Impact of the intensity of intermittent renal replacement therapy in critically ill patients



Intermittent renal replacement therapy (IRRT) is prescribed across intensive care units (ICU) worldwide. While research regarding the prescribed dialysis dose has not yielded results concerning mortality, it is still unknown whether the same applies to the actual delivered dose.


We retrospectively analyzed two different cohorts of patients (562 IRRT sessions) who were admitted to the intensive care units at Hospital Clínic of Barcelona and required renal replacement therapy with IRRT. The first cohort included patients with acute kidney injury (AKI) (n = 42) and the second included patients already on chronic hemodialysis (CKD 5D) (n = 47). Only patients who had at least 3 recorded hemodialysis sessions in the ICU and with no previous continuous renal replacement therapy (CRRT) were included. The achieved dose was measured as Kt (L) by ionic dialysance and the primary endpoint was 90-day mortality.


Ninety-day mortality was 40.5% (n = 17) in the AKI cohort and 23.9% (n = 11) in the CKD 5D cohort with mean Kt of 43 ± 8.27 L and 47 ± 9.65 L respectively. Kt dose of IRRT was associated with 90-day mortality in the AKI cohort in a multivariate surveillance analysis adjusted for confounding factors (HR 0.935 [0.88–0.99], p = 0.02). Only the Kt dose and age remained statistically associated with the outcome in the AKI cohort.


Delivered dialysis dose as measured by ionic-dialysance Kt may be associated with survival in critically-ill patients with AKI, while it does not seem to affect outcomes in critically-ill CKD 5D patients. This exploratory analysis will need confirmation in larger prospective studies.

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Data availability

The datasets used and/or analysed during the current study are available from the corresponding author on reasonable request.


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Hospital Clínic Intensive Care Working Group (GTMC, Grup de treball del Malalt crític): Sara Fernández, Josep Maria Nicolàs, Pedro Castro, Intensive Care Unit, Internal Medicine Department, Hospital Clínic, IDIBAPS; Rut Andrea, Xavier Bosch, José Tomás Ortiz, Acute Cardiac Care, Cardiology Department, Hospital Clínic, IDIBAPS; Enric Reverter, Javier Fernández, Àngels Escorsell, Intensive Care Unit, Hepatology Department, Hospital Clínic, IDIBAPS; Jordi Mercadal, Carlos Ferrando, Xavier Borrat, Surgical ICU, Anesthesiology Department, Hospital Clínic, IDIBAPS; Antoni Torres, Joan Ramón Badia, Miquel Ferrer, Intensive Care Unit, Pneumology Department, Hospital Clínic, IDIBAPS; Eduard Quintana, Daniel Pereda, Elena Sandoval, Manel Castellà, Irene Rovira, Intensive care unit, Cardiovascular-Surgery Department, Hospital Clínic, IDIBAPS.


The authors received no financial support for the research, authorship, and publication of this article.

Author information





AMA, PS and EP contributed to the study conception and design. Material preparation, data collection and analysis were performed byAMA, PA and ER. The first draft of the manuscript was written by Alícia Molina. MB, DC, GP, RA, SF, ER, JM and EQ: have interpreted the data, revised the manuscript, provided intellectual content and approved the final version.

Corresponding author

Correspondence to Esteban Poch.

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No potential conflict of interest was reported by the authors. The results presented in this paper have not been published previously in whole or part, except in abstract format.

Ethical approval

The Study was approved by the Ethics Committee of the Hospital Clinic and conformed to the ethical guidelines of the Helsinki Declaration (as revised in Tokyo 2004).

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Molina-Andújar, A., Alcubilla, P., Santiago, P. et al. Impact of the intensity of intermittent renal replacement therapy in critically ill patients. J Nephrol 34, 105–112 (2021).

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  • Intermittent renal replacement therapy
  • Dialysis dose
  • Acute kidney injury
  • Intensive care unit
  • Ionic dialysance
  • Kt