Percutaneous Kidney Biopsy and the Utilization of Blood Transfusion and Renal Angiography Among Hospitalized Adults

Abstract

Introduction: Data on percutaneous kidney biopsy (KBx) incidence and frequencies of hemorrhagic complications among inpatients are limited.

Methods: Using nationally representative US hospitalization discharge data, we report temporal trends in inpatient KBx rates from 2007 to 2014 and estimate frequencies of, and risk factors for, utilization of packed red blood cell (pRBC) transfusion and renal angiography.

Results: From 2007 to 2014, rates of native KBx among adult inpatients increased from 8.2 to 10.0 per 100,000, while transplant KBx rates declined from 3.6 to 3.1 per 100,000. We studied 35,183 and 14,266 discharge records with native and transplant KBx. We found that 5.7% (95% confidence interval [CI]: 5.3%-6.0%) of inpatients undergoing native KBx and 4.9% (4.2%-5.5%) of those undergoing transplant KBx received a pRBC transfusion within 2 days of biopsy. Similarly, 0.6% (0.5%-0.7%) of inpatients undergoing native KBx and 0.4% (0.2%-0.5%) undergoing transplant KBx received a renal angiogram within 2 days of KBx. For inpatient native KBx, female sex, older age, higher chronic kidney disease stage, acute renal failure, lupus, vasculitis, cirrhosis, multiple myeloma/paraproteinemia, and anemia of chronic disease were independently associated with increased odds of pRBC transfusion; cirrhosis and end-stage renal disease (ESRD) were associated with increased odds, and nephrotic syndrome was associated with decreased odds, of renal angiography.

Conclusions: In this large population-based study of inpatient KBx practices, we demonstrate increasing rates of inpatient native KBx among US adults and provide accurate estimates of the frequencies of, and risk factors for, pRBC transfusion and renal angiography following inpatient KBx.

Keywords: acute kidney injury; glomerular disease; renal biopsy.

Figure 1

Study cohort creation. All discharge records from the Nationwide Inpatient Sample (NIS) from 2007 to 2014 with a procedure code for percutaneous kidney biopsy (KBx) were included; records missing data on patients’ age, sex, mortal status at the time of discharge, and length of stay (LOS) were excluded, along with pediatric patients (aged <18 years). For analyses of packed red blood cell (pRBC) transfusions and renal angiography associated with KBx, we excluded discharge records that were missing data on the timing of KBx and the timing of pRBC transfusion/renal angiogram (where relevant), as well as discharge records in which KBx occurred before admission. Final cohorts represent data with complete information on the timing of KBx and pRBC transfusion/renal angiogram (where relevant).

Figure 2

Incidence estimates of native (black) and transplant (red) percutaneous renal biopsies (KBx) among inpatients in the United States, 2007 to 2014. Rates are per 100,000 population. The y-axes on the left of each panel correspond to native KBx (black), and y-axes on the right of each panel correspond to transplant KBx (red). P values for the trend over time are presented in the lower right-hand corner of each panel.

Figure 3

Rates of packed red blood cell (pRBC) transfusion and renal angiogram as a function of time from biopsy (days) among inpatients undergoing native kidney biopsy (KBx; black) and transplant KBx (red). (a, b) Cumulative proportions of patients receiving pRBC transfusion or renal angiogram as a function of days following KBx; only the first 2 days post-intervention are depicted here. Interventions occurring on the same day as KBx are considered “day 0” estimates.