Outcome differences associated with non-first versus first procedure groups in the on-pump and off-pump CABG cohorts
| Outcome | On-pump CABG cohort (n=10 109) | Off-pump CABG cohort (n=11 757) | ||||||
| First procedure (n=8480) | Non-first procedure (n=1629) | RRadj*/ORadj† (95% CI) | P value | First procedure (n=8279) | Non-first procedure (n=3478) | RRadj*/ORadj† (95% CI) | P value | |
| AEC, n (%)* | 0.90 (0.77 to 1.06) | 0.19 | 1.29 (1.13 to 1.47) | <0.001 | ||||
| One event | 984 (11.6) | 165 (10.1) | 658 (7.9) | 319 (9.2) | ||||
| Two events | 71 (0.8) | 17 (1.0) | 44 (0.5) | 28 (0.8) | ||||
| Three events | 13 (0.2) | 3 (0.2) | 3 (0.0) | 5 (0.1) | ||||
| Four events | 2 (0.0) | 0 (0.0) | 1 (0.0) | 0 (0.0) | ||||
| Death, n (%) | 32 (0.4) | 10 (0.6) | 1.44 (0.79 to 2.62) | 0.23 | 16 (0.2) | 12 (0.3) | 2.01 (0.94 to 4.27) | 0.07 |
| MI, n (%) | 379 (4.5) | 71 (4.4) | 0.84 (0.64 to 1.09) | 0.19 | 204 (2.5) | 114 (3.3) | 1.43 (1.13 to 1.81) | 0.003 |
| Stroke, n (%) | 98 (1.2) | 11 (0.7) | 0.57 (0.31 to 1.06) | 0.08 | 57 (0.7) | 40 (1.2) | 1.73 (1.18 to 2.53) | 0.005 |
| AKI, n (%) | 559 (6.6) | 98 (6.0) | 0.93 (0.72 to 1.21) | 0.60 | 362 (4.4) | 178 (5.1) | 1.23 (1.00 to 1.51) | 0.054 |
| Reoperation, n (%) | 105 (1.2) | 18 (1.1) | 0.83 (0.50 to 1.38) | 0.48 | 120 (1.4) | 46 (1.3) | 0.92 (0.64 to 1.32) | 0.65 |
AEC indicates adverse events composite, which is defined as the number of any adverse events that occurred, including death, myocardial infarction, stroke, acute kidney injury or reoperation.
*For the adverse events composite (AEC, count variable), the ‘n (%)’ presents the number of patients with given number of events and the percentage of those patients among specific procedure group. A mixed-effects model with a Poisson link function and surgeon-specific random intercepts is fitted, adjusting for the patient risk factors and surgeon characteristics mentioned in the Methods section and listed in online supplemental table 2. The adjusted rate ratio (non-first vs first) is estimated, and when it achieves a statistically significant level of 0.05, the p value is in bold.
†For every individual event (binary variable; ie, death, MI, stroke, AKI and reoperation), a mixed-effects model with a logit link function and surgeon-specific random intercepts is fitted, also adjusting for the patient and surgeon characteristics listed in online supplemental table 2. The adjusted OR (non-first vs first) for each outcome is estimated, and when it achieves a statistically significant level of 0.05, the p value is in bold.
AKI, acute kidney injury; CABG, coronary artery bypass grafting; MI, myocardial infarction; ORadj, adjusted OR; RRadj, adjusted rate ratio.