Impact of kidney biopsy on the management of patients in the rheumatology department: retrospective study

Background. Kidney involvement is a common manifestation of the systemic autoimmune rheumatic diseases. Kidney biopsy is the gold standard for the diagnosis of kidney diseases, however this method has not yet become the standard-of-care in rheumatology practice. Aim. To assess the diagnostic value of kidney biopsy in the management of patients of the rheumatology department. Materials and methods. In this retrospective observational study we analyzed the medical documentation including kidney morphology findings in the patients of the Department of Rheumatology at Tareev Clinic of Internal Diseases. All patients included in the research had signs of kidney involvement and had undergone needle biopsy of the kidney or re-evaluation of the kidney tissue received previously. Results. From June 2016 to October 2021, 3110 patients were admitted to the rheumatology department. Among them 63 (2%) underwent kidney biopsy and were included in the study. Twenty (32%) were male. Mean age was 42.513.9 years. The most common preliminary diagnoses before kidney biopsy were ANCA-associated vasculitis (n=17), systemic lupus erythematosus (n=12), and AA-amyloidosis associated with inflammatory joint diseases (n=7). In 14 (27%) patients diagnosis was unspecified at the time of biopsy. Among 49 patients with established preliminary diagnosis morphological findings were in line 38 (78%) with the pre-liminary diagnosis. However, in 11 (22%) patients morphological findings resulted in the change of the diagnosis. In all 14 patients with unspecified condition kidney biopsy helped to establish clinical diagnosis. Ultrasound evaluation demonstrated hematoma formation in 18 (31%) patients, and among them two required blood component transfusions. Conclusion. Our study demonstrates significant value and safety of kidney biopsy in the patients with autoimmune rheumatic conditions. We suggest that kidney biopsy should be implemented in the management of this category of patients.