CKD Stage Predicts Mortality and Dialysis Dependence in Critically Ill Patients

Patients with more advanced chronic kidney disease (CKD) face substantially worse outcomes after admission to the intensive care unit (ICU), including higher short-term mortality, greater likelihood of requiring kidney replacement therapy (KRT), and longer hospital stays, according to findings published in JAMA Network Open.¹

The population-based cohort study analyzed 531,090 consecutive ICU admissions across Ontario, Canada, and found that CKD was present in approximately 25% of all critically ill adults, which is double the disease's prevalence in the general Canadian population. Worsening baseline kidney function was independently associated with increased mortality and KRT initiation even after adjustment for illness severity, comorbidities, and critical care interventions.¹

Study Design

The cohort included adults admitted to an ICU between November 1, 2008, and February 28, 2021, who had a baseline outpatient serum creatinine measurement obtained 7 to 365 days prior to admission. Estimated glomerular filtration rate (eGFR) was calculated using the 2021 CKD Epidemiology Collaboration formula and used to classify patients by KDIGO CKD stage: no CKD (eGFR ≥60, mL/min/1.73 m²; 75%); stage 3a (eGFR 45-59; 12%); stage 3b (eGFR 30-44; 7%); stage 4 (eGFR 15-29; 3%); nondialysis-dependent stage 5 (eGFR <15; 1%); and maintenance dialysis (2%).^1,2

Primary outcomes included all-cause mortality at ICU discharge, hospital discharge, and 90 days. Secondary outcomes included KRT initiation during the ICU stay, KRT dependence at 90 days, and length of stay. Multivariable models adjusted for age, sex, comorbidities, illness severity via the Multiple Organ Dysfunction Score (kidney component excluded), vasopressor and mechanical ventilation use, and presence of sepsis or septic shock.¹

Mortality

Mortality risk increased progressively with CKD severity through nondialysis-dependent stage 5. Relative to patients without CKD, adjusted odds ratios for 90-day mortality were about 1.14 (95% CI, 1.11–1.17) for stage 3a, 1.38 (95% CI, 1.34–1.42) for stage 3b, 1.95 (95% CI, 1.87–2.03) for stage 4, and 2.32 (95% CI, 2.14–2.52) for nondialysis-dependent stage 5.¹

Patients receiving maintenance dialysis did not follow this pattern, with a 90-day mortality odds ratio of about 1.92 (95% CI, 1.82–2.04), lower than nondialysis-dependent stage 5 and comparable to stage 4. The investigators suggested this may reflect better volume and metabolic control with dialysis, a lower threshold for ICU transfer in this population, or survival bias.^1,3

Kidney Replacement Therapy

Among patients who were not already receiving maintenance dialysis, the likelihood of initiating KRT during the ICU stay rose sharply by CKD stage. Adjusted odds for ICU KRT initiation relative to patients without CKD were 1.79 (95% CI, 1.68-1.90) for stage 3a, 3.02 (95% CI, 29.07-35.22) for stage 3b, 6.71 (95% CI, 6.23-7.22) for stage 4, and 32.00 (95% CI, 29.07-35.22) for nondialysis-dependent stage 5.¹

Among patients who survived to 90 days and had initiated KRT during their ICU stay, the proportion remaining KRT dependent increased markedly by stage: approximately 7.2% for those without CKD, 14.2% for stage 3a, 22.5% for stage 3b, 50.3% for stage 4, and 83.8% for previously nondialysis-dependent stage 5 CKD. KRT dependence at 90 days represents a well-accepted threshold for end-stage kidney disease (ESKD).^1,4

Length of Stay and Conclusions

Hospital length of stay increased progressively with CKD severity, with patients with nondialysis-dependent stage 5 CKD experiencing the longest stays. Patients on maintenance dialysis had shorter stays than those with nondialysis-dependent stage 5 CKD, mirroring the mortality pattern.¹

The authors concluded that the presence and severity of CKD were associated with adverse outcomes after ICU admission—including death, ESKD, and prolonged length of stay—and that these findings should inform risk prognostication, goals-of-care discussions, resource allocation, and health policy for this large and undercharacterized portion of the critical care population.^1,5

For pharmacists practicing in or supporting critical care settings, these findings reinforce the importance of baseline kidney function as a key driver of clinical risk in ICU patients. Patients with advanced CKD admitted to the ICU are at a substantially elevated risk for acute-on-chronic kidney injury, which can rapidly alter the pharmacokinetics of renally-cleared medications (eg, antibiotics, anticoagulants, electrolyte-altering agents), necessitating close monitoring and frequent dose reassessment. Pharmacists should also anticipate the high likelihood of KRT initiation in patients with stage 4 or nondialysis-dependent stage 5 CKD, as the initiation of dialysis introduces additional pharmacokinetic considerations related to drug clearance via the dialysis membrane.

REFERENCES

1. El Wadia H, Beauregard N, Silver SA, et al. Severity of chronic kidney disease and outcomes after admission to the intensive care unit. JAMA Netw Open. 2026;9(6):e2620192. doi:10.1001/jamanetworkopen.2026.20192

2. Inker LA, Eneanya ND, Coresh J, et al; Chronic Kidney Disease Epidemiology Collaboration. New creatinine- and cystatin C–based equations to estimate GFR without race. N Engl J Med. 2021;385(19):1737-1749. doi:10.1056/NEJMoa2102953

3. Arulkumaran N, Annear NM, Singer M. Patients with end-stage renal disease admitted to the intensive care unit: systematic review. Br J Anaesth. 2013;110(1):13-20. doi:10.1093/bja/aes401

4. Ostermann M, Lumlertgul N, James MT. Dialysis-dependent acute kidney injury—a risk factor for adverse outcomes. JAMA Netw Open. 2024;7(3):e240346. doi:10.1001/jamanetworkopen.2024.0346

5. Kidney Disease: Improving Global Outcomes (KDIGO) CKD Work Group. KDIGO 2024 clinical practice guideline for the evaluation and management of chronic kidney disease. Kidney Int. 2024;105(4S):S117-S314. doi:10.1016/j.kint.2023.10.018