Highlights
- Higher hospital-level CKRT utilization is independently associated with a 15% lower adjusted probability of death in critically ill patients with AKI.
- The study identified a clear volume-outcome relationship, where hospitals in the highest quartile of CKRT use (≥ 31.5% of KRT patients) showed the most significant survival benefits.
- The findings suggest that institutional experience, specialized nursing proficiency, and standardized protocols inherent in high-volume centers are vital for optimizing outcomes in complex renal support.
Introduction: The Complexity of Renal Support in the ICU
The management of acute kidney injury (AKI) in the intensive care unit (ICU) remains one of the most resource-intensive and clinically challenging aspects of critical care. For patients requiring kidney replacement therapy (KRT), clinicians typically choose between intermittent hemodialysis (IHD) and continuous kidney replacement therapy (CKRT). While CKRT is often favored for hemodynamically unstable patients due to its superior fluid balance control and slower solute clearance, the optimal utilization strategy at a hospital-wide level has remained a subject of debate. Historically, in high-risk medical and surgical procedures, a higher volume of cases is frequently associated with improved clinical processes and patient survival. This study by Neyra et al. (2025) sought to determine if this ‘practice-makes-perfect’ paradigm applies to the delivery of CKRT in U.S. hospitals.
Study Design and Methodology
This multicenter cohort study utilized data from the Premier Incorporated AI (PINC-AI) database, encompassing a diverse array of U.S. acute care hospitals. The researchers focused on critically ill adults with AKI who received KRT in hospitals that offered both CKRT and IHD.
Population and Data Source
The analysis included 49,685 patients admitted to 426 hospitals. The inclusion criteria ensured that the study focused on institutions capable of providing both continuous and intermittent modalities, thereby reflecting real-world clinical decision-making where both options are available.
Defining CKRT Utilization
Hospitals were categorized into quartiles based on their annual CKRT utilization rate (the percentage of KRT patients treated with CKRT). This allowed the researchers to examine the association between institutional ‘volume’ or ‘experience’ with the modality and all-cause hospital mortality by day 90. The primary outcome was risk-adjusted hospital mortality, accounting for patient-level comorbidities, severity of illness, and hospital characteristics.
Key Findings: The Volume-Outcome Relationship
The study demonstrated a robust and statistically significant association between higher hospital-level CKRT utilization and lower patient-level mortality.
Quantitative Analysis of Mortality Risk
The results indicated that patients treated in hospitals with the highest CKRT utilization (Quartile 4, ≥ 31.5% of KRT patients) had a 15% lower adjusted probability of death compared to those in the lowest utilization quartile (Quartile 1, < 8%). When using hazard ratios to assess the risk over time, the third quartile (aHR 0.93; 95% CI: 0.89-0.98) and the fourth quartile (aHR 0.85; 95% CI: 0.81-0.89) both showed significantly lower mortality compared to the first quartile. These findings were consistent across several sensitivity analyses, reinforcing the validity of the observed association.
Threshold Effects
Interestingly, the data suggests a potential threshold effect. Hospitals where CKRT was utilized in more than approximately 30% of the AKI-KRT population saw a marked improvement in outcomes. This suggests that a certain level of institutional frequency is required to maintain the proficiency and infrastructure necessary for optimal CKRT delivery.
Clinical Implications and Expert Commentary
The findings of Neyra et al. have profound implications for how ICU kidney replacement programs are structured and managed. The observed benefit in high-utilization centers likely stems from a combination of technical, clinical, and organizational factors.
Mechanistic Insights into the Volume-Outcome Association
Why does higher utilization lead to better outcomes? In the context of CKRT, several factors are at play:
1. Nursing Proficiency and Technical Competence
CKRT is a technically demanding therapy that requires constant monitoring, circuit management, and troubleshooting. In high-volume centers, ICU nursing staff gain more frequent exposure to the equipment and protocols, leading to fewer technical errors, reduced circuit downtime, and more accurate fluid balance management.
2. Standardized Clinical Protocols
Hospitals that frequently use CKRT are more likely to have established, evidence-based protocols for anticoagulation, electrolyte replacement, and dose adjustment. Standardization reduces clinical variability and ensures that patients receive a more consistent and high-quality therapy.
3. Multidisciplinary Expertise
High-utilization centers often foster a closer collaboration between nephrologists and intensivists. This multidisciplinary approach ensures that the transition between modalities and the daily titration of therapy are optimized for the patient’s evolving physiological state.
Study Limitations and Considerations
While the study provides compelling evidence, it is important to acknowledge its observational nature. The PINC-AI database, while extensive, may not capture every granular clinical detail, such as the specific reason for choosing CKRT over IHD in individual cases. Furthermore, while risk-adjustment was thorough, unmeasured confounding variables related to hospital quality of care could still influence the results. It is also worth noting that ‘utilization rate’ is a proxy for institutional experience and does not directly measure the quality of the CKRT delivered.
Conclusion: Moving Toward Institutional Excellence in KRT
The association between higher hospital-level CKRT utilization and reduced mortality underscores the importance of institutional experience in managing critically ill patients with AKI. For healthcare administrators and clinical leaders, these findings suggest that consolidating KRT expertise and ensuring a minimum volume of CKRT procedures may be a viable strategy for improving patient outcomes. As the complexity of ICU care continues to rise, focusing on the quality and frequency of high-stakes interventions like CKRT will be essential for reducing the burden of AKI-related mortality.
References
1. Neyra JA, Echeverri J, Bronson-Lowe D, Plopper C, Harenski K, Murugan R. Association of hospital-level continuous kidney replacement therapy use and mortality in critically ill patients with acute kidney injury. Intensive Care Med. 2025 Jul;51(7):1271-1281. doi: 10.1007/s00134-025-07993-z.
2. Ronco C, Bellomo R, Homel P, et al. Effects of different doses in continuous veno-venous haemofiltration on outcomes of acute renal failure: a prospective randomised trial. Lancet. 2000;356(9223):26-30.
3. Gaudry S, Hajage D, Schortgen F, et al. Initiation Strategies for Renal-Replacement Therapy in the Intensive Care Unit. N Engl J Med. 2016;375(2):122-133.
