Long-term kidney function of patients discharged from hospital after an intensive care admission: observational cohort study.

The long-term trajectory of kidney function recovery or decline for survivors of critical illness is incompletely understood. Characterising changes in kidney function after critical illness and associated episodes of acute kidney injury (AKI), could inform strategies to monitor and treat new or progressive chronic kidney disease. We assessed changes in estimated glomerular filtration rate (eGFR) and impact of AKI for 1301 critical care survivors with 5291 eGFR measurements (median 3 [IQR 2, 5] per patient) between hospital discharge (2004-2008) and end of 7 years of follow-up. Linear mixed effects models showed initial decline in eGFR over the first 6 months was greatest in patients without AKI (- 9.5%, 95% CI - 11.5% to - 7.4%) and with mild AKI (- 12.3%, CI - 15.1% to - 9.4%) and least in patients with moderate-severe AKI (- 4.3%, CI - 7.0% to - 1.4%). However, compared to patients without AKI, hospital discharge eGFR was lowest for the moderate-severe AKI group (median 61 [37, 96] vs 101 [78, 120] ml/min/1.73m) and two thirds (66.5%, CI 59.8-72.6% vs 9.2%, CI 6.8-12.4%) had an eGFR of < 60 ml/min/1.73m through to 7 years after discharge. Kidney function trajectory after critical care discharge follows a distinctive pattern of initial drop then sustained decline. Regardless of AKI severity, this evidence suggests follow-up should incorporate monitoring of eGFR in the early months after hospital discharge.