Table 1.

Baseline characteristics of study participants

Baseline CharacteristicWith AKI (n = 82,711)No AKI (n = 782,222)
    age (yr; mean ± SD)66.3 ± 12.461.3 ± 13.7
    female gender (%)3.25.0
    race (%)
Follow-up time (yr; mean ± SD)2.08 ± 1.422.36 ± 1.43
eGFR (ml/min per 1.73 m2; median [first and third quartiles])
    baseline93.8 (71.0, 122.2)86.3 (70.3, 103.8)
    after discharge75.0 (56.3, 96.7)81.5 (65.8, 97.9)
Concurrent conditions before admission (%)
    previous AKIa1.10.3
    cardiac and vascular diseasesb37.528.9
    chronic obstructive pulmonary disease4.34.3
    neurodegenerative diseasesc5.03.9
    mental health disordersd25.231.3
    hospitalization in previous month0.90.4
    hospitalization in previous yeare8.06.1
Medication use before admission (%)
    β blockers29.523.7
    other nephrotoxic drugs13.810.9
    platelet aggregation inhibitors26.921.6
Hospitalization details
    hospitalization primary diagnosis (%)
    mechanical ventilationf6.450.4
    length of stay (d; median [first and third quartiles])10 (5, 27)4 (2, 8)
Hospitalization between 30 and 90 d after discharge (%)13.710.0
  • ACEI, angiotensin-converting enzyme inhibitor; ARB, angiotensin receptor blocker; NSAID, nonsteroidal anti-inflammatory drug.

  • aDefined as the presence of at least one ICD-9-CM diagnostic code 584.xx in the 2 yr before the index admission date.

  • bInclude congestive heart failure, ischemic disease, arrhythmia, peripheral vascular disease, stroke, and valvular disease.

  • cInclude Parkinson disease, Alzheimer disease, other dementia, and multiple sclerosis.

  • dInclude major depression, posttraumatic stress disorder, anxiety disorder, schizophrenia, bipolar disorder, alcohol abuse, and drug abuse.

  • eExcludes hospitalizations in the previous month.

  • fDefined by the presence of ICD-9-CM procedure code 96.04 or 96.7x during hospitalization.