Read your latest personalised notifications
No account yet? Start here
Don't miss out
Ok, got it
Dr. Luis Ruilope
Dr. César Cerezo
Investigating the potential role of urate reduction in the cardiorenal disease, especially using urate-lowering agents is currently under way. Antihypertensive drugs can, however, modify the development of gout events in hypertensive patients, with losartan and calcium channel blockers having the greatest lowering effect on blood pressure because of their uricosuric properties. We present an up-to-date review of literature on the relationship of uric acid and kidney disease, cardiovascular disease and hypertension, with the recommendations that ensue.
Hyperuricemia is defined as serum urate levels above 6.5 mg/dl, and it is well known that patients with higher levels are at increased risk of developing gout arthropathy, both acute arthritis or chronic tophaceus gout, uric acid urolithiasis and gouty nephropathy. As urate-lowering agents are limited in number and effectiveness, allopurinol, a xanthine oxidase inhibitor, is the most commonly prescribed agent even with the fact that its utilization is limited due to its albeit uncommon, but potentially severe side effects (1). Febuxostat, a non–purine analogue inhibitor of xanthine oxidase, is used for the management of hyperuricemia in patients with gout, - as it has shown fewer adverse events in subjects with renal dysfunction when compared with allopurinol (2). In the last decades there has been a reappraisal of the relationship between elevated urate serum levels and an increased risk of hypertension, other vascular risk factors and cardiovascular (CV) and renal disease (3-7).
Discovery of uric acid happened in the 1700’s with the analysis of a bladder stone. Sir Archibald Edward Garrod first established a relationship between hyperuricemia and osteoarthritis only a century later, in the 1800’s. Gout linked with chronic kidney disease was considered from the beginning. In fact, the condition defined as “gouty nephropathy” was originally attributed to the deposition of urate crystals in the tubules and renal interstitium heading to a local inflammatory reaction (9). Data since has shown an association between increased uric acid levels and diminished renal blood flow, without variations in estimated glomerular filtration rate, and with increased renal and peripheral resistances. This would explain why the expression “gout nephropathy” has been abandoned and local crystal deposit have no longer been thought to be the reason for renal damage. Rather, kidney harm is believed to reflect prompt renovascular involvement owing to chronic hypertensive or age-related glomerulosclerosis (10), especially among subjects with essential hypertension. As a consequence and as of yet:
A relationship between hyperuricemia and CV disease has been established since the 1900's. Increased uric acid serum levels are a common finding in patients with high blood pressure, insulin resistance, obesity and CV disease. Furthermore, uric acid as a CV risk factor has been addressed in numerous prospective and cohort studies (12). Nevertheless, debate arose from early times as to whether uric acid is an independent predictor of CV disease or not. It was later proven that both renal vasoconstriction and various CV drugs - principally renin-angiotenin system suppressors and insulin- were associated with reduced urate excretion, further studies showed that it was more accurate to regard hyperuricemia as a consequence of the existence of previously related CV risk factors (10). Yet, some theories were that increased uric acid levels would be good based on antioxidant properties (13), and positive outcomes on endothelial function were shown following the infusion of uric acid. On the other hand, an increase in blood pressure and increased salt sensitivity, stimulation of the renin-angioten system, and the development of insulin resistance, would all have been beneficial in certain situations, such as tissue injury and ischemia. This controversy caused uric acid to be no longer regarded as a true CV risk factor (14). With increased awareness of the function of uric acid in cardiorenal disease, discussion has resurfaced in the last years. Epidemiological studies have revealed that uric acid concentrations predict the progression of chronic kidney disease (7) the development of stroke (5), and a recent meta-analysis reported that uric acid is associated with the presence of hypertension (3), diabetes (4), and metabolic syndrome (15). Relationship between coronary artery disease and uric acid, however, remains controversial. Another recent meta-analyses studying the relationship between uric acid and CHD showed that serum uric acid levels are not likely to be a main determinant of CHD and may not contribute significantly to the prediction of CHD in the general population (6). Nonetheless, the debate cannot be complete since conflicting information has put forward that uric acid could be a prognostic marker of CV events including myocardial infarction, heart failure, stroke and death (16). Finally, in patients with heart failure there is significant confirmation that elevated uric acid levels predict an increase in morbidity and mortality both in acute and chronic heart failure patients (17). Recent evidence has emerged in parallel suggesting uric acid is an inflammatory factor that also plays a role in endothelial dysfunction. Thus, uric acid can induce proinflammatory changes in the adipocyte that are similar to those observed in the prediabetic subject (18). Finally, most of these trials suggested that uric acid’s cardiorenal effects are due to its intracellular effects (1), unlike gout and stones. Therefore, practical conclusions regarding that relationship are that:
The relationship between uric acid and arterial hypertension was originally described in the early 60s, when prospective studies revealed that 26% of untreated hypertensive patients with normal renal function had elevated plasma uric acid levels. This outline increased to 58% for those receiving antihypertensive drugs, and it was principally high in those taking diuretics (70%)(20). As well, elevated uric acid levels in all subjects, both normotensive and hypertensive alike, have been related to a damaged vascular situation in the kidney usually due to atherosclerosis (10). On the other hand, there is rising support that hyperuricemia, at least in certain populations, stimulates the onset of hypertension through the generation of an inflammatory cascade, where endothelial dysfunction, smooth muscle proliferation and development of renal afferent arteriolosclerosis appear. Moreover, hypertension is one of the most common comorbidities of gout, affecting up to 74% of patients with gout arthropathy, as described in the most recent estimations from the US National Health and Nutrition Examination Survey (2007-8). In addition, high blood pressure levels are independently associated with incident gout (3), due to the reduced renal blood flow added to both elevated renal and systemic vascular resistance, together with decreased renal excretion of urate. Certain antihypertensive drugs can, as it is well known, modify the development of gout events in hypertensive patients, by increasing the levels of uric acid, - diuretics and betablockers especially. A recent case-control study evaluated, among a hypertensive cohort, the associations of different antihypertensive drugs with the risk of episodes of gout (8). The UK general practice database was used and 24 768 patients with newly diagnosed gout and 50 000 randomly controls among individuals between 20-79 years of age between the years 2000 and 2007 were included. The use of calcium channel blockers and losartan was associated with a significantly reduced risk of incident gout (relative risk 0.87, 95% confidence interval 0,82 to 0,93; 0,81, 0,70 to 0,94, respectively); the reduced urate levels due to an increased renal excretion of urate could explain this effect. On the other hand, diuretics, betablockers, angiotensin converting enzyme inhibitors, and non-losartan angiotensin receptor blockers were associated with a notably enlarged probability of gout. Interestingly, comparable outcomes were established in normotensive patients. Therefore, it has been suggested that:
Conclusion: Evidence regarding the relationship between high serum uric acid concentrations and hypertension and other cardiovascular risk factors is extensive. Furthermore, current data also suggest that hyperuricemia could increase the risk of developing renal and CV disease. Nevertheless, it is too early to make clinical recommendations in regard to the benefits of using xanthine oxidase inhibitor allopurinol or the novel febuxostat in patients with asymptomatic increased uric acid levels and high CV risk. Further studies are needed to assess the exact role of uric acid reduction in the progression of cardiorenal events. Antihypertensive drugs can, however, modify the development of gout events in hypertensive patients, with losartan and calcium channel blockers having the greatest lowering effect on blood pressure because of their uricosuric properties.
1. Schlesinger N. Management of acute and chronic gouty arthritis: present state-of-the-art. Drugs 2004;64:2399-2416 2. Becker M. Febuxostat Compared with Allopurinol in Patients with Hyperuricemia and Gout. N Engl J Med 2005; 353:2450-2461 3. Grayson PC, Kim SY, Lavalley M, Choi HK. Hyperuricemia and incident hypertension: a systematic review and meta-analysis. Arthritis Care Res (Hoboken). 2011;63:102-10. 4. Kodama S, Saito K, Yachi Y, Asumi M, Sugawara A, Totsuka K, et al. Association between serum uric acid and development of type 2 diabetes. Diabetes Care. 2009;32:1737-42. 5. Kim SY, Guevara JP, Kim KM, Choi HK, Heitjan DF, Albert DA. Hyperuricemia and risk of stroke: a systematic review and meta-analysis. Arthritis Rheum. 2009;61:885-92. 6. Wheeler JG, Juzwishin KD, Eiriksdottir G, Gudnason V, Danesh J. Serum uric acid and coronary heart disease in 9,458 incident cases and 155,084 controls: prospective study and meta-analysis. PLoS Med. 2005;2:e76. 7. Kang DH, Nakagawa T, Feng L, Watanabe S, Han L, Mazzali M, et al. A role for uric acid in the progression of renal disease. J Am Soc Nephrol. 2002;13:2888-97. 8. Choi HK, Soriano LC, Zhang Y, Rodríguez LAG. Antihypertensive drugs and risk of incident gout among patients with hypertension: population based case-control study. BMJ 2012;344:d8190. 9. Talbott JH, Terplan KL. The kidney in gout. Medicine (Baltimore). 1960;39:405-67. 10. Messerli FH, Frohlich ED, Dreslinski GR, Suarez DH, Aristimuno GG. Serum uric acid in essential hipertension: an indicator of renal vascular involvement. Ann Intern Med 1980;93:817-21. 11. Weiner DE, Tighiouart H, Elsayed EF, Griffith JL, Salem DN, Levey AS. Uric acid and incident kidney disease in the community. J Am Soc Nephrol 2008;19:2004-11. 12. Rakic MT, Valkenburg HA, Davidson RT, Engels JP, Mikkelsen WM, Neel JV, et al. Observations on the natural history of hyperuricemia and gout. I. An eighteen year follow-up of nineteen gouty families. Am J Med. 1964;37:862-71. 13. Nieto FJ, Iribarren C, Gross MD, Comstock GW, Cutler RG. Uric acid and serum antioxidant capacity: a reaction to atherosclerosis? Atherosclerosis. 2000;148:131-9. 14. Culleton BF. Uric acid and cardiovascular disease: a renal-cardiac relationship? Curr Opin Nephrol Hypertens. 2001;10:371-5. 15. Nakagawa T, Hu H, Zharikov S, Tuttle KR, Short RA, Glusha- kova O, et al. A causal role for uric acid in fructose-induced metabolic syndrome. Am J Physiol. 2006;290:F625-31. 16. Strasak AM, Kelleher CC, Brant LJ, et al. VHM&PP study group. Serum uric acid is an independent predictor for all major forms of cardiovascular death in 28,613 elderly women: a prospective 21-year follow-up study. Int J Cardiol. 2008;125:232-9. http://www.ncbi.nlm.nih.gov/pubmed/18237790 17. Thanassoulis G, Brophy JM, Richard H, Pilote L. Gout, allopurinol use, and heart failure outcomes. Arch Intern Med. 2010;170: 1358-64. 18. Sautin YY, Nakagawa T, Zharikov S, Johnson RJ. Adverse effects of the classic antioxidant uric acid in adipocytes: NADPH oxidase-mediated oxidative/nitrosative stress. Am J Physiol Cell Physiol. 2007;293:C584-96. 19. Goicoechea M, de Vinuesa SG, Verdalles U, Ruiz-Caro C, Ampuero J, Rincon A, et al. Effect of allopurinol in chronic kidney disease progression and cardiovascular risk. Clin J Am Soc Nephrol 2010;5:1388-93. 20. Cannon PJ, Stason WB, Demartini FE, Sommers SC, Laragh JH. Hyperuricemia in primary and renal hypertension. N Engl J Med 1966;275:457-64. 21. Holeggen A, Alderman MH, Kjeldsen SE, Julius S, Devereux RB, De Faire U, et al. The impact of serum uric acid on cardiovascular outcomes in LIFE study. Kidney Int 2004;65:1041-9. 22. Miao Y, Ottenbros SA, Laverman GD, Brenner BM, Cooper ME, Parving HH, et al. Effect of a reduction in uric acid on renal outcomes during losartan treatment: a post-hoc analysis of the reduction of end-points in non-insulin-dependent diabetes mellitus with the angiotensin II antagonist losartan trial. Hypertension 2011;58:2-7
Correspondence: César Cerezo Hypertension Unit. Hospital 12 de Octubre Av. Córdoba s/n 28041 Madrid. Spain. T: 34913908198 F: 34913908035 E: email@example.com Authors discosures: None declared.
Our mission: To reduce the burden of cardiovascular disease
© 2018 European Society of Cardiology. All rights reserved