Impaired kidney function at hospital discharge and long-term renal and overall survival in patients who received CRRT.

BACKGROUND AND OBJECTIVES: Critically ill patients with AKI necessitating renal replacement therapy (RRT) have high in-hospital mortality, and survivors are at risk for kidney dysfunction at hospital discharge. The objective was to evaluate the association between impaired kidney function at hospital discharge with long-term renal and overall survival.

DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS: Degree of kidney dysfunction in relation to long-term effects on renal survival and patient mortality was investigated in a retrospective cohort study of 1220 adults admitted to an intensive care unit who received continuous RRT between 1994 and 2010.

RESULTS: After hospital discharge, median follow-up of survivors (n=475) was 8.5 years (range, 1-17 years); overall mortality rate was 75%. Only 170 (35%) patients were discharged with an estimated GFR (eGFR) >60 ml/min per 1.73 m(2). Multivariate proportional hazards regression analysis demonstrated that age, nonsurgical type of admission, preexisting kidney disease, malignancy, and eGFR of 29-15 ml/min per 1.73 m(2) (hazard ratio [HR], 1.62; 95% confidence interval [CI], 1.01 to 2.58) and eGFR <15 ml/min per 1.73 m(2) (HR, 1.93; 95% CI, 1.23 to 3.02) at discharge were independent predictors of increased mortality. Renal survival was significantly associated with degree of kidney dysfunction at discharge. An eGFR of 29-15 ml/min per 1.73 m(2) (HR, 26.26; 95% CI, 5.59 to 123.40) and <15 ml/min per 1.73 m(2) (HR, 172.28; 95% CI, 37.72 to 786.75) were independent risk factors for initiation of long-term RRT.

CONCLUSIONS: Most critically ill patients surviving AKI necessitating RRT have impaired kidney function at hospital discharge. An eGFR <30 ml/min per 1.73 m(2) is a strong risk factor for decreased long-term survival and poor renal survival.