Background: the number of patients with progressive chronic kidney disease (CKD) and the costs of their treatment is constantly increasing. Possibly, control of serum uric acid (sUA) levels with urate lowering therapy (ULT) drugs can slow the progression of kidney function deterioration.

Objectives: to determine the efficacy and safety of allopurinol and febuxostat in treatment of patients with CKD to reduce the level of sUA and to analyze the effect of such treatment on glomerular filtration rate (GFR).

Methods: the study included 45 patients with CKD (stages 3b-5). Patients with recent acute kidney injury, acute glomerulonephritis, advanced heart failure, with kidney transplant, other severe/decompensated diseases; contraindications to the use of allopurinol/febuxostat – were not included. The target level of sUA for patients with pre-dialysis stages of CKD was set at 300 µmol/l, for patients on hemodialysis target was not set.

All patients underwent a comprehensive clinical and laboratory examination, laboratory tests (full blood count, creatinine, sUA, ALT, AST, GFR calculation (CKD- EPI). All patients were divided into one of the study groups for the treatment of HU: Group I (28 patients, 61,3±3,2 y.o., CKD3b-12, CKD4-10, on hemodialysis-6 patients) received febuxostat (40-120 mg/day), Group II (24 patients, 60,7±4,1y.o., CKD3b-9, CKD4-10, on hemodialysis -5 patients) took allopurinol (50-300 mg/day – for patients with pre-dialysis CKD and up to 800 mg/day - for patients on hemodialysis). Clinical and laboratory examination was repeated after 1, 3 and 6 months; sUA levels were determined with individual frequency, with correction of of ULT drugs doses, taking into account GFR (for allopurinol).

Results: The majority of participants showed a significant decrease in the level of sUA under the influence of ULT drugs, however, the achievement of the target level of sUA was significantly more often registered in Group I: after 1 month – in 45.5% (in group II – in 15.9%, p<0.001); after 3 months - in 67.5% (in group II - 21.2% p<0.01); after 6 months, these figures were 90% and 37.1%, respectively (p<0.01). The achievement of sUA levels of less than 300 µmol/l was accompanied by significant positive GFR dynamics in most patients (in 90% of patients, GFR increased compared with the baseline, on average - in group I - by 3.1±0.51 ml/min, while in group II there was a gradual progression of GFR deterioration - in 31.8% of patients.

During the study period, no serious adverse events (AE) were noted in study patients, mild and moderate adverse events (totally - 8 events) were registered in 5 patients (2 patients took febuxostat and 3 - allopurinol). Development of AEs did not lead to the discontinuation in study participation in any cases, but made impossible to increase the dose of allopurinol in 3 patients.

Conclusion: In patients with pre-dialysis stages of CKD, the use of febuxostat is accompanied by stabilization or increase in GFR. Use of febuxostat in patients with CKD stage 3b-4 and in patients on hemodialysis is safe and more effective for target sUA level achievement than the use of allopurinol.

Disclosure of Interests: None declared