Background: Juvenile idiopathic arthritis (JIA) is a chronic disease requiring years of therapy with non-steroidal anti-inflammatory drugs (NSAIDs), immunosuppressant’s, cytostatics, immunobiological agents. The aforementioned drugs, namely NSAIDs and cytostatics are potentially nephrotoxic [1]. The above drugs, namely NSAIDs and cytostatics, are potentially nephrotoxic. About 8% of children with JIA have kidney damage, which develops on average 5 years after the onset of the disease. It has been established that the main risk factor for the development of kidney damage is the long-term exposure to NSAIDs and methotrexate in children with active forms of JIA [2]. Early diagnosis of kidney damage will allow timely correction in the dosage of drugs and avoid their nephrotoxic effects [3].

Objectives: To determine the effect of drug therapy in children with JIA on eGFR by using the Cystatin C-based equation and the Hoek formula based on the serum cystatin C study.

Methods: 80 children with JIA participated in the study. The age of subjects was 10.4±4.41 (10.6-15.0) years. All children received methotrexate as a base drug. At the moment of examination 22 children received NSAIDs, 25 children received immunobiological preparations. Serum cystatin C content was determined by enzyme immunoassay.

The Cystatin C-based equation 2012 and Hoek formulas were used to set the GFR by serum cystatin C levels.

Results: Non-steroidal anti-inflammatory drugs led to a decrease in GFR as found by both the Cystatin C-based equation 2012 and the Hoek formula. The incidence of GFR reduction in patients treated with NSAIDs using the Cystatin C-based equation 2012 was 100%, and using the Hoek formula was 81.8%.

The use of NSAIDs in children with JIA is a risk factor for the development of reduced GFR calculated by the Hoek formula. The incidence of reduced GFR in children with NSAID use was 54.5%, 6.7 times greater than in those without NSAIDs (OR = 12.9; CI: 3.76-44.25; p<0.001). There was a low chance of a Hoek formula decrease in GFR in children with JIA who received immunobiological therapy 9.1% vs 46.8% (OR = 0.11; CI: 0.03-0.42; p<0.001).

Conclusion: Use of NSAIDs in children with JIA was more often associated with a reduction in GFR: by Cystatin C - based equation 2012 in 100% of cases p<0.01, by Hoek in 81.8%, p<0.001. The average of GFR was significantly lower in children treated with NSAIDs than in children without NSAIDs. Immunobiological therapy had a positive effect on the GFR value. The frequency of a decrease in GFR was significantly lower in the children treated with immunobiological therapy compared with those without immunobiological therapy 9.1% vs 46.8% (OR = 0.11; CI: 0.03-0.42; p<0.001).

REFERENCES:

[1]Giancane G, Alongi A, Ravelli A. Update on the pathogenesis and treatment of juvenile idiopathic arthritis. Curr Opin Rheumatol. 2017 Sep;29(5):523-529. doi: 10.1097/BOR.0000000000000417.

[2]Giancane G, Alongi A, Ravelli A. Update on the pathogenesis and treatment of juvenile idiopathic arthritis. Curr Opin Rheumatol. 2017 Sep;29(5):523-529. doi: 10.1097/BOR.0000000000000417.

[3]Ebert N, Bevc S, Bökenkamp A, et al. Assessment of kidney function: clinical indications for measured GFR. Clin Kidney J.2021;14(8):1861-1870.doi: 10.1093/ckj/sfab042.

Disclosure of Interests: None declared