Hyperuricemia, gout, and cardiovascular disease--an important "muddle".

Multiple epidemiologic studies confrm an association between hyperuricemia and cardiovascular disease (CVD), but it remains uncertain whether hyperuricemia is an independent or dependent risk factor for CVD. The question is particularly complex since patients with gout frequently have multiple comorbid conditions and adjusting for these conditions tends to reduce the strength of hyperuricemia as a risk factor. In this article, we review the data supporting a possible independent role for hyperuricemia in CVD. A close reading of the literature suggests that hyperuricemia may be both an independent and dependent risk factor, and is more likely to act as an independent risk factor in blacks, women, and patients with high risk for CVD. We also review the literature that suggests that hyperuricemia may directly contribute to the development of a number of comorbid conditions that in turn contribute to CVD risk (e.g., hypertension, glucose intolerance, renal insuffciency, and adiposity), suggesting that adjusting studies for these risk factors may be biologically inappropriate. Finally, we review the limited literature addressing the question of whether gout per se, above and beyond the presence of hyperuricemia, may convey an additional independent CVD risk. Given the ready ability of physicians to pharmacologically manage serum urate levels, a better understanding of the interaction between hyperuricemia, gout and vascular disease may be critical for the reduction of morbidity and mortality in high-risk CVD patients.