The relationship of body mass index and hyperuricemia in hypertensive adults over 80 years

Background Hyperuricemia （HUA） and hypertension are associated with the increasing risk and mortality of cardiovascular disease （CVD）. However, the relationship between body mass index （BMI） and HUA in hypertensive adults over 80 years remains uncertain. Methods Observational trial was designed and 308 patients who were newly diagnosed as essential hypertension without anti-hypertensive therapy were enrolled into our study. According to the cut-off value of serum UA, participants were stratified into normal （ 〈420μmol/L for men and 〈360 μmol/L for women） and increased UA groups （≥420 μmol/L for men and ≥360 μmol/L for women）. Serum UA level, blood pressure and other baseline characteristics were compared, logistic regression analysis and receiver operating characteristic curve （ROC） were performed. Results The mean（SD） serum uric level was 382.2 （108.7） μmol/L and the prevalence of hyperuricemia was 45% among men and 50% among women. BMI was significantly higher （22.6 vs. 24.0 kg/m^2, P=0.003） and FBG was lower （5.13 vs. 4.98 mmol/L, P=0.025） in increased UA group among aged women, and BMI and FBG were found the independent determinants for UA increase in female subjects according to logistic regression analysis, and the odd ratio were 1.154（95% interval confidence 1.058- 1.259, P=0.001） and 0.646 （95% interval confidence 0.44-0.949, P=0.026） , respectively. Moreover, evaluation of receiver operating characteristic curve （ROC）showed that area under the curve for BMI to predict UA increase was 0.627±0.039, P=0.001 in women. However, the results mentioned above were only found in elderly women, not in men. Conclusions Our study indicates that aged women have higher prevalence of HUA than men, and that BMI is independently associated with serum uric acid level for hypertensive women but not for men over 80 years old. Therefore, BMI is a useful predictor of serum uric acid level in el- derly women with hypertension.