Percutaneous kidney biopsy trends in the Medicare population by specialty from 2011 to 2021: implications for nephrology training requirements and radiology referral patterns.

PURPOSE: To study trends in volume and reimbursement for percutaneous kidney biopsy (PKB) by physicians and advanced practice providers (APPs) for Medicare enrollees from 2011-2021. METHODS: Claims from the Medicare Part B Physician/Supplier Procedure Master File (a national Medicare database) for 2011-2021 were extracted using Current Procedural Terminology codes for PKB. Total volumes were compared by provider specialty. Non-facility reimbursement, work Relative Value Unit (RVU) non-facility practice expense RVU, and malpractice RVU were compared. RESULTS: Between 2011 and 2021, total volume of PKB by physicians and APPs increased from 30,753 to 34,090 (10.9%), with a peak of 37,882 in 2019 prior to the COVID 19 pandemic. Radiology performed the majority of procedures during the study period. Relative share for radiology increased from 67.6% to 81.1% while the relative share for internal medicine/nephrology decreased from 24.3% to 14.3%, accelerating between 2019 and 2020. Volume and relative share for APPs marginally increased (from 0.9% to 1.2%). Non-facility reimbursement decreased from $578.96 in 2010 to $568.76 in 2021 (1.7%), work RVU decreased from 2.63 to 2.38 (9.5%), non-facility practice expense RVU decreased from 14.10 to 13.71 (2.8%), and malpractice RVU decreased from 0.31 to 0.21 (32.3%). CONCLUSION: Volume and total share of PKB performed by radiology increased over the study period. Conversely, internal medicine/nephrology performed fewer kidney biopsies. Despite the expanding role for APPs in other image-guided procedures, very few PKBs were performed by APPs throughout the study period. Reimbursement and RVU for PKB declined over the study period.

Choroidal Vascularity Index versus Choroidal Thickness as Biomarkers of Acute Central Serous Chorioretinopathy.

INTRODUCTION: The aim of this study was to analyze the choroidal vascularity index (CVI) versus choroidal thickness (CT) as biomarkers in acute central serous chorioretinopathy (CSCR). METHODS: In this multicenter retrospective, cross-sectional, noninterventional study carried out at Puerta de Hierro-Majadahonda University Hospital, Madrid, Spain; Jules-Gonin, Lausanne, Switzerland; and Pittsburg University, USA. 40 eyes from 40 patients with acute CSCR, 40 eyes from 40 patients with keratoconus (KC), and 40 eyes from 40 healthy patients were included. The variables analyzed were age, CT, CVI, and the presence of neurosensory retinal detachment. CT and the CVI were obtained from a 12-mm horizontal single-line B-scan (Triton SS-OCT, Topcon Co., Japan). Blinded measurements of the subfoveal CT were performed manually by two independent investigators. The images of the choroid were automatically binarized using a validated algorithm, and a percentage of vascularity was calculated. RESULTS: There were no significant differences in age between the three groups (ANOVA, p = 0.092). There were statistically significant differences in CT and the CVI (ANOVA, p < 0.001). After Bonferroni correction, pairwise analysis between CSCR group against the KC group showed no significant differences in age and CT (p = 0.10 and p = 0.27, respectively). CVI was statistically greater among CSCR patients (p = 0.03). CONCLUSION: CT does not meet the criteria to be considered a biomarker of acute CSCR, while CVI may prove to be a more specific and reliable biomarker. Further studies with larger sample sizes, standardized procedures, and a wider representation of all CSCR stages are necessary to confirm the validity of CVI as biomarker in this disease. Further studies with larger samples are required in order to validate the use of CVI/CT correlation as a new biomarker.