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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