Relation of serum uric acid and body mass index to mortality in high-risk patients with established coronary artery disease: a report from the ET-CHD registry, 1997-2006

BACKGROUND

Hyperuricemia is associated with a higher risk of death in patients with coronary artery disease (CAD). In contrast, overweight or obesity was associated with survival benefits in this population. However, the relation of body mass index (BMI) and serum uric acid (SUA) to mortality has not been clarified in this population.

METHODS

We studied a cohort of 1202 patients with angiographic CAD from the ET-CHD registry during 1997-2003 in Taiwan. To evaluate the relation of BMI and SUA on mortality, the subjects were categorized into 4 groups by BMI >/= 25 kg/m(2) (overweight or obesity) or BMI<25 kg/m(2) (normal- or under-weight), and SUA levels higher or lower than the median of 6.6 mg/dl. At a median follow-up of 5.4 years, cardiac and all-cause deaths were the primary end points.

RESULTS

Multivariate analyses demonstrated that high SUA group had a significantly higher cardiac mortality [hazard ratio (HR): 1.79, 95% confidence interval (CI): 1.14-2.82, p=0.023] and overall mortality (HR: 1.68, 95% CI: 1.19-2.36, p=0.003) than low SUA group only in overweight or obese patients. Additionally, high BMI was associated with a significantly lower cardiac mortality (HR: 0.58, 95% CI: 0.38-0.99, p=0.023) and overall mortality (HR: 0.62, 95% CI: 0.41-0.82, p=0.003) than low BMI in patients with low SUA levels. Furthermore, normal-low weight and underweight patients (BMI<21 kg/m(2)) were found to have a higher risk of mortality regardless of SUA levels.

CONCLUSIONS

Among patients with established CAD, SUA may be a potent predictor to mortality in overweight or obese patients. Moreover, the obesity-mortality paradox phenomenon was mainly driven by higher mortality risk in underweight patients and lower mortality risk in overweight and obese patients with low SUA.

Gender differences in the impact of diabetes on mortality in patients with established coronary artery disease: a report from the eastern Taiwan integrated health care delivery system of Coronary Heart Disease (ET-CHD) registry, 1997-2006

OBJECTIVES

The effect of type 2 diabetes mellitus (DM) on mortality was more pronounced in women than men with coronary artery disease (CAD) in the pre-stent era before 1996. However this relationship is controversial in the post-stent era.

METHODS

We studied a cohort of 1073 patients with angiographically defined CAD from the Eastern Taiwan integrated health care delivery system of Coronary Heart Disease (ET-CHD) registry during 1997-2003 in Tzu-Chi General Hospital, Hualien, Taiwan. To evaluate gender-specific DM effect on mortality, the subjects were divided into 4 groups: diabetic women (n=147), non-diabetic women (n=127), diabetic men (n=239), and non-diabetic men (n=560). At a mean follow-up of 5.4 years, cardiac and all-cause mortality were the primary end points.

RESULTS

Annual total mortality rates were 10.2%, 5.1%, 7.2%, and 4.8%; annual cardiac mortality rates were 8.2%, 3.0%, 4.3%, and 2.6% for diabetic women, non-diabetic women, diabetic men, and non-diabetic men, respectively. Multivariate Cox regression models, adjusted for possible confounders showed that gender-specific hazard ratios (HRs) of DM for total mortality were 2.02 (95% CI: 1.32-3.09), and 1.72 (95% CI: 1.32-2.25) for women and men, respectively. The HRs for total mortality associated with diabetes were not different between women and men (p=0.53). Similarly, adjusted gender-specific HRs of DM for cardiac mortality were 2.46 (95% CI: 1.45-4.19) for women, and 1.83 (95% CI: 1.28-2.62) for men, which were also not significantly different (p=0.36).

CONCLUSIONS

Among patients with CAD, the impact of DM on mortality was consistently higher in women than in men, but the differences across sexes were not statistically significant after 1996 in Taiwan.

Serum uric acid as an independent predictor of mortality in high-risk patients with obstructive coronary artery disease: a prospective observational cohort study from the ET-CHD registry, 1997-2003

BACKGROUND

Serum uric acid (SUA) has been observed to be highly associated with the development of cardiovascular disease for more than 50 years. Several studies have reported elevated SUA as an independent predictor of mortality in patients with coronary artery disease (CAD) after adjustment for classic risk factors but some studies did not find similar results.

METHODS

Between January 1997 and December 2003, a prospective cohort study was performed in 1054 patients with angiographically defined CAD, and their classic risk factors and SUA levels were determined at enrollment. The study cohort was followed for an average of 3.2 years, with a median of 3.1 years. The main outcome measure was death from cardiac disease and any cause.

RESULTS

Of all study patients, 789 (74.9%) were men and 265 (25.1%) were women. The mean age of the male and female patients was 64.8 and 66.9 years, respectively. The mean SUA level of all patients was 410.4 μmol/L. There were grading effects of SUA quartiles on cardiac and all-cause mortality in univariate and multivariate Cox regression analyses. After adjustment, the multivariate analyses revealed that patients in the highest SUA quartile (>487 μmol/L) had 2.08 (95% CI=1.19-3.62, p=0.01) fold increased risk of cardiac death, and 1.68 (95% CI=1.10-2.57, p=0.017) fold increase risk of overall mortality compared with the lowest quartile (<315 μmol/L).

CONCLUSIONS

SUA may be a significant predictor of cardiac and overall mortality, independent of classic risk factors in high-risk patients with obstructive CAD.