Association of Kidney Biopsy Needle Gauge with Postprocedure Complications and Biopsy Adequacy

Key Points Needle selection in kidney biopsy requires balancing risk of complications with benefit of obtaining diagnostic tissue. Our data show that higher needle gauge provides more tissue for diagnosis but might be associated with greater risk of complications. Background While a larger needle gauge can provide additional kidney tissue for diagnosis, it might also predispose to greater complication risk. Here, we evaluate the safety and diagnostic adequacy of kidney biopsies in patients who underwent a biopsy with various needle sizes. Methods We evaluated rates of biopsy-related complications and adequacy between participants who underwent biopsy with 16 versus 18 G needles. We assessed safety using a composite outcome of blood transfusion, angiographic intervention, hemoglobin drop of at least 2 g/dl, or at least a medium sized hematoma after kidney biopsy. We defined adequacy as the number of glomeruli available for diagnosis. Results Among 781 participants included in the analysis, 665 biopsies (85%) were performed using a 16 G needle and 116 (15%) were performed using an 18 G needle. We observed similar odds of complications in the 16 G group as compared with the 18 G group in univariable analysis (odds ratio, 1.56 [95% confidence interval, 0.81 to 3.01]); however, there were higher odds of complications in the 16 G group in both multivariable analysis adjusting for prebiopsy bleeding risk factors (2.40 [1.16 to 4.93]) and propensity score weighted analysis (2.92 [1.28 to 6.67]). As compared with 18 G needle, 16 G biopsy needle was associated with more glomeruli obtained (13 [9–19] versus 11 [6–15], P < 0.001). The higher number of glomeruli in 16 G group persisted after multivariable adjustment (5.06 [2.52 to 7.59]) and propensity score weighted (4.39 [0.37 to 8.42]) analyses. Conclusions Participants with kidney biopsies performed with a 16 G needle tended to sample more glomeruli and had similar complications on univariable analysis but higher complications when adjusting for prebiopsy risk factors. This indicates that larger needle gauge provided more tissue for diagnosis, but clinicians appropriately avoided its use in those at higher risk of complications. Our findings suggest that the use of a 16 G needle improves diagnostic yield but carries a higher adjusted risk of complications, underscoring the importance of individualized needle gauge selection.