Frequency, risk, and cost of gout-related episodes among the elderly: does serum uric acid level matter?
OBJECTIVE
We examined the association between serum uric acid (SUA) level and the frequency, risk, and cost of gout flares among the elderly.


METHODS
Data were extracted from the Integrated Healthcare Information Services claims database (1999-2005). Patients were included if they had gout, were aged 65 years and older and had both medical and pharmacy benefits, and electronic laboratory data. Patients with gout and gouty episodes were identified using algorithms based on ICD-9-CM codes and medications. Logistic regression and negative binomial regressions were used to study the relationship between SUA concentration and the annual frequency and one-year risk of gout episodes. Generalized linear models were used to examine the direct healthcare costs associated with gout episodes in the 30 days following each episode.


RESULTS
Elderly patients with gout (n = 2237) with high (6-8.99 mg/dl) and very high (> 9 mg/dl) SUA concentrations were more likely to develop a flare within 12 months compared to patients with normal (< 6 mg/dl) SUA levels (OR 2.1, 95% CI 1.7-2.6; OR 3.4, 95% CI 2.6-4.4, respectively). In multivariate regressions, the average annual number of flares increased by 11.9% (p < 0.001) with each unit-increase in SUA level above 6 mg/dl (p < 0.001). Among patients with very high SUA levels, average adjusted total healthcare and gout-related costs per episode were $2,555 and $356 higher, respectively, than those of patients with normal SUA levels (both p < 0.001).


CONCLUSIONS
Higher SUA levels are associated with increased frequency and risk of gout episode, and with higher total and gout-related direct healthcare costs per episode.
Analysis Group, Inc., Boston, Massachusetts 02199, USA. ewu@analysisgroup.com
Eric Q
EQ
Wu
Pankaj A
PA
Patel
Reema R
RR
Mody
Andrew P
AP
Yu
Kevin E
KE
Cahill
Jackson
J
Tang
Eswar
E
Krishnan
D000368:Aged; D000375:Aging; D001774:Blood Chemical Analysis / Q000191:economics; D005260:Female; D006073:Gout / Q000188:drug therapy / Q000191:economics / Q000453:epidemiology; D006074:Gout Suppressants / Q000191:economics; D005102:Health Expenditures; D006801:Humans; D033461:Hyperuricemia / Q000188:drug therapy / Q000191:economics / Q000453:epidemiology; D007345:Insurance Claim Review / Q000706:statistics & numerical data; D008297:Male; D015995:Prevalence; D012008:Recurrence; D012307:Risk Factors; D014481:United States / Q000453:epidemiology; D014527:Uric Acid / Q000097:blood*
D006074:Gout Suppressants; D014527:Uric Acid