[Relationship between severity of essential arterial hypertension and the prevalence hyperuricemia]

Hyperuricemia has been associated with an increased risk of cardiovascular disease in hypertensive patients. However, the relation between serum urate and severity of hypertension has not been conclusively defined as yet. We aimed at finding out whether there exists an independent relationship between changes in the prevalence of hyperuricemia and severity of hypertension.

We studied 3 cohorts of patients aged 35 to 60 years with essential hypertension diagnosed at a university hospital in Madrid, Spain. The first cohort (before 1981) included 325 patients, the second (from 1981 to 1989) comprised 271 patients and the third cohort (from 1990 to 1999) included 545 patients. Disease severity ranged from 1 to 6 according to blood pressure levels at diagnosis (WHO/ISH grades 1, 2 or 3 were assigned 1, 2 or 3 points, respectively) and target organ damage (left ventricular hypertrophy, hypertensive retinal vascular changes, and proteinuria above 300 mg/day; one point each).

Mean serum urate concentrations in the 3 cohorts were 6.6, 5.8 and 5.5 mg/dL, respectively (p < 0.05 for all comparisons). 39% of patients in the first cohort had a serum urate concentration > 7.0 mg/dL whereas only 18.1% patients in the third group showed hyperuricemia (difference: 20.9%; 95% CI, 10.1 to 32.3; p < 0.05). Severity of hypertension was higher in the first cohort (mean SD, 2.50 1.31 points) than in the third group (1.96 1.06 points; p < 0.05), with the second cohort showing an intermediate severity (2.23 1.01 points). Serum urate levels were directly related to the severity of hypertension in the 3 groups (r = 0.08, p < 0.05). In a multivariate analysis, after adjustment for confounding variables, serum urate had no significant association with severity of hypertension. However, target organ damage, systolic blood pressure and serum creatinine were all independent predictors of severity.

Favourable changes in the severity of hypertension for a time period significantly correlate with decreases in hyperuricemia prevalence in the same period. On the other hand, hyperuricemia appears to be an indirect marker of hypertensive renal damage.