Follow-up Care of Critically Ill Patients With Acute Kidney Injury: A Cohort Study.

Rationale & Objective: To evaluate follow-up care of critically ill patients with acute kidney injury (AKI).

Study Design: Retrospective cohort study.

Setting & Participants: Patients admitted to the intensive care unit (ICU) with AKI in Alberta, Canada from 2005 to 2018, who survived to discharge without kidney replacement therapy or estimated glomerular filtration rate <15 mL/min/1.73 m.

Exposure: AKI (defined as ≥50% or ≥0.3 mg/dL serum creatinine increase).

Outcomes: The primary outcome was the cumulative incidence of an outpatient serum creatinine and urine protein measurement at 3 months postdischarge. Secondary outcomes included an outpatient serum creatinine or urine protein measurement or a nephrologist visit at 3 months postdischarge.

Analytical Approach: Patients were followed from hospital discharge until the first of each outcome of interest, death, emigration from the province, kidney replacement therapy (maintenance dialysis or kidney transplantation), or end of study period (March 2019). We used non-parametric methods (Aalen-Johansen) to estimate the cumulative incidence functions of outcomes accounting for competing events (death and kidney replacement therapy).

Results: There were 29,732 critically ill adult patients with AKI. The median age was 68 years (IQR, 57-77), 39% were female, and the median baseline estimated glomerular filtration rate was 72 mL/min/1.73 m (IQR, 53-90). The cumulative incidence of having an outpatient creatinine and urine protein measurement at 3 months postdischarge was 25% (95% CI, 25-26). At 3 months postdischarge, 64% (95% CI, 64-65) had an outpatient creatinine measurement, 28% (95% CI, 27-28) had a urine protein measurement, and 5% (95% CI, 4-5) had a nephrologist visit.

Limitations: We lacked granular data, such as urine output.

Conclusions: Many critically ill patients with AKI do not receive the recommended follow-up care. Our findings highlight a gap in the transition of care for survivors of critical illness and AKI.