LAUSR

To the Editor, We have read the research article “Uric acid-lowering and renoprotective effects of topiroxostat, a selective xanthine oxidoreductase inhibitor, in patients with diabetic nephropathy and hyperuricemia: a randomized, double-blind, placebo-controlled, parallel-group study (UPWARD study)” by Wada et al. [1], the authors presented comparative study results of topiroxostat and placebo in patients with diabetic nephropathy and hyperuricemia. We would like to request the authors to clarify or elucidate the following points for further understanding. First, the authors stated that all patients screened (n = 141) were with diabetic nephropathy and gout or hyperuricemia. However, Table 1 mentioned as number of patients with type 2 diabetes mellitus (T2DM) in the placebo group n = 21 out of n = 22 and in topiroxostat as n = 42 out of n = 43, respectively. Hence, patients without T2DM should be excluded from the data analysis set. Second, at baseline, the values of eGFR in placebo and topiroxostat are 68.3 ± 21.7 and 66.3 ± 17.6 ml/min/1.73 m2, respectively. Based on these values, we can consider them as normal patients, since the eGFR value is more than 60 ml/ min/1.73 m2 instead of compromised patients [2]. Third, in Fig. 2 in the placebo group, the number of patients completed as per criteria mentioned is 18; however, as per protocol, analysis stated as 19 and number of protocol violation 1. Considering this, the number of patients as per protocol criteria should have been 17, but 19 is considered for calculation. We would be highly obliged for your kind consideration of the above-mentioned clarifications in your article to understand more beneficial effects of a selective xanthine oxidoreductase inhibitor, i.e., topiroxostat in patients with diabetic nephropathy and gout or hyperuricemia.