Reply to Letter to the Editor From Professor Viroj Wiwanitkit,Bankok,Thailand

Abstract

We thank Prof Wiwanitkit for his questions.¹ Following are the differences between our study and the previous report.² The characteristics of our study population were based on the average age of 69.6 years and the overall prevalence of hyperuricemia was 24.9% (males 26.5% and females 23.5%).³ They were different from the patients with the average age of 45 years and low prevalence of hyperuricemia (overall 8.3%, males 12.5%, and females 2.5%) in the previous study.² Additionally, the relation of serum uric acid (SUA) with target organ damage was analyzed as each 1.1 mg/dL increase (ie, 1 standard deviation) owing to relatively low prevalence of hyperuricemia in the previous report.² In contrast, our study³ found that the highest quartile of SUA concentration and hyperuricemia had an independent association with peripheral artery disease, which was not assessed in previous report.² According to our research,³ we could not conclude that SUA was absolutely not associated with subclinical vascular damage.

For the urine spot collection, microalbuminuria is influenced by variation in urinary volume, and higher albumin concentration when urine is more concentrated and vice versa. So it is preferable to use the albumin–creatinine ratio (ACR) to correct the variations in urinary volume. There is no difference between the 24-hour urinary albumin concentration and the ACR in their ability to estimate microalbuminuria.⁴ Considering the burden and costs in population screening for microalbuminuria, measurement of the ACR in spot urine has many advantages and is recommended by guidelines.^5,6

References

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. Serum uric acid concentration and asymptomatic hyperuricaemia. Angiology. 2014;65(7):641.

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. Lack of association between serum uric acid and organ damage in a never-treated essential hypertensive population at low prevalence of hyperuricemia. Am J Hypertens. 2007;20(6):678–685.

. Serum uric acid concentration and asymptomatic hyperuricemia with subclinical organ damage in general population. Angiology. 2014;65(7):634–640.

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. The validity of screening based on spot morning urine samples to detect subjects with microalbuminuria in the general population. Kidney Int Suppl. 2005;(94):S28–S35.

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. Proteinuria and other markers of chronic kidney disease: a position statement of the national kidney foundation (NKF) and the national institute of diabetes and digestive and kidney diseases (NIDDK). Am J Kidney Dis. 2003;42(4):617–622.

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; for the National Kidney Disease Education Program-IFCC Working Group on Standardization of Albumin in Urine. Current issues in measurement and reporting of urinary albumin excretion. Clin Chem. 2009;55(1):24–38.