ORLANDO — Hyperuricemia was an independent risk factor for the development of hypertension in a post hoc analysis of data collected on more than 3,000 men.
Future studies will need to address whether reducing a high serum level of uric acid is a safe and effective way to reduce a person's risk of developing hypertension, Dr. Eswar Krishnan said while presenting a poster at a conference on cardiovascular disease epidemiology and prevention sponsored by the American Heart Association.
The standard agent used to reduce hyperuricemia is allopurinol, a drug that's commonly used to treat patients with gout and a high uric acid level. If treatment of people with hyperuricemia with allopurinol could prevent the onset of hypertension, it would be an attractive option because allopurinol is cheap and is usually well tolerated except in a small percentage of people who are allergic to the drug, Dr. Krishnan said in an interview.
If a link between hyperuricemia and subsequent hypertension is confirmed, another way to apply the finding would be to advise people with hyperuricemia to take lifestyle steps to reduce their risk for hypertension, such as increased activity and weight loss, he said.
The study used data collected in the Multiple Risk Factor Intervention Trial (MRFIT), a study that enrolled nearly 13,000 men in the mid-1970s. The primary goal of MRFIT was to test the efficacy of a program of interventions aimed at cutting the risk of coronary heart disease in men who were at high risk for adverse coronary events (JAMA 1982;248:1465–77).
The analysis focused on the 3,073 men who were free from hypertension, metabolic syndrome, and diabetes at baseline, and for whom usable, baseline serum uric-acid levels were available. Men were followed for an average of 6 years, during which they had annual examinations. The probability that a man with a normal serum level of uric acid developed hyperuricemia at the next annual visit was 14%. The probability that a man with hyperuricemia would remain at an elevated level of serum uric acid at the next annual visit was 68%. For this analysis, hyperuricemia was defined as a serum uric acid level of more than 7.0 mg/dL; about a third of the men in the study had hyperuricemia at baseline.
During follow-up, 51% of the studied men (1,569) developed hypertension, defined as a systolic pressure of 140 mm Hg or greater or a diastolic pressure of 90 mm Hg or greater.
In a multivariate analysis that controlled for baseline differences in age, blood pressure, serum creatinine, total cholesterol, smoking, alcohol use, body mass index, proteinuria, and other potential confounders, men with hyperuricemia at baseline had an 81% increased risk of developing hypertension, a statistically significant difference, reported Dr. Krishnan, a rheumatologist at the University of Pittsburgh. For every 1 mg/dL increase in the serum level of uric acid at baseline, the risk of developing hypertension during follow-up increased by 9%, also a statistically significant difference.