Discordance of renal drug dosing using estimated creatinine clearance and measured urine creatinine clearance in hospitalized adults: A retrospective cohort study

Performance of different body weights in the Cockcroft-Gault equation in critically ill patients with and without augmented renal clearance: A multicenter cohort

STUDY OBJECTIVE

The primary objective was to evaluate the performance of the Cockcroft-Gault (CG) equation with different body weights (BWs) compared to a measured creatinine clearance (mCrCl) in an intensive care unit (ICU) population with and without augmented renal clearance (ARC).

DESIGN

Multicenter, retrospective cohort.

SETTING

Two ICUs in the United States and four ICUs from a previous international observational analysis.

PATIENTS

Adult ICU patients admitted from January 1, 2010 to July 30, 2020 with at least one mCrCl collected within the initial 10 days of hospitalization were eligible for inclusion.

MEASUREMENTS AND MAIN RESULTS

The primary outcome was the performance of the CG equation in ARC (mCrCl≥130 ml/min/1.73 m2 ) and non-ARC (mCrCl<130 ml/min/1.73 m2 ) patients. Correlation was analyzed by Pearson's correlation coefficient, bias by mean difference, and accuracy by the percentage of patients within 30% of the mCrCl. A total of 383 patients were included, which provided 1708 mCrCl values. The majority were male (n = 239, 62%), median age of 55 years [IQR 40-65] with a surgical diagnosis (n = 239, 77%). ARC was identified in 229 (60%) patients. The ARC group had lower Scr values (0.6 [0.5-0.7] vs. 0.7 [0.6-0.9] mg/dl, p < 0.001) and higher mCrCl (172.8 (SD 39.1) vs. 89.9 mL/min/1.73 m2 (SD 25.4), p < 0.001) compared with the non-ARC group, respectively. Among non-ARC patients there was a moderate correlation (r = 0.33-0.39), moderate accuracy (range 48-58%), and low bias (range of -12.9 to 17.1) among the different BW estimations with the adjusted BW having the better performance. Among ARC patients there was low correlation (r = 0.24-0.28), low to moderate accuracy (range 38-70%), and high bias (range of -58.5 to -21.6).

CONCLUSIONS

The CG-adjusted BW had the best performance in the non-ARC patients, while CG performed poorly with any BW in ARC patients. Although the CG equation remains the standard equation for estimating CrCl in the ICU setting, a new, validated equation is needed for patients with ARC.

Prevalence and Risk Factors of Augmented Renal Clearance: A Systematic Review and Meta-Analysis

Kidney function assessment in the critically ill overlooks the possibility for hyperfunctioning kidneys, known as augmented renal clearance (ARC), which could contribute to therapeutic failures in the intensive care unit (ICU). The aim of this research is to conduct a systematic review and meta-analysis of prevalence and risk factors of ARC in the critically ill. MEDLINE, Embase, Cochrane Library, CINAHL, Scopus, ProQuest Dissertations and Theses Global databases were searched on 27 October 2020. We included studies conducted in critically ill adults who reported the prevalence and/or risk factors of ARC. We evaluated study quality using the Joanna Briggs Institute appraisal tool. Case reports, reviews, editorials and commentaries were excluded. We generated a random-effects meta-analytic model using the inverse variance method and visualized the pooled estimates using forest plots. Seventy studies were included. The pooled prevalence (95% CI) was 39% (34.9–43.3). Prevalence for neuro, trauma, mixed and sepsis ICUs were 74 (55–87), 58 (48–67), 36 (31–41) and 33 (21–48), respectively. Age, male sex and trauma were associated with ARC with pooled OR (95% CI) of 0.95 (0.93–0.96), 2.36 (1.28–4.36), 2.60 (1.21–5.58), respectively. Limitations included variations in ARC definition, inclusion and exclusion criteria and studies design. In conclusion, ARC is prevalent in critically ill patients, especially those in the neurocritical care and trauma ICU population. Young age, male sex and trauma are risk factors for ARC in those with apparently normal renal function. Further research on optimal dosing of drugs in the setting of ARC is warranted. (Prospero registration: CRD42021246417).

Correlation of Measured and Estimated Creatinine Clearance in Hospitalized Elderly Patients: A Retrospective Cohort Study

Background: Accurate assessment of renal function is essential in hospitalized elderly patients. Few studies have examined the accuracy of Cockcroft-Gault (C-G) estimates of creatinine clearance (CrCl) compared with measured clearance in these patients. Objective: The objective of this study was to determine the correlation between C-G estimates of CrCl and measured CrCl in hospitalized elderly patients. Methods: This Institutional Review Board-approved, single-center retrospective observational cohort study included all patients who were 65 years and older admitted to our medical center in January to September 2018 with either an 8- or 24-hour urine collected during admission. The primary outcome was correlation, bias, and precision of C-G estimates of CrCl versus measured CrCl using Pearson correlation, Spearman linear regression, and Bland-Altman analysis. Outliers were determined using a cut-off of ±20%. Data are presented as median (interquartile range) or percentages. Results: A total of 108 urine collections from 90 unique patients were included in the study. The patients were 51% female, median age was 71 (68-77) years, and median body mass index was 26.6 (22.8-31) kg/m². Most collections were over 24 hours (66.7%), and 38% were performed while patients were in an intensive care unit. Median blood urea nitrogen (BUN) was 24.5 (17-36) mg/dL and median serum creatinine was 0.71 (0.55-1.09) mg/dL. The median C-G estimation was 75.4 (48.2-110.6) mL/min, and the median measured CrCl was 79.1 (38.1-99.5) mL/min, r ² = .56 (P < .001). Bland-Altman analysis showed large limits of agreement (-75.5-57.7 mL/min), with a bias of -8.9 and precision (standard deviation of bias) of 34 mL/min. Outliers were common, with 38% of C-G estimation values >120% of measured CrCl, and 18% of C-G estimates <80% of measured CrCl. Conclusions: Measured CrCl varied significantly from C-G estimates in hospitalized elderly patients. It is important to recognize characteristics of patients who may benefit from measurement of CrCl. Future studies should examine the impact of this variance on clinical outcomes.