Significance of determination of kidney of tubular biomarker KIM-1 in children with juvenile idiopathic arthritis

Abstract

Renal tubular lesions play an important role in the development and progression of chronic kidney disease (CKD). There has been only one cohort retrospective study of the prevalence of CКD in children with juvenile idiopathic arthritis (JIA). Therefore, early diagnosis of kidney damage using renal biomarkers is important.

Purpose - to determine the frequency and risk factors for the development of structural tubular lesions by studying the level of kidney injury molecule-1 (KIM-1) in the urine of children with JIA, depending on the characteristics of the clinical course of the disease, use of nonsteroidal anti-inflammatory drugs (NSAIDs).

Materials and methods. 80 children from JIA were examined. To measure the marker KIM-1 in urine samples, an enzyme-linked immunosorbent assay was used.

Results. The indicator of the urinary marker KIM-1 in the examined children was 0.997±0.1662 (0.98; 0.90-1.12) ng/ml. High activity of JIA affects the level of urinary KIM-1 - among children with high activity of the disease, 20% had a high level of KIM-1. Involvement of ≥6 joints almost 3-fold increased the in CIdence of elevated urinary KIM-1 levels (OR=5.00; 95% CI: 1.65-15.15; p<0.006). Risk factors for structural tubular kidney lesions in children with JIA were identified: high JIA activity (OR=7.25; 95% CI: 1.22-43.22; p<0.04), arthritis ≥6 joints (OR=5.00; 95% CI: 1.65-15.15; p<0.006), arthritis of the small joints of the hands (OR=4.85; 95% CI: 1.39-16.87; p<0.02), arthritis of the wrist joints (OR=3.78; 95% CI: 1.21-11.83; p<0.03), arthritis of the hip joints (OR=10.41; 95% CI: 1.02-106.7; p<0.05). The level of urinary biomarker KIM-1 was negatively affected by long-term use of NSAIDs (ρ=0.60, p<0.004). An increased level of KIM-1 in urine is associated with hypertension (OR=12.43; 95% CI: 2.26-68.27; p<0.003) and reduced Estimated Glomerular Filtration Rate (eGFR) according to the Hoek formula (OR=15.58; 95% CI: 4.02-60.36; p<0.001), which suggests the presence of CKD in children with JIA as a result of tubular lesions.

Conclusions. Structural damage of the renal tubules, which was established by studying the biomarker KIM-1 in the urine and the relationship with reduced eGFR according to the Hoek formula, suggests the presence of CKD in children with JIA as a result of tubular lesions. Urine KIM-1 testing should be included in the JIA screening plan for early diagnosis of renal disease.

The study was carried out in accordance with the principles of the Helsinki Declaration. The study protocol was approved by the Local Ethics Committee of the institution specified in the work. Informed consent was obtained from the parents of the children for the research.

The authors declare no conflicts of interest.