Background The extended 2016 EULAR updated report states that for patients on ULT, SUA level should be monitored and maintained to <6 mg/dL (360 µmol/L). SUA level <3 mg/dL (180 µmol/L) is not recommended in the long term. And among EULAR proposals for future research is mentioned the optimal duration for prophylaxis of acute attacks when starting ULT, long-term impact of very low urate levels on the central nervous system, impact of ULT on kidney function.

Objectives This project aims to investigate the impact of two target levels urate-lowering therapy (ULT) caused by hyperuricemia (HU) on kidney function and CKD progression measured by eGFR and albuminuria (A).

This trial had been formulated by 2016 updated EULAR evidence-based recommendations for the management of gout as a perspective proposal task for future research.

The key points are: 1) an unknown target HU level and 2) the time duration of ULT resulting in preserved kidney function in two subject groups a) with gout and b) without gout but highly elevated uricemia and CKD.

Methods The trial has POEM design with 36 months duration. IMPULsKF is a Clinical Randomised Prospective Controlled Open Multicenter trial that randomly (by chance) assigns 180 participants in parallel groups. These patients with high SUA level (>8 mg/dL; 480 µmol/L) were divided into 2 arms (90+90) 1) with gout (EULAR’s criteria) and 2) without gout but with presence of CKD 1–4) and 2 target SUA levels in each group as 5 mg/dL (300 µmol/L) and ultralow SUA <3 mg/dL (180 µmol/L) achieved either with allopurinol or febuxostat. The data obtained will be compared with control group (45 with gout without CKD and 45 with CKD).

Results Retrospective analysis and 6 mothes in trial results has been shown that treatment with febuxostat improves GFR and BP control in patients with asymptomatic HU in non-diabetic CKD 2–3.²

Febuxostat treatment led to the most beneficial decrease in the level of uric acid (−223±16 µmol/l, p≤0,01 with control and p≤0,05 with allopurinol group), increased GFR (+10±2 ml/min, p≤0,01 with control and p≤0,05 with allopurinol group), blood pressure decrease (- 7±2/–3±1 mm hg, p≤0,05 with control and p=0,93 with allopurinol group), albuminuria (−131±19 mg, p≤0,01 with control and p≤0,05 with allopurinol group. Potential benefits of febuxostat were better tolerability compared with allopurinol group with target levels of uricemia less 180 µmol/l in 32% of people.

Conclusions Treatment with febuxostat (better than allopurinol) improves GFR and BP in patients with asymptomatic hyperuricemia in non-diabetic CKD 2–3. Ultralow SUA levels seems to be safe in majority of patients but its effect on CKD function is not yet clear.

References [1] Richette P, Doherty M, Pascual E, Barskova V, Becce Fet al,2016updated EULAR evidence-based recommendations for the management of gout. Ann Rheum Dis2017 Jan;76(1):29–42. doi:10.1136/annrheumdis-2016–209707. Epub 2016 Jul 25. http://dx.doi.org/10.1136/annrheumdis-2016-209707

[2] Ivanov D, Ivanova M. SP 326 Febuxostat improves GFR and BP in non-diabetic adults with CKD 2–3: 4 years follo-up. NDT 2015 V30 S 3 pp486-7

Disclosure of Interest None declared