REN and kidney disorder: In Goicoechea’s study, after 24 months, in the control group, eGFR decreased 3.3 ± 1.2 mL/min per 1.73 m2, and in the allopurinol group, eGFR increased 1.3 ± 1.3 mL/min per 1.73 m2, so that, allopurinol treatment slowed down renal disease progression independently of age, gender, diabetes, C-reactive protein, albuminuria, and renin-angiotensin system blockers use [10].