TABLE 2.
Quality of the Matches for Representative Covariates
| Selected Covariates (percent unless noted) | All New Surgeon (Patients not Matched) | Matched New Surgeon Patients | Experienced Surgeon Patients Matched for: | All Experienced Surgeon Patients After Surgeon Pairing (patients not matched) | All Experienced Surgeon Patients Before Surgeon Pairing (patients not matched) | |||
|---|---|---|---|---|---|---|---|---|
| Baseline + Operation + Emerg. + Risk Factors | Baseline + Operation + Emerg. | Baseline + Operation | Baseline | |||||
| Number of Surgeons | 2,119 | 1,820 | 1,820 | 1,820 | 1,820 | 1,820 | 1,820 | 8,503 |
| Number of Patients | 68,036 | 18,200 | 18,200 | 18,200 | 18,200 | 18,200 | 203,113 | 694,165 |
| Year of admission (mean) | 2011.4 | 2011.5 | 2011.4 | 2011.5 | 2011.5 | 2011.5 | 2011.0 | 2011.0 |
| Principal Procedure Categories | ||||||||
| Appendectomy | 5.1 | 5.3 | 5.3 | 5.3 | 5.3 | 3.9 | 3.9 | 3.7 |
| Cholecystectomy | 31.0 | 29.8 | 29.8 | 29.8 | 29.8 | 24.5 | 25.4 | 23.1 |
| Hernia Groin - Open | 3.4 | 3.6 | 3.6 | 3.6 | 3.6 | 3.4 | 3.2 | 3.1 |
| Mastectomy | 1.3 | 1.4 | 1.4 | 1.4 | 1.4 | 3.0 | 2.6 | 3.9 |
| Pancreatectomy | 0.7 | 0.7 | 0.7 | 0.7 | 0.7 | 1.7 | 1.8 | 2.5 |
| Small Bowel Resection | 8.3 | 8.3 | 8.3 | 8.3 | 8.3 | 6.9 | 6.6 | 6.1 |
| Stomach Anti-Reflux | 0.4 | 0.3 | 0.3 | 0.3 | 0.3 | 0.7 | 1.0 | 0.9 |
| Thyroidectomy Partial | 0.2 | 0.3 | 0.3 | 0.3 | 0.3 | 0.6 | 0.6 | 1.1 |
| Hip Repair | 23.2 | 29.7 | 29.7 | 29.7 | 29.7 | 17.1 | 10.4 | 9.0 |
| Hip Replacement | 46.8 | 50.1 | 50.1 | 50.1 | 50.1 | 37.4 | 35.5 | 33.4 |
| Hip Replacement Revision | 3.7 | 2.0 | 2.0 | 2.0 | 2.0 | 3.0 | 3.5 | 3.2 |
| Knee Replacement | 23.2 | 16.8 | 16.8 | 16.8 | 16.8 | 39.8 | 47.3 | 51.0 |
| Knee Replacement Revision | 3.1 | 1.5 | 1.5 | 1.5 | 1.5 | 2.8 | 3.4 | 3.5 |
| Emergent Admission | 47.2 | 53.9 | 53.9 | 53.9 | 43.0 | 34.7 | 25.8 | 23.0 |
| Risk Factors & Patient Demographics | ||||||||
| Age at Admission (years, mean) | 78.7 | 79.0 | 79.1 | 78.2 | 77.2 | 77.0 | 76.7 | |
| Age 65–69 | 18.1 | 17.2 | 16.9 | 19.0 | 21.6 | 21.6 | 22.7 | |
| Age 85+ | 24.6 | 25.8 | 26.7 | 24.1 | 21.9 | 17.8 | 16.3 | 15.0 |
| Past Admission in Last 6 Months | 24.0 | 25.6 | 24.1 | 24.5 | 24.1 | 22.9 | 19.3 | 18.0 |
| Probability of 30-day Death | 4.8 | 5.6 | 5.5 | 5.2 | 4.7 | 4.2 | 3.0 | 2.7 |
| Comorbidity Count (mean) | 4.0 | 4.1 | 4.0 | 4.0 | 4.0 | 3.9 | 3.5 | 3.5 |
| Comorbidities | ||||||||
| Congestive Heart Failure | 20.5 | 22.2 | 21.4 | 20.5 | 19.9 | 18.2 | 15.2 | 14.0 |
| Past Myocardial Infarction | 9.9 | 10.4 | 9.1 | 9.9 | 10.0 | 9.5 | 8.3 | 8.0 |
| Past Arrhythmia | 29.2 | 30.5 | 29.8 | 30.3 | 30.0 | 29.2 | 26.9 | 26.7 |
| Diabetes | 31.8 | 32.5 | 32.9 | 31.9 | 32.0 | 32.2 | 30.1 | 29.8 |
| Renal Dysfunction | 22.7 | 25.2 | 24.8 | 22.6 | 21.5 | 20.8 | 16.4 | 15.5 |
| Renal Failure | 5.0 | 5.6 | 5.0 | 5.2 | 5.1 | 4.8 | 3.7 | 3.5 |
| Cancer | 33.6 | 36.0 | 37.9 | 37.4 | 37.6 | 38.7 | 34.4 | 34.4 |
| Dementia | 19.9 | 21.2 | 20.5 | 18.4 | 16.7 | 13.8 | 11.7 | 10.7 |
| Stroke | 14.7 | 15.9 | 14.4 | 15.1 | 14.1 | 13.0 | 11.0 | 10.5 |