Table 1.

Baseline characteristics of study participants

Baseline CharacteristicWith AKI (n = 82,711)No AKI (n = 782,222)
Demographics
    age (yr; mean ± SD)66.3 ± 12.461.3 ± 13.7
    female gender (%)3.25.0
    race (%)
        white71.672.0
        black21.720.5
        Hispanic4.04.0
        other1.92.0
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
    cancer14.610.5
    cardiac and vascular diseasesb37.528.9
    CKD4.52.0
    chronic obstructive pulmonary disease4.34.3
    diabetes33.622.9
    hypertension61.148.7
    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 (%)
    ACEIs/ARBs40.828.5
    β blockers29.523.7
    diuretics35.423.0
    NSAIDs25.626.9
    other nephrotoxic drugs13.810.9
    platelet aggregation inhibitors26.921.6
Hospitalization details
    hospitalization primary diagnosis (%)
        circulatory20.820.2
        digestive11.88.3
        infectious2.31.1
        neoplasms7.65.1
        respiratory10.26.5
        other47.258.9
    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.