Objective: To compare characteristics of gout in Hmong patients versus whites, and examine if Hmong ethnicity is associated with risk of tophaceous gout.
Methods: A retrospective chart review of Hmong and White patients with gout in a large health care system (Health Partners) in St. Paul, Minnesota, from January 2001 to March 2008, to compare clinical characteristics and risk factors for gout. Multivariable-adjusted hierarchical logistic regressions examined the association of Hmong ethnicity with risk of tophaceous gout, adjusting for age, sex, hypertension, diuretic use, and kidney function.
Results: The analytic dataset consisted of 89 Hmong patients and 84 White controls, all of whom had ethnicity confirmed, an International Classification of Diseases, ninth revision code for gout and had at least 2 physician-documented diagnoses of gout. The Hmong group was younger (58.3 vs. 66.3 years, P = 0.04), had an earlier onset of symptoms (37.4 vs. 55.0 years, P < 0.001) and higher mean serum uric acid levels during follow-up (9.1 vs. 7.6 mg/dL, P ≤ 0.001). Hmong had higher rates of tophaceous gout (31.5% vs. 10.7%, P = 0.001), including hand tophi (21.3% vs. 3.6%, P < 0.001). In multivariable analyses that adjusted for age, sex, hypertension, diuretic, use, and kidney function, Hmong ethnicity was significantly associated with risk of tophaceous gout, with odds ratio 4.3 (95% confidence interval: 1.5, 12.2).
Conclusion: Hmong patients have an earlier onset of gout symptoms. Hmong race is an independent risk factor for tophaceous gout. Future studies need to examine whether genetic or other comorbid factors predict this higher risk of more severe gout in Hmong.