Baseline characteristics of the study cohort population who had surgery* in Ontario from Jan. 1, 2007, to Dec. 31, 2015, stratified by surgeon age
| Characteristic | No. (%) of patients† | Standardized difference | |
|---|---|---|---|
| Surgeon age (< 65 yr) n = 1 090 243 | Surgeon age (≥ 65 yr) n = 69 433 | ||
| Patient | |||
| Age, yr | |||
| Mean ± SD | 58.80 ± 17.32 | 59.51 ± 16.50 | 0.04 |
| Median (IQR) | 60 (47–72) | 61 (48–72) | 0.04 |
| Sex | |||
| Female | 654 432 (60.0) | 41 312 (59.5) | 0.01 |
| Male | 435 811 (40.0) | 28 121 (40.5) | 0.01 |
| Income quintile | |||
| 1 (lowest) | 203 357 (18.7) | 13 620 (19.6) | 0.02 |
| 2 | 216 626 (19.9) | 14 136 (20.4) | 0.01 |
| 3 | 217 754 (20.0) | 13 846 (19.9) | 0 |
| 4 | 228 148 (20.9) | 13 851 (19.9) | 0.02 |
| 5 (highest) | 219 653 (20.1) | 13 672 (19.7) | 0.01 |
| Missing | 4705 (0.4) | 308 (0.4) | 0 |
| Rurality‡ | |||
| Urban | 926 799 (85.0) | 57 328 (82.6) | 0.07 |
| Rural | 162 506 (14.9) | 12 054 (17.4) | 0.07 |
| Missing | 938 (0.1) | 51 (0.1) | 0 |
| ADG category | |||
| 0–5 | 291 564 (26.7) | 18 562 (26.7) | 0 |
| 6–7 | 262 557 (24.1) | 17 064 (24.6) | 0.01 |
| 8–10 | 326 048 (29.9) | 21 075 (30.4) | 0.01 |
| ≥ 11 | 210 074 (19.3) | 12 732 (18.3) | 0.02 |
| Year of surgery | |||
| 2007 | 135 552 (12.4) | 7113 (10.2) | 0.07 |
| 2008 | 129 867 (11.9) | 6673 (9.6) | 0.07 |
| 2009 | 125 763 (11.5) | 7213 (10.4) | 0.04 |
| 2010 | 120 517 (11.1) | 7544 (10.9) | 0.01 |
| 2011 | 119 427 (11.0) | 7531 (10.8) | 0 |
| 2012 | 116 606 (10.7) | 7678 (11.1) | 0.01 |
| 2013 | 117 000 (10.7) | 7937 (11.4) | 0.02 |
| 2014 | 113 908 (10.4) | 8414 (12.1) | 0.05 |
| 2015 | 111 603 (10.2) | 9330 (13.4) | 0.1 |
| Physician | |||
| Physician sex | |||
| Female | 142 869 (13.1) | 1250 (1.8) | 0.44 |
| Male | 947 374 (86.9) | 68 183 (98.2) | 0.44 |
| Years in practice | |||
| Mean ± SD | 14.24 ± 8.18 | 25.10 ± 5.21 | 1.58 |
| Median (IQR) | 15 (7–21) | 24 (21–28) | 1.57 |
| Surgical volume (quartiles) | |||
| 1 (lowest) | 269 844 (24.8) | 15 233 (21.9) | 0.07 |
| 2 | 283 846 (26.0) | 15 965 (23.0) | 0.07 |
| 3 | 269 036 (24.7) | 17 678 (25.5) | 0.02 |
| 4 (highest) | 267 517 (24.5) | 20 557 (29.6) | 0.11 |
| Specialty | |||
| Cardiothoracic surgery | 65 838 (6.0) | 2921 (4.2) | 0.08 |
| General surgery | 367 612 (33.7) | 17 112 (24.6) | 0.2 |
| Neurosurgery | 41 851 (3.8) | 4781 (6.9) | 0.14 |
| Obstetrics and gynecology | 125 775 (11.5) | 9167 (13.2) | 0.05 |
| Orthopedic surgery | 309 452 (28.4) | 21 581 (31.1) | 0.06 |
| Otolaryngology | 24 373 (2.2) | 2035 (2.9) | 0.04 |
| Plastic surgery | 61 379 (5.6) | 5463 (7.9) | 0.09 |
| Thoracic surgery | 12 092 (1.1) | 61 (0.1) | 0.13 |
| Urology | 78 085 (7.2) | 6233 (9.0) | 0.07 |
| Vascular surgery | 3786 (0.3) | 79 (0.1) | 0.05 |
| Hospital | |||
| Practice setting | |||
| Academic | 369 654 (33.9) | 29 174 (42.0) | 0.17 |
| Community | 720 589 (66.1) | 40 259 (58.0) | 0.17 |
Note: ADG = Aggregated Diagnosis Group, IQR = interquartile range, SD = standard deviation.
↵* Procedures included coronary artery bypass grafting, femoral-popliteal bypass, abdominal aortic aneurysm repair, appendectomy, cholecystectomy, gastric bypass, colon resection, liver resection, hysterectomy, anterior or posterior spinal decompression, anterior or posterior spinal arthrodesis, craniotomy for brain tumour, total knee replacement, total hip replacement, open repair of femoral neck or shaft fracture, total thyroidectomy, neck dissection, lung resection, radical cystectomy, radical prostatectomy, transurethral resection of prostate, carpal tunnel release, and breast reduction.
↵† Unless specified otherwise.
↵‡ Defined using standard ICES methodology that relies on residential postal codes.