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 at a conference on cardiovascular disease epidemiology and prevention sponsored by the American Heart Association.
The standard agent used to reduce hyperuricemia is allopurinol. 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 for 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.
The study used data collected in the Multiple Risk Factor Intervention Trial (MRFIT), which enrolled nearly 13,000 men in the mid-1970s. Its primary goal 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.
The analysis focused on the 3,073 men who were free from hypertension, metabolic syndrome, and diabetes at baseline, and for whom usable baseline uric-acid levels were available. Men were followed in the MRFIT for an average of 6 years, during which they had annual examinations. The probability that a man with a normal level of uric acid developed hyperuricemia (serum uric acid level > 7.0 mg/dL) at the next annual visit was 14%. The probability that a man with hyperuricemia would remain at an elevated level of uric acid at the next annual visit was 68%. 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 at least 140 mm Hg or a diastolic pressure of at least 90 mm Hg.
In a multivariate analysis that controlled for baseline differences in age, blood pressure, serum creatinine, total cholesterol, smoking, alcohol use, BMI, 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 level of uric acid at baseline, the risk of developing hypertension during follow-up increased by 9%, also a significant difference.