Table 1.
Baseline characteristics.
| Total (N = 59 510) | Unexposed (to immunotherapy) (N = 50 739) | Exposed (to immunotherapy) (8771) | P value | |
|---|---|---|---|---|
| Age at index date | ||||
| Mean (SD) | 68.33 ± 11.34 | 68.84 ± 11.33 | 65.37 ± 10.97 | <.001 |
| Median (IQR) | 69 (61-77) | 69 (61-77) | 66 (59-73) | <.001 |
| Age <65 | 21 417 (36.0%) | 17 505 (34.5%) | 3912 (44.6%) | <.001 |
| Age ≥65 | 38 093 (64.0%) | 33 234 (65.5%) | 4859 (55.4%) | |
| Female, n (%) | 24 756 (41.6%) | 21, 294 (42.0%) | 3462 (39.5%) | <.001 |
| Income quintile, N (%) | ||||
| Quintile 1 | 13 606 (22.9%) | 11 967 (23.6%) | 1639 (18.7%) | <.001 |
| Quintile 2 | 12 964 (21.8%) | 11 126 (21.9%) | 1838 (21.0%) | |
| Quintile 3 | 11 652 (19.6%) | 9874 (19.5%) | 1778 (20.3%) | |
| Quintile 4 | 10 886 (18.3%) | 9146 (18.0%) | 1740 (19.8%) | |
| Quintile 5 | 10 213 (17.2%) | 8459 (16.7%) | 1754 (20.0%) | |
| Rural, yes, n (%) | 8845 (14.9%) | 7556 (14.9%) | 1289 (14.7%) | .704 |
| Year of cohort entry, n (%) | ||||
| 2011 | 7195 (12.1%) | 6956 (13.7%) | 239 (2.7%) | <.001 |
| 2012 | 7363 (12.4%) | 6980 (13.8%) | 383 (4.4%) | |
| 2013 | 7481 (12.6%) | 6966 (13.7%) | 515 (5.9%) | |
| 2014 | 7216 (12.1%) | 6526 (12.9%) | 690 (7.9%) | |
| 2015 | 7059 (11.9%) | 6057 (11.9%) | 1002 (11.4%) | |
| 2016 | 7105 (11.9%) | 5853 (11.5%) | 1252 (14.3%) | |
| 2017 | 6913 (11.6%) | 5355 (10.6%) | 1558 (17.8%) | |
| 2018 | 5681 (9.5%) | 3920 (7.7%) | 1761 (20.1%) | |
| 2019 | 3497 (5.9%) | 2126 (4.2%) | 1371 (15.6%) | |
| Local Health Integration Network for Ontario (LHIN), n (%) | ||||
| A | 3813 (6.4%) | 3272 (6.4%) | 541 (6.2%) | <.001 |
| B | 5238 (8.8%) | 4539 (8.9%) | 699 (8.0%) | |
| C | 3151 (5.3%) | 2736 (5.4%) | 415 (4.7%) | |
| D | 7321 (12.3%) | 6270 (12.4%) | 1051 (12.0%) | |
| E | 2448 (4.1%) | 1998 (3.9%) | 450 (5.1%) | |
| F | 3512 (5.9%) | 2929 (5.8%) | 583 (6.6%) | |
| G | 4226 (7.1%) | 3677 (7.2%) | 549 (6.3%) | |
| H | 5870 (9.9%) | 4951 (9.8%) | 919 (10.5%) | |
| I | 6692 (11.2%) | 5700 (11.2%) | 992 (11.3%) | |
| J | 3401 (5.7%) | 2872 (5.7%) | 529 (6.0%) | |
| K | 6280 (10.6%) | 5343 (10.5%) | 937 (10.7%) | |
| L | 2513 (4.2%) | 2099 (4.1%) | 414 (4.7%) | |
| M | 3814 (6.4%) | 3272 (6.4%) | 542 (6.2%) | |
| N | 1231 (2.1%) | 1081 (2.1%) | 150 (1.7%) | |
| Tumor site, n (%) | ||||
| Head and neck | 7253 (12.2%) | 6775 (13.4%) | 478 (5.4%) | <.001 |
| Melanoma | 3838 (6.4%) | 1845 (3.6%) | 1993 (22.7%) | |
| Kidney | 3387 (5.7%) | 2499 (4.9%) | 888 (10.1%) | |
| Bladder | 3708 (6.2%) | 3137 (6.2%) | 571 (6.5%) | |
| Lung | 41 324 (69.4%) | 36 483 (71.9%) | 4841 (55.2%) | |
| More than one (stage 4) cancer diagnosis, n (%) | 537 (0.9%) | 505 (1.0%) | 32 (0.4%) | <.001 |
| Teaching | 16 685 (28.0%) | 12 823 (25.3%) | 3862 (44.0%) | |
| Other/missing | 28 924 (48.6%) | 27 575 (54.3%) | 1349 (15.4%) | |
| Diagnosis cancer center level, n (%) | ||||
| 1 | 19 769 (33.2%) | 16 917 (33.3%) | 2852 (32.5%) | <.001 |
| 2 | 15 078 (25.3%) | 12 837 (25.3%) | 2241 (25.6%) | |
| 3 | 14 221 (23.9%) | 12 234 (24.1%) | 1987 (22.7%) | |
| 4 | 10 386 (17.5%) | 8715 (17.2%) | 1671 (19.1%) | |
| Other/missing | 56 (0.1%) | 36 (0.1%) | 20 (0.2%) | |
| Radiation therapy, Yes, n (%) | 33 924 (57.0%) | 28 024 (55.2%) | 5900 (67.3%) | <.001 |
| Hospitalizations, Yes (%) | 40 328 (67.8%) | 35 377 (69.7%) | 4951 (56.4%) | <.001 |
| IO regimen part of clinical trial, for patients who had the outcome, n (%) | N/A | N/A | 637 (7.3%) | N/A |
| Charlson Comorbidty Index in the previous 5 years, n (%) | ||||
| 0 | 7857 (13.2%) | 6741 (13.3%) | 1116 (12.7%) | <.001 |
| 1 | 4961 (8.3%) | 4392 (8.7%) | 569 (6.5%) | |
| 2 | 3891 (6.5%) | 3423 (6.7%) | 468 (5.3%) | |
| 3+ | 5309 (8.9%) | 4834 (9.5%) | 475 (5.4%) | |
| No hospitalizations | 37 492 (63.0%) | 31 349 (61.8%) | 6143 (70.0%) | |
| IO drug type, n (%) | ||||
| Atezolizumab | N/A | N/A | 267 (3.0%) | N/A |
| Avelumab | N/A | N/A | 48 (0.5%) | |
| Combination | N/A | N/A | 754 (8.6%) | |
| Durvalumab | N/A | N/A | 238 (2.7%) | |
| Ipilimumab | N/A | N/A | 423 (4.8%) | |
| Nivolumab | N/A | N/A | 3283 (37.4%) | |
| Pembrolizumab | N/A | N/A | 3647 (41.6%) | |
| De novo stage 4 cancer, n (%) | 43 297 (72.8%) | 39 849 (78.5%) | 3448 (39.3%) | <.001 |
*index date: date of cancer diagnosis. Abbreviations: IO, immunotherapy; NA, not applicable.