Hernandez, Brandy N.

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.

The objective of this project was to develop a standardized list of renally eliminated and potentially nephrotoxic drugs that will help inform initiatives to improve medication safety. Several available lists of medications from the published literature including original research articles and reviews, and from regulatory agencies, tertiary references, and clinical decision support systems were compiled, consolidated, and compared. Only systemically administered medications were included. Medication combinations were included if at least 1 active ingredient was considered renally dosed or potentially nephrotoxic. The medication list was reviewed for completeness and clinical appropriateness by a multidisciplinary team of individuals with expertise in critical care, nephrology, and pharmacy. An initial list of renally dosed and nephrotoxic drugs was created. After reconciliation and consensus from clinical experts, a standardized list of 681 drugs is proposed. The proposed evidence-based standardized list of renally dosed and potentially nephrotoxic drugs will be useful to harmonize epidemiologic and medication quality improvement studies. In addition, the list can be used for clinical purposes with surveillance in nephrotoxin stewardship programs. We suggest an iterative re-evaluation of the list with emerging literature and new medications on an approximately annual basis.