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Kidney biopsy is essential for the diagnosis and treatment of several kidney diseases. However, in the elderly, the benefits and risks must be carefully considered due to potential complications and frailty associated with age. The elderly patient usually has a lower physiological reserve and is more prone to complications. The aim of our study was to evaluate the characteristics of patients >65y compared to those <65y, analyze the complications associated with the procedure, and establish whether age is a risk factor for major complications.
Retrospective, descriptive, observational, multicenter study from January 2022 to 2023; performed at the Interventional Nephrology Clinic of the Instituto Nacional de Cardiologia Ignacio Chavez, in Mexico and the Hospital Italiano de Buenos Aires, in Argentina.
The comparison of continuous variables was performed with the Mann-Whitney-Wilcoxon U test, and categorical variables were analyzed with the Pearson Chi-Square test.
807 patients were included, divided into two groups; 703 (87.2%) <65y and 104 (12.8%) >65y. The average age in the elderly group was 72y. 77% of the biopsies performed in the elderly were in native kidneys. The pre-biopsy systolic blood pressure in the elderly was higher (p <0.001) [SBP 138 vs 130 mmHg], the BUN in the elderly was 68 vs 51 mg/dL. The kidney biopsy technique in the elderly was 76% with a longitudinal approach and 24% with a transversal approach.
Complications occurred in 18.7% (132) of those < 65y, while in the elderly, they occurred in 21.1% (22) (p=0.628). The most frequent complications in the elderly were hematoma 17.3% (18) and hematuria 3.8% (4). 78.9% (82) of patients did not have complications (p=0.612).
Histological diagnoses were as follows: Amyloidosis 16.4%, AAV 14.5%, MN 12.7%, TIN 10.9%, FSGS 9%, Other 9.1%, MPGN 7.3%, DN 5.5%, IgAN 5.5%, MGRS 3.6%, LN 1.8%, MCD 1.8% and TMA 1.8%. Interstitial fibrosis was <25% in 32.2%, 25-50% 52.2% and >50% in 15.6%. Treatment was modified in 51.9% of patients.
In our study, there were no major complications in those >65y compared to <65y (p=0.628). The complications are those described in the general population. Kidney biopsy in the elderly should be performed after careful evaluation of risks and benefits. Decision-making must be individualized, considering the general health, frailty, and specific risk factors of each patient.