Table 1. Baseline Cohort Characteristics by Treatment Group.
| Characteristic | No. (%) of patients | ||||
|---|---|---|---|---|---|
| All (N = 19 529) | First-line treatment group | ||||
| Platinum/pemetrexed (n = 5159) | Platinum/taxane (n = 9866) | Pembrolizumab (n = 3079) | Platinum/pemetrexed/pembrolizumab (n = 1425) | ||
| Age at the index lung cancer event, y | |||||
| 66-69 | 4963 (25) | 1538 (30) | 2430 (25) | 595 (19) | 400 (28) |
| 70-79 | 11 012 (56) | 2921 (57) | 5680 (58) | 1571 (51) | 840 (59) |
| 80-89 | 3554 (18) | 700 (14) | 1756 (18) | 913 (30) | 185 (13) |
| Sex | |||||
| Male | 10 509 (54) | 2623 (51) | 5641 (57) | 1502 (49) | 743 (52) |
| Female | 9020 (46) | 2536 (49) | 4225 (43) | 1577 (51) | 682 (48) |
| Race/ethnicity | |||||
| Non-Hispanic | |||||
| White | 17 305 (89) | 4555 (88) | 8734 (89) | 2738 (89) | 1278 (90) |
| Black | 1395 (7) | 352 (7) | 773 (8) | 184 (6) | 86 (6) |
| Hispanic | 106 (1) | 35 (1) | 46 (0.5) | 19 (1) | NAa |
| Other | 723 (4) | 217 (4) | 313 (3) | 138 (4) | NAa |
| Medicaid enrollment | |||||
| No | 14 993 (77) | 4174 (81) | 7243 (73) | 2413 (78) | 1163 (82) |
| Yes | 4536 (23) | 985 (19) | 2623 (27) | 666 (22) | 262 (18) |
| Median household income in the census tract of residence, quintile | |||||
| Lowest 20% | 3905 (20) | 892 (17) | 2219 (22) | 551 (18) | 243 (17) |
| 20%-40% | 3906 (20) | 924 (18) | 2154 (22) | 559 (18) | 269 (19) |
| 40%-60% | 3906 (20) | 998 (19) | 2017 (20) | 604 (20) | 287 (20) |
| 60%-80% | 3905 (20) | 1068 (21) | 1883 (19) | 650 (21) | 304 (21) |
| Highest 20% | 3907 (20) | 1277 (25) | 1593 (16) | 715 (23) | 322 (23) |
| Urban/rural status of patient’s county | |||||
| Missing | 0 | 0 | 0 | 0 | 0 |
| Large metropolitan | 8031 (41) | 2410 (47) | 3604 (37) | 1363 (44) | 654 (46) |
| Metropolitan | 6822 (35) | 1722 (33) | 3579 (36) | 1073 (35) | 448 (31) |
| Urban | 1668 (9) | 379 (7) | 953 (10) | 227 (7) | 109 (8) |
| Less urban | 2417 (12) | 524 (10) | 1397 (14) | 331 (11) | 165 (12) |
| Rural | 591 (3) | 124 (2) | 333 (3) | 85 (3) | 49 (3) |
| Date of initial systematic lung cancer treatment | |||||
| 2016 first quarter | 1071 (5) | 422 (8) | 641 (6) | NAa | NAa |
| 2016 second quarter | 1780 (9) | 668 (13) | 1108 (11) | NAa | NAa |
| 2016 third quarter | 1792 (9) | 692 (13) | 1094 (11) | NAa | NAa |
| 2016 fourth quarter | 1674 (9) | 582 (11) | 918 (9) | 173 (6) | NAa |
| 2017 first quarter | 1883 (10) | 569 (11) | 930 (9) | 384 (12) | NAa |
| 2017 second quarter | 1902 (10) | 432 (8) | 929 (9) | 435 (14) | 106 (7) |
| 2017 third quarter | 1865 (10) | 389 (8) | 903 (9) | 388 (13) | 185 (13) |
| 2017 fourth quarter | 1782 (9) | 402 (8) | 806 (8) | 382 (12) | 192 (13) |
| 2018 first quarter | 1909 (10) | 400 (8) | 819 (8) | 464 (15) | 226 (16) |
| 2018 second quarter | 1916 (10) | 330 (6) | 872 (9) | 399 (13) | 315 (22) |
| 2018 third quarter | 1883 (10) | 266 (5) | 818 (8) | 416 (14) | 383 (27) |
| 2018 fourth quarterb | 72 (0.4) | NA | NA | NA | NA |
| Adults with college degree in patient’s zip code of residence, quintile | |||||
| Lowest 20% | 3931 (20) | 851 (16) | 2312 (23) | 513 (17) | 255 (18) |
| 20%-40% | 3914 (20) | 958 (19) | 2116 (21) | 567 (18) | 273 (19) |
| 40%-60% | 3880 (20) | 1020 (20) | 1988 (20) | 605 (20) | 267 (19) |
| 60%-80% | 3912 (20) | 1126 (22) | 1855 (19) | 636 (21) | 295 (21) |
| Highest 20% | 3892 (20) | 1204 (23) | 1595 (16) | 758 (25) | 335 (24) |
| RSI at baseline, quintile | |||||
| Lowest 20% | 3905 (20) | 1061 (21) | 2227 (23) | 384 (12) | 233 (16) |
| 20%-40% | 3907 (20) | 970 (19) | 2200 (22) | 473 (15) | 264 (19) |
| 40%-60% | 3905 (20) | 1052 (20) | 1958 (20) | 598 (19) | 297 (21) |
| 60%-80% | 3907 (20) | 1046 (20) | 1848 (19) | 702 (23) | 311 (22) |
| Highest 20% | 3905 (20) | 1030 (20) | 1633 (17) | 922 (30) | 320 (22) |
Abbreviations: NA, not applicable; RSI, Risk Stratification Index.
a
Cell information suppressed consistent with Centers for Medicare & Medicaid Services cell size suppression policy.
b
Data for 2018 fourth quarter are incomplete.