Hierarchical linear model (random intercept model) for OPCAB LOS
| Characteristics | Multiplier* (95% CI) | p Value | |
|---|---|---|---|
| Patient characteristics | |||
| Intercept, days | 18.0 | (16.5 to 19.6) | <0.001 |
| Preoperative LOS (days) (ref ≤3) | |||
| 4–6 | 1.137 | (1.109 to 1.166) | <0.001 |
| 7–9 | 1.284 | (1.246 to 1.323) | <0.001 |
| ≥10 | 1.516 | (1.462 to 1.572) | <0.001 |
| Age (years) (ref <65) | |||
| 65–74 | 1.038 | (1.015 to 1.061) | 0.001 |
| ≥75 | 1.093 | (1.065 to 1.122) | <0.001 |
| Sex (ref male) | |||
| Female | 1.043 | (1.017 to 1.070) | 0.001 |
| Smoking status (ref not smoking) | |||
| Smoking | 0.978 | (0.958 to 0.999) | 0.040 |
| Use of IABP (ref no) | |||
| Yes | 1.039 | (1.002 to 1.076) | 0.041 |
| Renal failure with dialysis | 1.099 | (1.056 to 1.143) | <0.001 |
| Renal failure without dialysis | 1.079 | (1.032 to 1.131) | 0.001 |
| Diabetes, complicated | 1.050 | (1.020 to 1.083) | 0.005 |
| Diabetes, uncomplicated | 1.031 | (1.009 to 1.054) | 0.005 |
| Cardiac arrhythmias | 1.051 | (1.018 to 1.086) | 0.003 |
| Peptic ulcer disease excluding bleeding | 0.971 | (0.939 to 1.004) | 0.082 |
| Deficiency anaemia | 0.934 | (0.886 to 0.984) | 0.012 |
| Liver disease | 1.071 | (1.005 to 1.143) | 0.034 |
| Coagulopathy | 1.112 | (1.020 to 1.215) | 0.016 |
| Hypothyroidism | 1.110 | (0.997 to 1.237) | 0.056 |
| Hypertension, complicated | 1.113 | (0.966 to 1.289) | 0.139 |
| Duration of anaesthesia (hours) (ref ≤4) | |||
| 6.5–8 | 1.026 | (0.994 to 1.055) | 0.107 |
| ≥8.5 | 1.071 | (1.028 to 1.135) | 0.001 |
| Hospital characteristics | |||
| Teaching | 1.075 | (1.001 to 1.144) | 0.046 |
| Private not-for-profit ownership | 1.013 | (0.961 to 1.068) | 0.622 |
| Hospital index charge (ref 10:1) | |||
| 7:1 | 1.044 | (0.974 to 1.122) | 0.225 |
| Size (ref ≤449) | |||
| 450–799 | 1.005 | (0.950 to 1.067) | 0.862 |
| ≥800 | 0.960 | (0.881 to 1.055) | 0.350 |
| OPCAB hospital volume (ref ≤14) | |||
| 15–29 | 0.947 | (0.897 to 1.001) | 0.053 |
| 30–59 | 0.988 | (0.927 to 1.054) | 0.719 |
| ≥60 | 0.824 | (0.748 to 0.909) | <0.001 |
*Exponentiated parameter estimates from a log model.
IABP, intra-aortic balloon pumping; LOS, length of stay; OPCAB, off-pump coronary artery bypass grafting.