Differentiating True Nephrotoxicity From Pseudo-nephrotoxicity: A Prospective Comparative Study of Vancomycin Plus Piperacillin-Tazobactam vs. Meropenem Using Serum Creatinine and Cystatin-C

Trial statusNot yet recruiting
Trial phaseNot listed
Trial typeObservational
Biological sexAll
Age18+
SponsorKing Faisal Specialist Hospital & Research Center

About this trial

This prospective comparative observational study will compare the incidence of true nephrotoxicity in adult patients receiving vancomycin in combination with either piperacillin-tazobactam or meropenem.

Vancomycin plus piperacillin-tazobactam has been associated with a higher incidence of kidney injury based mainly on increases in serum creatinine. However, it remains uncertain whether these increases represent true kidney injury or pseudo-nephrotoxicity, in which serum creatinine increases without a corresponding decline in kidney function.

To address this uncertainty, the study will prospectively assess kidney function using both serum creatinine and cystatin C. True nephrotoxicity will be identified when changes in both biomarkers meet the study criteria for acute kidney injury, while an increase in serum creatinine without a corresponding cystatin C increase will be considered pseudo-nephrotoxicity.

The study will compare true nephrotoxicity between patients receiving vancomycin plus piperacillin-tazobactam and those receiving vancomycin plus meropenem. It will also evaluate the timing, persistence, severity, and recovery of kidney injury. The results may help clarify whether the higher rates of nephrotoxicity reported with vancomycin plus piperacillin-tazobactam represent true renal injury and may help guide antibiotic selection when balancing antimicrobial coverage and kidney safety.

Eligibility criteria

This trial does not accept healthy volunteers

Qualifiers

Age ≥18 years.

Receipt of vancomycin in combination with either piperacillin-tazobactam or meropenem, with both antimicrobial agents prescribed by the treating physician and expected to be administered concomitantly for >48 hours.

Disqualifiers

Known advanced chronic kidney disease (CKD), defined as a baseline estimated glomerular filtration rate (eGFR) <30 mL/min/1.73 m², or dialysis dependence..

Pregnancy.

Receipt of renal replacement therapy prior to enrollment.

Obstructive uropathy causing AKI.

Trial population

Patients admitted to King Faisal Specialist Hospital and Research Center, and received vancomycin combined with either piperacillin-tazobactam or meropenem from August 2026 until achieving the pre-specified sample size will be screened for the inclusion and exclusion criteria

Trial design

Design model

Other

Time perspective

Prospective

Treatments tested in this trial

Not listed

Trial groups

304 Participants
are grouped into 2 trial groups
Group A: Vancomycin - Piperacillin Tazobactam
Group B: Vancomycin - Meropenem

Trial outcomes

Primary outcomes

1

To assess the incidence of developing true nephrotoxicity in patients receiving vancomycin + piperacillin-tazobactam versus vancomycin + meropenem.

True nephrotoxicity is defined as both serum creatinine and cystatin-C meet the AKI criteria on 2026 KDIGO criteria. Serum creatinine-based AKI: defined as any of the following: Change in SCr≥0.3 mg/dL within 48 hours OR SCr≥1.5×baseline within 7 days. Cystatin-C-Based AKI is defined as any of the following: ≥50% increase from baseline cystatin-C OR absolute increase ≥0.3 mg/L from baseline

Time frame
From enrollment until 72 hours from stopping vancomycin therapy

Secondary outcomes

1

Difference in time to AKI onset based on serum creatinine and cystatin C between the two groups

Time to AKI onset will be determined independently according to serum creatinine-based and cystatin C-based AKI criteria. Time to AKI onset will be calculated from initiation of the study antibiotic regimen to the first time the participant meets the respective AKI criterion. The difference in time to AKI onset between serum creatinine-based and cystatin C-based assessments will be evaluated and compared between patients receiving vancomycin plus piperacillin-tazobactam and those receiving vancomycin plus meropenem.

Time frame
From enrollment until 72 hours from stopping vancomycin
2

Incidence of Transient and Persistent Acute Kidney Injury According to the 2026 KDIGO Criteria between the two study groups

AKI will be classified as transient or persistent according to the 2026 KDIGO AKI/AKD criteria based on the duration of increased serum creatinine or cystatin C, or reduced urine output. The incidence of transient and persistent AKI will be compared between patients receiving vancomycin plus piperacillin-tazobactam and those receiving vancomycin plus meropenem.

Time frame
From enrollment until 72 hours from vancomycin therapy cessation
3

Recovery from AKI according to the 2026 KDIGO Criteria

Recovery from AKI will be assessed according to the 2026 KDIGO AKI/AKD criteria using serum creatinine-based and cystatin C-based assessments. The proportion of participants achieving recovery from AKI will be determined and compared between patients receiving vancomycin plus piperacillin-tazobactam and those receiving vancomycin plus meropenem.

Time frame
From AKI onset through 90 days after AKI onset.
4

Severity of AKI staged according to the 2026 KDIGO criteria between the two groups

The severity of acute kidney injury (AKI) will be assessed according to the 2026 Kidney Disease: Improving Global Outcomes (KDIGO) AKI/AKD criteria. Participants who develop AKI will be classified according to AKI severity (Stage 1, Stage 2, or Stage 3) based on serum creatinine and urine output criteria. The distribution of AKI severity stages will be compared between patients receiving vancomycin plus piperacillin-tazobactam and those receiving vancomycin plus meropenem.

Time frame
From AKI onset through 7 days after AKI onset.

Other outcomes

Sponsors and contacts

Click on the lead sponsor to view all of their trials.

This trial is not recruiting at the moment. You can still explore other options: