We read with interest the article by Stack et al.1 We are concerned by the statement “No clinically meaningful changes were observed in estimated glomerular filtration rate [eGFR] or serum creatinine or serum cystatin C concentrations.” Participants in the verinurad and febuxostat group lost 8.1 mL/min/1.73 m2 in eGFR from baseline to follow-up (of up to 28 weeks)—that is, they lost 13% of baseline eGFR; meanwhile, patients in the placebo group remained stable (baseline and follow-up values of 68.1 and 68.0 mL/min/1.73 m2, respectively).