Teaford, Hilary R.

AbstractBackgroundAccurately estimating glomerular filtration rate (GFR) is crucial for dosing medications in hospitalized patients. Due to limitations of serum creatinine for GFR estimation, serum cystatin C (CysC) has been explored as an alternative functional kidney biomarker. This study assessed discordance between eGFRCr and eGFRCysC in a large sample of hospitalized patients and examined the frequency of renally eliminated medications affected by eGFR discordance.MethodsThis multisite historical study included adults hospitalized between 2011 and 2023 with CysC and serum creatinine reported within 24 h of each other. The first concurrent biomarker pair for each patient was analyzed. eGFR discordance and use of renally eliminated medications were described.Results17,718 hospitalized patients with concurrent creatinine and CysC assessments were included. The median eGFRCr was 65 mL/min, and the eGFRCysC was 46 mL/min. The median absolute difference of eGFRCr−eGFRCysC was 15 mL/min, and 7972 patients (45%) had a > 30% absolute difference. There was a significantly greater percentage of patients with an eGFR <30 mL/min based on eGFRCysC (26%) compared to eGFRCr (15%) (p < 0.001). Patients were prescribed an average of 20 medications in the 24 h surrounding the concurrent biomarker assessment. Renally eliminated medications accounted for 39% ± 13% of medication orders, and 80% of patients with eGFR discordance were prescribed five or more renally eliminated medications.ConclusionSubstantial eGFR discordance between eGFRCysC and eGFRCr was observed in hospitalized patients, which directly affects the dosing of renally eliminated medications. Further research is needed to optimize the pharmacotherapy of renally eliminated medications with discordant GFR assessments to improve medication safety and effectiveness.

Abstract Purpose With the implementation of a new electronic health record (EHR) system across Mayo Clinic, a project was approved to standardize and converge 9 region-specific large-volume infusion pump (LVP) drug libraries for Baxter SIGMA Spectrum pumps. Summary The objectives of the project were to (1) develop recommendations for identified variances in practice, (2) consolidate regional drug libraries into a converged enterprise library, (3) improve the drug library management process, and (4) maintain or exceed previous Dose Error Reduction System (DERS) compliance for infusions administered. Harmonization efforts with infusion pumps decreased the number of drug libraries maintained, reduced content maintenance time, and increased readiness for smart infusion pump–EHR interoperability. Seven of the 8 regions for which change in DERS compliance was assessed showed improved compliance relative to baseline in the 30-day postwashout period. Furthermore, when comparing pre- and postimplementation DERS compliance, the number of regions meeting the minimum compliance rate of 95% increased from 5 to 6 regions. Conclusion The project improved the drug library management process, allowed for DERS compliance to be accurately compared across regions, and ensured that patients across the enterprise receive the same standard of care with the administration of intravenous medications.

The use of the kidney function biomarker cystatin C (cysC) can improve the accuracy of vancomycin dosing for target trough attainment in nonobese patients. It is unknown whether cysC can also improve vancomycin target trough attainment in overweight and obese patients. We conducted a retrospective observational study of overweight or obese hospitalized adults with stable renal function administered intravenous vancomycin between January 2011 and July 2019. Linear regression models were used to predict initial steady-state vancomycin troughs using several factors, including various cysC- and serum creatinine (SCr)-based estimates of kidney function.

Pharmacists are at the forefront of dosing and monitoring medications eliminated by or toxic to the kidney. To evaluate the effectiveness and safety of these medications, accurate measurement of kidney function is paramount. The mainstay of kidney assessment for drug dosing and monitoring is serum creatinine (SCr)-based estimation equations. Yet, SCr has known limitations including its insensitivity to underlying changes in kidney function and the numerous non-kidney factors that are incompletely accounted for in equations to estimate glomerular filtration rate (eGFR). Serum cystatin C (cysC) is a biomarker that can serve as an adjunct or alternative to SCr to evaluate kidney function for drug dosing. Pharmacists must be educated about the strengths and limitations of cysC prior to applying it to medication management. Not all patient populations have been studied and some evaluations demonstrated large variations in the relationship between cysC and GFR. Use of eGFR equations incorporating cysC should be reserved for drug management in scenarios with demonstrated outcomes, including to improve pharmacodynamic target attainment for antibiotics or reduce drug toxicity. This article provides an overview of cysC, discusses evidence around its use in medication dosing and in special populations, and describes practical considerations for application and implementation.