Estimated GFR With Cystatin C and Creatinine in Clinical Practice: A Retrospective Cohort StudyPlain-Language Summary

Rationale &amp; Objective: Estimation of glomerular filtration rate (eGFR) and staging of chronic kidney disease (CKD) are essential to guide management. Although creatinine is routinely used, a recent national task force recommended the use of cystatin C for confirmation. The objective of this study was to examine the following parameters: (1) how cystatin C correlates with creatinine eGFR; (2) how it indicates differences in CKD staging; and (3) how it may affect kidney care delivery. Study Design: Retrospective observational cohort study. Setting &amp; Participants: 1,783 inpatients and outpatients who had cystatin C and creatinine levels drawn within 24 hours at Brigham Health-affiliated clinical laboratories. Predictors: Serum creatinine levels, basic clinical/sociodemographic variables, and reasons for ordering cystatin C from a structured partial chart review. Analytical Approach: Univariate and multivariable linear and logistic regression. Results: Cystatin C-based eGFR was very strongly correlated with creatinine-based eGFR (Spearman correlation ρ = 0.83). Cystatin C eGFR resulted in a change to a later CKD stage in 27%, an earlier stage in 7%, and no change in 66% of patients. Black race was associated with a lower likelihood of change to a later stage (OR, 0.53; 95% CI [0.36, 0.75]; P < 0.001), whereas age (OR per year OR, 1.03; 95% CI [1.02, 1.04]; P < 0.001) and Elixhauser score (OR per point OR, 1.22; 95% CI [1.10, 1.36]; P < 0.001) were associated with a higher likelihood of change to a later stage. Limitations: Single center, no direct measurement of clearance for comparison, and inconsistent self-identification of race/ethnicity. Conclusions: Cystatin C eGFR correlates strongly with creatinine eGFR but can have a substantial effect on CKD staging. As cystatin C is adopted, clinicians must be informed on this impact

Excessive diagnostic testing in acute kidney injury

Background: The patterns, performance characteristics, and yield of diagnostic tests ordered for the evaluation of acute kidney injury (AKI) have not been rigorously evaluated. Methods: We characterized the frequency of AKI diagnostic testing for urine, blood, radiology, and pathology tests in all adult inpatients who were admitted with or developed AKI (N = 4903 patients with 5731 AKI episodes) during a single calendar year. We assessed the frequency of abnormal test results overall and by AKI stage. We manually reviewed electronic medical records to evaluate the diagnostic yield of selected urine, blood, and radiology tests. Diagnostic yield of urine and blood tests was determined based on whether an abnormal test affected AKI diagnosis or management, whereas diagnostic yield of radiology tests was based on whether an abnormal test resulted in a procedural intervention. In sensitivity analyses we also evaluated appropriateness of testing using prespecified criteria. Results: Frequency of testing increased with higher AKI stage for nearly all diagnostic tests, whereas frequency of detecting an abnormal result increased for some, but not all, tests. Frequency of detecting an abnormal result was highly variable across tests, ranging from 0 % for anti-glomerular basement membrane testing to 71 % for urine protein testing. Many of the tests evaluated had low diagnostic yield. In particular, selected urine and blood tests were unlikely to impact AKI diagnosis or management, whereas radiology tests had greater clinical utility. Conclusions: In patients with AKI, many of the diagnostic tests performed, even when positive or abnormal, may have limited clinical utility

Non-tunneled versus tunneled dialysis catheters for acute kidney injury requiring renal replacement therapy: a prospective cohort study

Background: Acute kidney injury requiring renal replacement therapy (AKI-RRT) is associated with high morbidity, mortality and resource utilization. The type of vascular access placed for AKI-RRT is an important decision, for which there is a lack of evidence-based guidelines. Methods: We conducted a prospective cohort study over a 16-month period with 154 patients initiated on AKI-RRT via either a non-tunneled dialysis catheter (NTDC) or a tunneled dialysis catheter (TDC) at an academic hospital. We compared differences in renal replacement delivery and mechanical and infectious outcomes between NTDCs and TDCs. Results: Patients who received TDCs had significantly better RRT delivery, both with continuous venovenous hemofiltration (CVVH) and intermittent hemodialysis (IHD), compared to patients who received NTDCs; these findings were confirmed after multivariable adjustment for AKI-specific disease severity score, history of chronic kidney disease, renal consult team, and AKI cause. In CVVH and IHD, the median venous and arterial blood flow pressures were significantly higher with TDCs compared to NTDCs (p < 0.001). Additionally for CVVH, the median number of interruptions per catheter was higher with NTDCs compared to TDCs (Rate Ratio (RR) 2.7; p < 0.001), and for IHD, a higher median blood flow was seen with TDCs (p < 0.001). There were a significantly higher number of mechanical complications with NTDCs (RR 13.6 p = 0.001). No significant difference was observed between TDCs and NTDCs for positive blood cultures per catheter. Conclusions: Compared to NTDCs, TDCs for patients with AKI-RRT had improved RRT delivery and fewer mechanical complications. Initial TDC placement for AKI-RRT should be considered when not clinically contraindicated given the potential for improved RRT delivery and outcomes. Electronic supplementary material The online version of this article (10.1186/s12882-017-0760-x) contains supplementary material, which is available to authorized users

Keys to Driving Implementation of the New Kidney Care Models

Contemporary nephrology practice is heavily weighted toward in-center hemodialysis, reflective of decisions on infrastructure and personnel in response to decades of policy. The Advancing American Kidney Health initiative seeks to transform care for patients and providers. Under the initiative\u27s framework, the Center for Medicare and Medicaid Innovation has launched two new care models that align patient choice with provider incentives. The mandatory ESRD Treatment Choices model requires participation by all nephrology practices in designated Hospital Referral Regions, randomly selecting 30% of all Hospital Referral Regions across the United States for participation, with the remaining Hospital Referral Regions serving as controls. The voluntary Kidney Care Choices model offers alternative payment programs open to nephrology practices throughout the country. To help organize implementation of the models, we developed Driver Diagrams that serve as blueprints to identify structures, processes, and norms, and generate intervention concepts. We focused on two goals that are directly applicable to nephrology practices and central to the incentive structure of the ESRD Treatment Choices and Kidney Care Choices: () increasing utilization of home dialysis, and () increasing the number of kidney transplants. Several recurring themes became apparent with implementation. Multiple stakeholders from assorted backgrounds are needed. Communication with primary care providers will facilitate timely referrals, education, and comanagement. Nephrology providers (nephrologists, nursing, dialysis organizations, others) must lead implementation. Patient engagement at nearly every step will help achieve the aims of the models. Advocacy with federal and state regulatory agencies will be crucial to expanding home dialysis and transplantation access. Although the models hold promise to improve choices and outcomes for many patients, we must be vigilant that they not do reinforce existing disparities in health care or widen known racial, socioeconomic, or geographic gaps. The Advancing American Kidney Health initiative has the potential to usher in a new era of value-based care for nephrology