Discordance in renal function estimates between different equations: impact on treatment and safety in critically ill patients – A retrospective study

Pharmacy Practice

  • Worapong Sungsana1The College of Pharmacotherapy of Thailand, Nonthaburi, Thailand., 2Faculty of Pharmaceutical Sciences, Huachiew Chalermprakiet University, Samut Prakan, Thailand.
  • Chotirat Nakaranurack3B. Pharm, BCP, Department of Pharmacy Practice, Faculty of Pharmaceutical Sciences, Chulalongkorn University, Bangkok, Thailand.
  • Weerachai Chaijamorn3B. Pharm, BCP, Department of Pharmacy Practice, Faculty of Pharmaceutical Sciences, Chulalongkorn University, Bangkok, Thailand.
  • Nattachai Srisawat4M.D., PhD., Division of Nephrology, Department of Medicine, Faculty of Medicine, Chulalongkorn University, Bangkok, Thailand., 5Excellence Center for Critical Care Nephrology, King Chulalongkorn Memorial Hospital, Thai Red Cross Society, Bangkok, Thailand., 6Center of Excellence in Critical Care Nephrology and Critical Care Nephrology Research Unit, Chulalongkorn University, Bangkok, Thailand., 7Academy of Science, Royal Society of Thailand, Bangkok, Thailand., 8Tropical Medicine Cluster, Chulalongkorn University, Bangkok, Thailand.

Volume 24 Issue 1 Pages 1-9

DOI: 10.18549/PharmPract.2026.1.3424

Abstract

Background: Optimizing antibiotic dosages in critically ill patients is challenging. There are several equations to estimate the estimating renal clearance. The combined creatinine and cystatin C equation revealed significant discordance in dosing when compared with creatinine-based equations. Currently, there are no published studies on the impact of discordant antibiotic dosing rates on clinical outcomes in critically ill patients. Objective: This study evaluated the treatment and safety outcomes between groups with discordance and concordance regarding overall antibiotic dosing adjustments based on the Cockcroft-Gault (CG) and the CKD-EPI eGFRcr-cys 2021 in critically ill patients. We also compared adverse drug events (ADEs) between the discordance and concordance groups for each antibiotic agent. Methods: A retrospective observational study was conducted on adult patients in medical intensive care units who were administered antibiotics as part of the antimicrobial stewardship program. Cystatin C and creatinine levels were measured on the same day. Differences in treatment outcomes and ADEs between the concordance and discordance groups were assessed using Pearson’s chi-squared and Mann–Whitney U tests. Results: A total of 171 patients with serum cystatin C were included. The mean ± standard deviation (SD) age and BMI were 67.23 ± 17.45 years and 22.71 ± 4.58 kg/m2. Meropenem was the most frequent antibiotic agent use (75.44%). Thirty-five patients (20.47%) were categorized into the concordance group, while one hundred and thirty-six patients (79.53%) were placed in the discordance group. There were no statistically significant differences between the concordance group and discordance group for treatment outcomes. In the discordance group, there was a significantly higher incidence of acute kidney injury (AKI) compared to the concordance group, with rates of 56.76% versus 22.22% (p = 0.009). Additionally, the discordance group also experienced a significantly higher rate of AKI with colistin, at 77.78% compared to 41.67% in the concordance group (p = 0.012). The highest discordance drug was piperacillin/tazobactam (55.26%), followed by aminoglycosides (50.00%) and vancomycin (49.02%). Conclusions: Our study showed that using a cystatin C-based equation may help prevent AKI without negatively impacting clinical outcomes. Future clinical research is required with large populations.

Keywords

  • Adverse drug events
  • Antibiotic; Critically ill
  • Creatinine
  • Cystatin C
Pharmacy Practice

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