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Table 3 Stepwise model of unplanned 90 day readmission or death after hospital discharge

From: Acute kidney injury as an independent risk factor for unplanned 90-day hospital readmissions

  Full model Best stepwise model
  OR 95% CI p-value OR 95% CI p-value Variable Inclusion %b
Characteristics
 Age (per 10 years) 1.19 (1.14–1.24) <0.001 1.17 (1.13–1.21) <0.001 100
 Age term squared 1.00 (0.99–1.02) 0.388     12.4
 Male sex 1.08 (1.00–1.18) 0.061     26.4
 Residential care 1.63 (1.36–1.94) <0.001 1.37 (1.42–1.98) <0.001 100
 Deprived (highest vs all other quintiles) 1.11 (0.96–1.29) 0.150     15.4
 Rural (settlement <3000) 0.88 (0.80–0.97) 0.008 0.86 (0.78–0.94) 0.001 65.2
Admission context
 Admissions in prior 1 year (per admission) 1.21 (1.17–1.25) <0.001 1.23 (1.18–1.27) <0.001 100
 Length of stay (per week) 0.99 (0.98–1.00) 0.242     7.0
 Emergency admission 1.81 (1.64–2.01) <0.001 1.89 (1.72–2.08) <0.001 100
 Medical ward admission 1.09 (0.99–1.19) 0.066     24.6
 Intensive care admission 0.88 (0.68–1.13) 0.308     5.2
Renal function
 No AKI (reference group)   
 AKI stage 1 1.57 (1.36–1.80) <0.001 1.50 (1.33–1.70) <0.001 100
 AKI stage 2 2.35 (1.92–2.88) <0.001 2.23 (1.85–2.68) <0.001 100
 AKI stage 3 2.95 (2.29–3.80) <0.001 2.80 (2.22–3.53) <0.001 100
 Prior AKI count (per episode) 1.11 (1.02–1.22) 0.020     47.4
 Baseline eGFR linear terma 0.89 (0.82–0.96) 0.005 0.87 (0.80–0.94) <0.001  
 Baseline eGFR squared terma 1.01 (1.00–1.02) 0.001 1.01 (1.01–1.02) <0.001 91.0
 Discharge creatinine 20% > baseline 0.93 (0.80–1.08) 0.317     6.0
Comorbidity
 Cancer 1.59 (1.38–1.82) <0.001 1.59 (1.37–1.82) <0.001 100
 Cardiac failure 1.32 (1.12–1.55) 0.001 1.42 (1.21–1.66) <0.001 88.8
 Cerebrovascular disease 1.07 (0.89–1.27) 0.471     6.0
 Dementia 1.21 (0.92–1.60) 0.174     13.2
 Diabetes 1.33 (1.15–1.54) <0.001 1.38 (1.19–1.60) <0.001 92.0
 Hemiplegia 0.91 (0.56–1.47) 0.691     0.4
 Liver disease 1.19 (0.86–1.66) 0.299     11.2
 Myocardial infarction 1.13 (0.95–1.33) 0.170     13.6
 Peptic ulcer disease 0.90 (0.69–1.18) 0.464     2.0
 Peripheral vascular disease 1.00 (0.82–1.22) 0.994     0.6
 Pulmonary 1.44 (1.24–1.67) <0.001 1.47 (1.27–1.70) <0.001 99.2
 Rheumatic disease 0.92 (0.70–1.20) 0.525     2.4
  1. Abbreviations: AKI acute kidney injury, CI confidence interval, eGFR estimated glomerular filtration rate, OR odds ratio
  2. aModelled per 10 ml/min/1.73 m2 increase with a combination of linear and quadratic terms. Variable inclusion % applies to the baseline eGFR variable overall
  3. bIn 500 bootstrapped datasets