ABSTRACT

Corresponding Author:
Dr. Shruthi S,
Flat No. 610, Meridian Apartments Near,
Gardenia Hostel Laxmigudda,
Nithyananda Nagar Post,
Mangalore-575018.
E-mail: shuthibhat@gmail.com

ABSTRACT

BACKGROUND

Few studies have assessed the relation of hyperuricemia with the severity of Coronary Artery Disease (CAD). This study investigated the association between high uric acid levels with the presence and severity of CAD.

MATERIALS AND METHODS

Fifty patients having angiographic evidence of atherosclerosis (CAD+case group) compared to 50 patients with no luminal stenosis (n=) or with <50% luminal stenosis (n=) at coronary angiography (CAD-control group).

RESULTS

The mean age of the patients was 60±10 years (317 men, 58.7%). Hyperuricemia was more likely associated with a trend toward higher vessel scores indicating a more severe CAD (adjusted OR=1.51, 95% CI=1.09-2.09; P=0.005) in the whole population.

CONCLUSION

Asymptomatic hyperuricemia was associated with the presence and severity of angiographically-defined CAD in patients with suspicious symptoms for CAD.

KEYWORDS

Uric Acid, CAD, Angiography.

INTRODUCTION

Coronary heart disease is a worldwide health epidemic. Although, age-specific events related to CHD have fallen dramatically in the last few decades. The overall prevalence has risen as population, age and patients survive the initial coronary or cardiovascular event. Worldwide, 30 percent of all deaths can be attributed to cardiovascular disease of which more than half are caused by CHD (coronary heart disease) and the forecasts for the future estimate a growing number as a consequence of lifestyle changes in developing countries.

Globally, of those dying from cardiovascular diseases, 80 percent are in developing countries and not in the western world. Global Burden of Disease (GBD) study reported that in 1990 there were 5.2 million deaths from cardiovascular diseases in economically developed countries and 9.1 million deaths from the same causes in developing countries.¹

The prevalence of coronary artery disease in India has increased from 1 percent in 1960 to 9.7 percent in 1995 in urban populations and in rural populations it has almost doubled in the last decade.²Coronary artery disease has a

In CAD+group, 93 percent of patients had chest pain, 28 percent breathlessness, 6 percent palpitations and 10 percent had associated other symptoms. Among male patients, 27 (93.1%), 11 (37.9%), 2 (6.9%), 3 (10.3%) had chest pain, breathlessness, palpitations and had associated with other symptoms, respectively. Among females in CAD+group, 18 (85.7%), 3 (14.3%), 1 (4.8%), 2 (9.5%) had above symptoms respectively. In CAD-group, 45 (90%) patients had chest pain, 14 (28%) had breathlessness, 3 (6%) palpitation and 5 (10%) other symptoms.

50 (100.0%) patients had hyperuricemia in CAD+group and 3 (6.0%) in CAD-group. 29 (100%) and 21 (100.0%) were females in CAD+group.

Only 3 (14.3%) in CAD-group had hyperuricemia who were all females, which was statistically significant as shown in the above Tables II, IIIA and B and Graph I, both males and females.

In CAD+group, mean uric acid level was 7.46±0.636 mg% with males having 7.76±0.579 mg% and females having 7.048±0.463 mg%, which was statistically significant as shown in Table IIIA (p value <0.001).

In CAD-group, mean uric acid level was 4.094±0.993 mg% with males having 4.15±0.922 mg% and Females having 4.023±1.094 mg% was statistically significant as shown in the Table IIIB (p value<0.001).

Mean uric acid level in all patients according to severity of CAD was found to be 7.09±0.219 mg% in minimal, 7.32±0.626 mg% in mild, 7.40±0.485 mg% in moderate, 7.70±0.763 mg% in severe category respectively, which was statistically significant (p value <0.001) as shown in the above Table VI.

Mean uric acid level in male patients according to severity of CAD was found to be 7.12±0.217 mg%, 7.60±0.235 mg%, 7.60±0.502 mg%, 8.30±0.427 mg% in minimal, mild, moderate, severe category of CAD, respectively. This is statistically significant as shown in above Table VI.

Mean uric acid level in female patients according to severity of CAD was found to be 7.00±0.283 mg%, 6.98±0.826 mg%, 7.04±0.089 mg%, 7.09±0.482 mg% in minimal, mild, moderate, severe form of CAD.

DISCUSSION

In our study of investigating 100 patients undergoing coronary angiography, we found that hyperuricemia was associated with the presence of angiographically documented CAD in the whole population in men and women individually, and that this association was independent of other confounding cardiovascular risk factors. Moreover, we found that patients with hyperuricemia showed independently a trend to more severe CAD scaled by vessel score.

Fang and colleagues in the NHANES I epidemiologic followup study on a representative sample of the United States adult population showed that increased levels of serum uric acid are related to increased cardiovascular morbidity and mortality.³ Madsen and colleagues suggested that in patients with significant CAD (stenosis ≥70% in coronary angiography), high levels of serum uric acid could be a strong risk factor for adverse outcome and mortality.⁴

Our findings add to the growing body of evidence that hyperuricemia is independently associated with the development of CAD. Despite this, because of complex interrelationships of uric acid levels with many other established cardiovascular risk factors such as metabolic syndrome, obesity, diabetes and chronic renal disease.^5,6,7

In a Tuttle and colleagues study, there was also a linear correlation between uric acid levels and CAD severity in women, but not in men.⁸ Recently, Jelic-Ivanovic and colleagues compared the levels of uric acid in 356 patients with significant coronary lesion (≥50%) as a case group with 350 people in a control group (coronary luminal narrowing <50%). After adjusting for confounders, they found differences between the uric acid concentrations in the case vs. control group only in women; no significant differences were observed in men with or without significant coronary lesions in their study.⁹

Persky et al studied, the association between uric acid and the prevalence of ECG abnormalities and with mortality appear to be secondary to associations between uric acid and other risk factors in men.¹⁰ Gur M, Yilmaz R, Demirbag R et al studied relation of serum uric acid levels with the presence of angiographic coronary artery disease.¹¹ Some studies have found association of serum uric acid with ischaemic heart disease and hypertension.¹²

Li Qin†, Zhen Yang †, Hongxia Gu, Shuai Luet et al studied association between serum uric acid levels and cardiovascular disease in middle-aged and elderly Chinese individuals and concluded that elevated serum uric acid level was associated with cardiovascular disease, independent of conventional cardiovascular disease risk factors and metabolic syndrome.¹³

In our study, the independent adjusted association of hyperuricemia with the severity of CAD was investigated in patients having normal coronary arteries, minimal CAD, 1-vessel, 2-vessel and 3-vessel disease. In our study, patients with smoking history, elevated BMI, hyperlipidaemia with elevated triglyceride, LDL, total cholesterol, elevated fasting blood sugar levels, hyperuricemia was associated with CAD + group.

CONCLUSION

Our total hyperuricemia study population was independently associated with angiographically documented CAD. Additionally, in multiple regressions, CAD severity in all and in men and women was independently related to hyperuricemia. Our findings suggest that asymptomatic hyperuricemia has an independent role in cardiovascular disease. Asymptomatic hyperuricemia was associated with the presence and severity of angiographically-defined CAD in patients with suspicious symptoms for CAD.