Background
Methods
Data sources and study population
Study sample
Outcomes: readmissions and deaths
Exposures: patient, index admission and hospital characteristics
Statistical analysis
Results
Sample description
Variables | Total sample | 30-day unplanned readmission (%)a
| 30-day mortality (%)a
| |
---|---|---|---|---|
n | %a
| |||
Sociodemographic | ||||
Age (years, at index admission) | ||||
45– < 75 | 1303 | 26 | 20 | 1.8 |
75– < 85 | 2142 | 42 | 22 | 3.5 |
≥ 85 | 1629 | 32 | 20 | 5.5 |
Mean (SD)
| 80 (9.4) | 80 (8.8) | 84 (8.4) | |
Sex | ||||
Male | 2927 | 58 | 22 | 4.0 |
Female | 2147 | 42 | 19 | 3.2 |
Language other than English | ||||
Yes | 559 | 11 | 21 | 3.4 |
No | 4515 | 89 | 21 | 3.7 |
Marital status | ||||
Married | 2864 | 56 | 20 | 3.6 |
Not married | 2210 | 44 | 21 | 3.8 |
Region of residence | ||||
Major cities | 2535 | 50 | 20 | 4.1 |
Regional | 1566 | 31 | 21 | 3.5 |
Remote | 973 | 19 | 22 | 2.9 |
Education | ||||
No school certificate | 1134 | 23 | 21 | 3.8 |
School/Trade certificate, diploma | 3211 | 66 | 22 | 3.5 |
Tertiary degree | 524 | 11 | 18 | 5.0 |
Unknown | 205 | |||
Household income (AUD) | ||||
< 20,000 | 1994 | 57 | 31 | 5.5 |
20,000–39,000 | 914 | 26 | 28 | 5.7 |
40,000–69,999 | 363 | 10 | 28 | 4.8 |
≥ 70,000 | 220 | 6.3 | 26 | 4.0 |
Unknown | 1583 | |||
Private health insurance | ||||
Yes | 2131 | 42 | 19 | 3.8 |
No | 2943 | 58 | 22 | 3.6 |
Baseline health (self-reported) | ||||
Previous heart disease | ||||
Yes | 2408 | 47 | 21 | 3.5 |
No | 2666 | 53 | 20 | 3.8 |
Previous diabetes | ||||
Yes | 1213 | 24 | 21 | 3.1 |
No | 3861 | 76 | 21 | 3.9 |
Excellent memory | ||||
Yes | 505 | 10 | 21 | 3.0 |
No | 4569 | 90 | 21 | 3.7 |
Physical functioning score | ||||
0– < 75 (severe) | 2662 | 70 | 28 | 5.8 |
≥ 75 | 1127 | 30 | 25 | 2.7 |
Unknown | 1285 | |||
Duke Social Support Index | ||||
Mean (SD)
| 8.7(1.6) | 8.6 (1.6) | 8.6 (1.7) | |
Psychological distress | ||||
Very low | 3478 | 74 | 22 | 4.5 |
Low | 770 | 16 | 24 | 2.2 |
Medium | 312 | 6.6 | 27 | 4.5 |
High | 140 | 3 | 25 | 3.1 |
Unknown | 374 | |||
BMI | ||||
Underweight | 128 | 2.8 | 27 | 7.9 |
Normal | 1577 | 35 | 24 | 4.8 |
Overweight | 1616 | 36 | 24 | 3.8 |
Obese | 1191 | 26 | 20 | 2.3 |
Unknown | 562 | |||
Smoking status | ||||
Current smoker | 273 | 5.4 | 26 | 5.2 |
Ex-smoker | 2384 | 47 | 21 | 3.4 |
Never smoker | 2388 | 47 | 20 | 3.8 |
Unknown | 29 | |||
Alcohol (drinks per week) | ||||
None | 2230 | 46 | 22 | 3.8 |
1–14 drinks | 2083 | 43 | 22 | 4.3 |
≥ 15 drinks | 522 | 11 | 20 | 2.8 |
Unknown | 239 | |||
Hospitalisation history (Admitted Patient Data Collection, 6 year prior to baseline) | ||||
Previous CVD | ||||
Yes | 4669 | 92 | 21 | 3.6 |
No | 405 | 8 | 15 | 4.4 |
Previous heart failure | ||||
Yes | 1176 | 23 | 24 | 4.2 |
No | 3898 | 77 | 20 | 3.5 |
Previous renal disease | ||||
Yes | 564 | 11 | 26 | 3.9 |
No | 4510 | 89 | 20 | 3.6 |
Previous anaemia | ||||
Yes | 900 | 18 | 26 | 4.6 |
No | 4174 | 82 | 20 | 3.5 |
Previous atrial fibrillation | ||||
Yes | 1422 | 28 | 22 | 3.2 |
No | 3652 | 72 | 20 | 3.8 |
Previous dementia | ||||
Yes | 73 | 1.4 | 18 | 6.9 |
No | 5001 | 99 | 21 | 3.6 |
Hospitalisation history (Admitted Patient Data Collection, 12 months prior to index admission) | ||||
No. of admissions (last 12 months) | ||||
Mean (SD)
| 1.3 (2.9) | 1.9 (5.0) | 1.8 (3.4) | |
No. of hospital days (last 12 months) | ||||
Mean (SD)
| 7.0 (15) | 9.2 (18) | 11 (18) | |
Index admission characteristics | ||||
Primary diagnosis | ||||
Yes | 1973 | 39 | 20 | 2.3 |
No | 3101 | 61 | 21 | 4.6 |
Unplanned admission | ||||
Yes | 4180 | 82 | 22 | 3.8 |
No | 894 | 18 | 16 | 3.2 |
Length of stay (days) | ||||
1 | 450 | 8.9 | 18 | 2.7 |
2–6 | 1922 | 38 | 20 | 2.5 |
≥ 7 | 2702 | 53 | 21 | 4.7 |
Current comorbidity (Charlson Index) | ||||
Minor | 2933 | 58 | 19 | 2.7 |
Moderate | 1403 | 28 | 22 | 4.0 |
Severe | 738 | 15 | 25 | 6.8 |
Length of stay (days) | ||||
Median (IQR) | 7 (10) | 7 (12) | 12 (18) | |
Hospital characteristics | ||||
Hospital peer group | ||||
Principal referral | 2493 | 49 | 22 | 3.4 |
Major city | 537 | 11 | 20 | 5.0 |
District | 606 | 12 | 21 | 4.1 |
Community | 355 | 7 | 26 | 3.4 |
Private | 900 | 18 | 17 | 3.7 |
Others | 183 | 3.6 | 17 | 2.7 |
Heart failure service | ||||
Yes | 1695 | 33 | 22 | 3.6 |
No | 3379 | 67 | 20 | 3.7 |
Totals | 5074 | 100 | 21 | 3.7 |
Risk of 30-day readmission and death
Between-hospital variation in risk of readmission and/or death
Model | 1 | 2 | 3 | 4 | 5 |
---|---|---|---|---|---|
Random effects | |||||
Hospital variance | 0.14 | 0.15 | 0.13 | 0.11 | 0.09 |
ICC | 0.0205 | 0.0212 | 0.0172 | 0.0125 | 0.0074 |
P-value | 0.12 | 0.12 | 0.17 | 0.24 | 0.34 |
MOR | 1.43 | 1.44 | 1.41 | 1.37 | 1.32 |
PCV (%) | −1.82 | 9.95 | 14.94 | 22.9 | |
Fixed effects | Odds ratios | ||||
Sociodemographic | |||||
Age (years, at index admission) | |||||
45– < 75 | 1.00 | 1.00 | 1.00 | 1.00 | |
75– < 85 | 1.10 (0.93,1.31) | 1.10 (0.93,1.31) | 1.06 (0.89,1.27) | 1.06 (0.89,1.27) | |
≥ 85 | 1.01 (0.84,1.21) | 0.99 (0.82,1.19) | 0.92 (0.75,1.13) | 0.92 (0.75,1.13) | |
Sex | |||||
Male | 1.19 (1.04,1.37) | 1.23 (1.07,1.43) | 1.17 (1.00,1.37) | 1.18 (1.00,1.37) | |
Female | 1.00 | 1.00 | 1.00 | 1.00 | |
Marital status | |||||
Married | 0.90 (0.77,1.04) | 0.90 (0.78,1.05) | 0.91 (0.78,1.05) | ||
Not married | 1.00 | 1.00 | 1.00 | ||
Region of residence | |||||
Major cities | 1.00 | 1.00 | 1.00 | ||
Regional | 1.01 (0.86,1.19) | 1.03 (0.87,1.22) | 1.03 (0.87,1.22) | ||
Remote | 1.08 (0.90,1.31) | 1.13 (0.93,1.36) | 1.04 (0.83,1.29) | ||
Education | |||||
No school certificate | 1.00 | 1.00 | 1.00 | ||
School/trade/certificate/diploma | 1.11 (0.94,1.32) | 1.13 (0.95,1.35) | 1.14 (0.96,1.36) | ||
Tertiary degree | 0.89 (0.67,1.17) | 0.89 (0.67,1.18) | 0.91 (0.69,1.21) | ||
Private health insurance | |||||
Yes | 0.89 (0.77,1.03) | 0.92 (0.80,1.07) | 0.97 (0.83,1.14) | ||
No | 1.00 | 1.00 | 1.00 | ||
Baseline health (self-reported) | |||||
Duke Social Support Index | 0.95 (0.91,0.99) | 0.95 (0.91,0.99) | |||
Body mass index | |||||
Underweight (15– < 18 kg/m2) | 1.23 (0.80,1.89) | 1.23 (0.80,1.89) | |||
Normal (18– < 25 kg/m2) | 1.00 | 1.00 | |||
Overweight (25– < 30 kg/m2) | 0.98 (0.83,1.17) | 0.98 (0.82,1.17) | |||
Obese (>30–50 kg/m2) | 0.78 (0.64,0.95) | 0.77 (0.63,0.94) | |||
Smoking status | |||||
Current smoker | 1.00 | 1.00 | |||
Ex-smoker | 0.76 (0.57,1.03) | 0.78 (0.57,1.05) | |||
Never smoker | 0.76 (0.56,1.03) | 0.77 (0.57,1.05) | |||
Hospitalisation history (APDC, prior 6 years) | |||||
Previous CVD | |||||
Yes | 1.41 (1.06,1.88) | 1.44 (1.08,1.91) | |||
No | 1.00 | 1.00 | |||
Previous heart failure | |||||
Yes | 1.12 (0.94,1.32) | 1.11 (0.93,1.31) | |||
No | 1.00 | 1.00 | |||
Previous renal disease | |||||
Yes | 1.12 (0.89,1.40) | 1.11 (0.89,1.39) | |||
No | 1.00 | 1.00 | |||
Previous anaemia | |||||
Yes | 1.36 (1.13,1.62) | 1.36 (1.14,1.63) | |||
No | 1.00 | 1.00 | |||
Previous dementia | |||||
Yes | 0.66 (0.35,1.22) | 0.66 (0.36,1.22) | |||
No | 1.00 | 1.00 | |||
Index admission characteristics | |||||
Primary diagnosis | |||||
Yes | 0.94 (0.81,1.08) | 0.93 (0.80,1.07) | |||
No | 1.00 | 1.00 | |||
Current comorbidity (Charlson Index) | |||||
None | 1.00 | 1.00 | |||
Mild-moderate | 1.15 (0.98,1.35) | 1.15 (0.98,1.35) | |||
Severe | 1.25 (1.02,1.52) | 1.26 (1.03,1.54) | |||
Hospital characteristics | |||||
Hospital peer group | |||||
Principal referral | 1.00 | ||||
Major city | 0.92 (0.72,1.18) | ||||
District | 1.03 (0.81,1.31) | ||||
Community | 1.34 (0.99,1.81) | ||||
Private | 0.80 (0.63,1.01) | ||||
Others | 0.72 (0.48,1.09) | ||||
Heart failure service | |||||
Yes | 1.10 (0.93,1.31) | ||||
No | 1.00 |
Model | 1 | 2 | 3 | 4 | 5 |
---|---|---|---|---|---|
Random effects | |||||
Hospital variance | 0 | 0 | 0 | 0 | 0 |
ICC | 0 | 0 | 0 | 0 | 0 |
Fixed effects | Odds ratios | ||||
Sociodemographic | |||||
Age (years, at index admission) | |||||
45– < 75 | 1.00 | 1.00 | 1.00 | 1.00 | |
75– < 85 | 1.99 (1.24,3.20) | 1.97 (1.22,3.16) | 2.07 (1.26,3.40) | 2.04 (1.24,3.35) | |
≥ 85 | 3.33 (2.09,5.30) | 3.23 (2.00,5.20) | 3.30 (1.97,5.52) | 3.23 (1.93,5.41) | |
Sex | |||||
Male | 1.36 (1.00,1.84) | 1.34 (0.96,1.85) | 1.36 (0.96,1.93) | 1.36 (0.96,1.93) | |
Female | 1.00 | 1.00 | 1.00 | 1.00 | |
Marital status | |||||
Married | 1.02 (0.74,1.40) | 1.06 (0.77,1.47) | 1.06 (0.77,1.47) | ||
Not married | 1.00 | 1.00 | 1.00 | ||
Region of residence | |||||
Major cities | 1.00 | 1.00 | 1.00 | ||
Regional | 1.01 (0.72,1.41) | 1.06 (0.75,1.50) | 1.03 (0.72,1.46) | ||
Remote | 0.85 (0.55,1.31) | 0.90 (0.58,1.40) | 0.83 (0.51,1.38) | ||
Education | |||||
No school certificate | 1.00 | 1.00 | 1.00 | ||
School/trade/certificate/diploma | 0.90 (0.62,1.31) | 0.91 (0.62,1.32) | 0.91 (0.62,1.32) | ||
Tertiary degree | 1.18 (0.69,2.01) | 1.15 (0.67,1.98) | 1.16 (0.67,1.99) | ||
Private health insurance | |||||
Yes | 1.05 (0.77,1.43) | 1.10 (0.80,1.51) | 1.12 (0.80,1.56) | ||
No | 1.00 | 1.00 | 1.00 | ||
Baseline health (self-reported) | |||||
Duke Social Support Index | 0.97 (0.88,1.07) | 0.97 (0.88,1.07) | |||
BMI | |||||
Underweight | 1.68 (0.80,3.52) | 1.63 (0.77,3.42) | |||
Normal | 1.00 | 1.00 | |||
Overweight | 0.90 (0.62,1.30) | 0.90 (0.62,1.31) | |||
Obese | 0.62 (0.38,1.02) | 0.61 (0.37,1.01) | |||
Smoking status | |||||
Current smoker | 1.00 | 1.00 | |||
Ex-smoker | 0.50 (0.27,0.94) | 0.49 (0.27,0.92) | |||
Never smoker | 0.58 (0.31,1.09) | 0.57 (0.31,1.07) | |||
Hospitalisation history (APDC, prior 6 years) | |||||
Previous CVD | |||||
Yes | 0.73 (0.43,1.22) | 0.74 (0.44,1.24) | |||
No | 1.00 | 1.00 | |||
Previous heart failure | |||||
Yes | 1.23 (0.85,1.77) | 1.22 (0.84,1.76) | |||
No | 1.00 | 1.00 | |||
Previous renal disease | |||||
Yes | 0.73 (0.44,1.21) | 0.73 (0.44,1.21) | |||
No | 1.00 | 1.00 | |||
Previous anaemia | |||||
Yes | 1.17 (0.80,1.72) | 1.18 (0.81,1.72) | |||
No | 1.00 | 1.00 | |||
Previous dementia | |||||
Yes | 1.31 (0.50,3.40) | 1.30 (0.50,3.36) | |||
No | 1.00 | 1.00 | |||
Index admission characteristics | |||||
Primary diagnosis | |||||
Yes | 0.52 (0.36,0.73) | 0.51 (0.36,0.72) | |||
No | 1.00 | 1.00 | |||
Current comorbidity (Charlson Index) | |||||
None | 1.00 | 1.00 | |||
Mild-moderate | 1.42 (0.99,2.02) | 1.42 (0.99,2.02) | |||
Severe | 2.64 (1.80,3.88) | 2.68 (1.82,3.94) | |||
Hospital characteristics | |||||
Hospital peer group | |||||
Principal referral | 1.00 | ||||
Major city | 1.32 (0.84,2.08) | ||||
District | 1.26 (0.76,2.08) | ||||
Community | 1.11 (0.56,2.22) | ||||
Private | 0.96 (0.59,1.55) | ||||
Others | 0.61 (0.24,1.56) | ||||
Heart failure service | |||||
Yes | 0.90 (0.62,1.29) | ||||
No | 1.00 |