Renal complications and subsequent mortality in acute critically ill patients without pre-existing renal disease

Abstract

Background: Most studies of long-term renal outcomes after acute critical illness have enrolled patients with pre-existing renal dysfunction. We assessed renal outcomes in patients who did not have pre-existing renal disease and who were admitted to hospital for acute critical illness.

Methods: We identified adults who did not have pre-existing renal disease and who were admitted to hospital for acute critical illness between 2000 and 2011, from the Taiwan National Health Insurance Research Database. Each patient was matched 1:2 with controls without acute critical illness, according to age, sex and index date. A subset was further matched 1:1 with controls using propensity scores. Outcomes included acute kidney injury, chronic kidney disease and end-stage renal disease.

Results: We evaluated 33 613 patients with acute critical illness matched to 63 148 controls, of whom 14 218 were propensity matched to 14 218 controls. Patients with acute critical illness had incidence rates per 10 000 person-years of 9.45 for acute kidney injury, 78.3 for chronic kidney disease and 21.0 for end-stage renal disease. In the propensity-matched cohort, patients with acute critical illness had significantly higher risks of acute kidney injury (adjusted hazard ratio [aHR] 2.92, 95% confidence interval [CI] 1.78-4.77), chronic kidney disease (aHR 1.81, 95% CI 1.57-2.08), and end-stage renal disease (aHR 3.60, 95% CI 2.50-5.18). Acute critical illness conferred higher mortality risk among patients who subsequently developed end-stage renal disease (aHR 3.37, 95% CI 2.07-5.49) or chronic kidney disease (aHR 2.16, 95% CI 1.67-2.80).

Interpretation: Patients with acute critical illness and without pre-existing renal disease have a higher risk of adverse renal outcomes and subsequent mortality. A resolved episode of critical illness has implications for future renal function surveillance, even in patients without pre-existing renal disease.

Figure 1:

Flowchart of study design and patient selection. Note: ACI = acute critical illness, AKI = acute kidney injury, CRD = chronic renal disease, ESRD = end-stage renal disease.

Figure 2:

Cumulative incidence of acute kidney injury (A), chronic kidney disease (B) and end-stage renal disease (C) in individuals with and without critical illness by propensity-score matching.

Figure 3:

Cumulative incidence of death after development of acute kidney disease (A), chronic kidney disease (B) and end-stage renal disease (C) in the age- and sex-matched cohorts.