Dear Editor,
In the recent issue of your journal, we were grateful to read an interesting article by Aribaş et al. (Citation1) demonstrating that uric acid is an independent determinant of erectile dysfunction, irrespective of blood pressure control with antihypertensive medications such as beta-blockers and thiazide-type diuretics.
Serum uric acid is associated with endothelial dysfunction, oxidative stress and inflammation, and is now beginning to be considered a risk predictor for cardiovascular diseases (Citation2,Citation3). Erectile dysfunction is a common disease characterized by endothelial dysfunction, and uric acid itself causes endothelial dysfunction via decreased nitric oxide production and decreased vasodilator response to acetylcholine (Citation4,Citation5). Elevated uric acid levels in hypertensive patients were only attributed to anti-hypertensive medications before now; however, today it is known that, irrespective of medical therapy, uric acid levels are elevated in hypertensive patients. In parallel to this, Aribas et al. (Citation1) showed that uric acid levels in patients using thiazide-like diuretics were higher compared with non-users (6.30 ± 1.5 vs 5.5 ± 1.5 mg/dl, p = 0.05); however, in multiple logistic regression analysis, only age [odds ratio, OR = 1.08; 95% confidence interval, CI 1.04–1.14), p = 0.001], smoking [OR = 2.33; 95% CI 1.05–5.20), p = 0.04] and uric acid [OR = 1.76; 95% CI 1.28–2.41, p = 0.04] were found to be independent determinants of erectile dysfunction. Beta-blockers and thiazide-like diuretics did not reach statistical significance in the regression model. Similarly, in a recent study, Salem et al. (Citation6) showed that uric acid levels were significantly higher in hypertensive patients with erectile dysfunction than in a control group (6.12 ± 1.55 and 4.97 ± 1.09 mg/dl, respectively; p < 0.001). However, they did not mention medications of patients.
Aribas et al. (Citation1) found the prevalence of erectile dysfunction to be 55% in their study, which is comparable with the current literature. They included patients using at least one antihypertensive drug for at least 1 year in the study. However, it would be better if they studied uric acid levels and its relation to erectile dysfunction in patients with recently diagnosed hypertension without using medical therapy. Although beta-blockers and diuretic therapy did not reach statistical significance in regression analysis, they showed that uric acid levels were higher in patients taking these drugs.
As a conclusion, elevated uric acid levels lead to endothelial dysfunction, which may further cause erectile dysfunction in hypertensive patients. The present study indicates that uric acid is increased in hypertensive patients with erectile dysfunction independently from antihypertensive medications. However, the study should be interpreted with the limitations mentioned above and larger studies are needed to clarify the definitive mechanisms of erectile dysfunction in these subjects.
Declaration of interest: The authors report no conflicts of interest. The authors alone are responsible for the content and writing of the paper.
References
- Aribas A, Kayrak M, Ulucan S, Keser A, Demir K, Alibasic H, et al. The relationship between uric acid and erectile dysfunction in hypertensive subjects. Blood Press. 2014;23:370–376.
- Feig DI, Kang DH, Johnson RJ. Uric acid and cardiovascular risk. N Engl J Med. 2008;359:1811–1821.
- Lyngdoh T, Marques-Vidal P, Paccaud F, Preisig M, Waeber G, Bochud M, et al. Elevated serum uric acid is associated with high circulating inflammatory cytokines in the population-based Colaus study. PLoS ONE. 2011;6:e19901.
- Park JH, Jin YM, Hwang S, Cho DH, Kang DH, Jo I. Uric acid attenuates nitric oxide production by decreasing the interaction between endothelial nitric oxide synthase and calmodulin in human umbilical vein endothelial cells. A mechanism for uric acid-induced cardiovascular disease development. Nitric Oxide. 2013;32:36–42.
- Matheus AS, Tibirica E, da Silva PB, de Fatima Bevilacqua da Matta M, Gomes MB. Uric acid levels are associated with microvascular endothelial dysfunction in patients with type 1 diabetes. Diabet Med. 2011;28:1188–1193.
- Salem, S, Mehrsai, A, Heydari, R, Pourmand, G. Serum uric acid as a risk predictor for erectile dysfunction. J Sex Med. 2014;11:1118–1124.