(7):1711–1719. [3] Abhishek A, et al. Association of serum uric acid and disease duration with frequent gout attacks: a case-control study. Arthritis Care Res (Hoboken)2016;68(10):1573–1577. [4] Sarawate CA, et al. Serum Urate Levels and Gout Flares. J Clin Rheumatol2006;12(2):61–65. <h3>Acknowledgements</h3> Study funded by Ironwood Pharmaceuticals. <h3>Disclosure of Interest</h3> P. Herzog Employee of: Ironwood Pharmaceuticals, Inc., A.-C. Fu Employee of: Ironwood Pharmaceuticals, Inc., J. Lim Employee of: Ironwood Pharmaceuticals, Inc., D. Taylor Shareholder of: Ironwood Pharmaceuticals, Inc., Employee of: Ironwood Pharmaceuticals, Inc.