Long-term quality of life in critically ill patients with acute kidney injury treated with renal replacement therapy: a matched cohort study

Abstract

Introduction: Acute kidney injury (AKI) is a common complication in intensive care unit (ICU) patients and is associated with increased morbidity and mortality. We compared long-term outcome and quality of life (QOL) in ICU patients with AKI treated with renal replacement therapy (RRT) with matched non-AKI-RRT patients.

Methods: Over 1 year, consecutive adult ICU patients were included in a prospective cohort study. AKI-RRT patients alive at 1 year and 4 years were matched with non-AKI-RRT survivors from the same cohort in a 1:2 (1 year) and 1:1 (4 years) ratio based on gender, age, Acute Physiology and Chronic Health Evaluation II score, and admission category. QOL was assessed by the EuroQoL-5D and the Short Form-36 survey before ICU admission and at 3 months, 1 and 4 years after ICU discharge.

Results: Of 1953 patients, 121 (6.2%) had AKI-RRT. AKI-RRT hospital survivors (44.6%; N = 54) had a 1-year and 4-year survival rate of 87.0% (N = 47) and 64.8% (N = 35), respectively. Forty-seven 1-year AKI-RRT patients were matched with 94 1-year non-AKI-RRT patients. Of 35 4-year survivors, three refused further cooperation, three were lost to follow-up, and one had no control. Finally, 28 4-year AKI-RRT patients were matched with 28 non-AKI-RRT patients. During ICU stay, 1-year and 4-year AKI-RRT patients had more organ dysfunction compared to their respective matches (Sequential Organ Failure Assessment scores 7 versus 5, P < 0.001, and 7 versus 4, P < 0.001). Long-term QOL was, however, comparable between both groups but lower than in the general population. QOL decreased at 3 months, improved after 1 and 4 years but remained under baseline level. One and 4 years after ICU discharge, 19.1% and 28.6% of AKI-RRT survivors remained RRT-dependent, respectively, and 81.8% and 71% of them were willing to undergo ICU admission again if needed.

Conclusion: In long-term critically ill AKI-RRT survivors, QOL was comparable to matched long-term critically ill non-AKI-RRT survivors, but lower than in the general population. The majority of AKI-RRT patients wanted to be readmitted to the ICU when needed, despite a higher severity of illness compared to matched non-AKI-RRT patients, and despite the fact that one quarter had persistent dialysis dependency.

Fig. 1

Patient cohort. N number, AKI acute kidney injury, RRT renal replacement therapy, ICU intensive care unit

Fig. 2

EQ-5D assessments in the 1-year cohort. Percentages of patients with some or severe problems per dimension at the three different time points. The X-axis represents the different dimensions of the EQ-5D. The Y-axis represents the percentages (%) of patients with some or severe problems in a respective dimension. Only significant P values (Chi-Square test) are shown above the respective dimensions. AKI acute kidney injury, QOL quality of life, RRT renal replacement therapy

Fig. 3

SF-36 assessments in the 1-year cohort. Norm-based median scores per domain at the three different time points. The X-axis represents the different domains of the SF-36. The Y-axis represents the norm-based median scores in a respective domain of the SF-36. A norm-based median score between 47 and 53 in a group of patients is considered as normal or average. Norm-based median scores below 47 indicate impaired functioning or below average; norm-based median scores above 53 indicate better functioning or above average. Only significant P values (Mann–Whitney U analysis) are shown above the respective domains. AKI acute kidney injury, BP bodily pain, GH general health, MCS mental component score, MH mental health, PCS physical component score, PF physical functioning, QOL quality of life, RE role emotional, RP role physical, RRT renal replacement therapy, SF social functioning, VT vitality

Fig. 4

EQ-5D assessments in the 4-year cohort. Percentages of patients with some or severe problems per dimension at the four different time points. The X-axis represents the different dimensions of the EQ-5D. The Y-axis represents the percentages (%) of patients with some or severe problems in a respective dimension. Only significant P values (Chi Square test) are shown above the respective dimensions. AKI acute kidney injury, QOL quality of life, RRT renal replacement therapy

Fig. 5

SF-36 assessments in the 4-year cohort. Norm-based median scores per domain at the four different time points. The X-axis represents the different domains of the SF-36. The Y-axis represents the norm-based median scores in a respective domain of the SF-36. A norm-based median score between 47 and 53 in a group of patients is considered as normal or average. Norm-based median scores below 47 indicate impaired functioning or below average; norm-based median scores above 53 indicate better functioning or above average. Only significant P values (Mann–Whitney U analysis) are shown above the respective domains. AKI acute kidney injury, BP bodily pain, GH general health, MCS mental component score, MH mental health, PCS physical component score, PF physical functioning, QOL quality of life, RE role emotional, RP role physical, RRT renal replacement therapy, SF social functioning, VT vitality