Table 1. Characteristics of Patients by Perioperative Gabapentin Use Before and After Propensity Score Matching.
| Characteristic | Before propensity score matching | After propensity score matchinga | ||||
|---|---|---|---|---|---|---|
| Gabapentin use (n = 119 087)b | No gabapentin use (n = 848 460)b | SMD | Gabapentin use (n = 118 936)b | No gabapentin use (n = 118 936)b | SMD | |
| Age, mean (SD), y | 74.5 (6.7) | 76.4 (7.5) | –0.27 | 74.5 (6.7) | 74.4 (6.8) | 0.01 |
| Sex | ||||||
| Female | 74 627 (62.7) | 501 934 (59.2) | 0.07 | 74 525 (62.7) | 74 682 (62.8) | <0.01 |
| Male | 44 460 (37.3) | 346 526 (40.8) | −0.07 | 44 411 (37.3) | 44 254 (37.2) | <0.01 |
| Race and ethnicity | ||||||
| Black | 9231 (7.8) | 62 406 (7.4) | 0.01 | 9215 (7.7) | 9274 (7.8) | <0.01 |
| White | 98 562 (82.8) | 697 010 (82.2) | 0.02 | 98 438 (82.8) | 98 490 (82.8) | <0.01 |
| Otherc | 11 294 (9.5) | 89 044 (10.5) | –0.03 | 11 283 (9.5) | 11 172 (9.4) | <0.01 |
| Insurance type | ||||||
| Medicare | 106 860 (89.7) | 764 277 (90.1) | –0.01 | 106 727 (89.7) | 106 931 (89.9) | –0.01 |
| Medicaid | 1704 (1.4) | 10 998 (1.3) | 0.01 | 1699 (1.4) | 1618 (1.4) | 0.01 |
| Commercial | 8115 (6.8) | 58 163 (6.9) | <0.01 | 8106 (6.8) | 8078 (6.8) | <0.01 |
| Other | 1270 (1.1) | 7806 (0.9) | 0.01 | 1269 (1.1) | 1213 (1.0) | <0.01 |
| Uninsured | 1138 (1.0) | 7216 (0.9) | 0.01 | 1135 (1) | 1096 (0.9) | <0.01 |
| Hospital admission type | ||||||
| Elective | 93 674 (78.7) | 422 262 (49.8) | 0.63 | 93 523 (78.6) | 94 096 (79.1) | –0.01 |
| Urgent | 7368 (6.2) | 85 342 (10.1) | –0.14 | 7368 (6.2) | 7258 (6.1) | <0.01 |
| Emergent | 16 780 (14.1) | 327 675 (38.6) | –0.58 | 16 780 (14.1) | 16 256 (13.7) | 0.01 |
| Other | 1265 (1.1) | 13 181 (1.6) | –0.04 | 1265 (1.1) | 1326 (1.1) | <0.01 |
| Surgery type | ||||||
| Cardiac | 624 (0.5) | 16 391 (1.9) | –0.13 | 624 (0.5) | 556 (0.5) | 0.01 |
| Gastrointestinal | 15 866 (13.3) | 195 395 (23.0) | –0.25 | 15 863 (13.3) | 15 249 (12.8) | 0.02 |
| Genitourinary | 2523 (2.1) | 48 933 (5.8) | –0.19 | 2523 (2.1) | 2461 (2.1) | <0.01 |
| Neurological | 3096 (2.6) | 12 085 (1.4) | 0.08 | 3088 (2.6) | 3217 (2.7) | –0.01 |
| Orthopedic | 91 014 (76.4) | 498 258 (58.7) | 0.39 | 90 875 (76.4) | 91 315 (76.8) | –0.01 |
| Thoracic | 1549 (1.3) | 20 288 (2.4) | –0.08 | 1549 (1.3) | 1585 (1.3) | <0.01 |
| Vascular | 4415 (3.7) | 57 110 (6.7) | –0.14 | 4414 (3.7) | 4553 (3.8) | –0.01 |
| CCI score, mean (SD)d | 1.2 (2.2) | 1.8 (2.6) | –0.24 | 1.2 (2.2) | 1.1 (2.2) | 0.01 |
| Comorbidities | ||||||
| Any tumor | 13 798 (11.6) | 137 070 (16.2) | –0.13 | 13 788 (11.6) | 13 474 (11.3) | 0.01 |
| Chronic pulmonary disease | 25 542 (21.4) | 180 276 (21.2) | <0.01 | 25 490 (21.4) | 25 196 (21.2) | 0.01 |
| Congestive heart failure | 12 625 (10.6) | 121 638 (14.3) | –0.11 | 12 607 (10.6) | 12 551 (10.6) | <0.01 |
| Dementia | 3311 (2.8) | 49 664 (5.9) | –0.15 | 3310 (2.8) | 3149 (2.6) | 0.01 |
| Kidney failure | 2846 (2.4) | 45 468 (5.4) | –0.15 | 2846 (2.4) | 2856 (2.4) | <0.01 |
| Analgesic drugs | ||||||
| Acetaminophen | 102 013 (85.7) | 598 803 (70.6) | 0.37 | 101 867 (85.6) | 102 237 (86.0) | –0.01 |
| Cyclooxygenase-2 inhibitor | 24 837 (20.9) | 65 370 (7.7) | 0.38 | 24 764 (20.8) | 24 432 (20.5) | 0.01 |
| NSAID | 26 822 (22.5) | 124 966 (14.7) | 0.20 | 26 771 (22.5) | 26 921 (22.6) | <0.01 |
| Opioid | 109 389 (91.9) | 686 293 (80.9) | 0.32 | 109 238 (91.8) | 109 561 (92.1) | –0.01 |
| Opioid dose, MME/d, mean (SD) | 7.6 (6.1) | 5.8 (5.6) | 0.31 | 7.6 (6.1) | 7.7 (6.3) | <0.01 |
| Psychoactive drugs | ||||||
| Alzheimer disease agents | 2943 (2.5) | 29 494 (3.5) | –0.06 | 2942 (2.5) | 2831 (2.4) | 0.01 |
| Antidepressants | 29 772 (25.0) | 141 942 (16.7) | 0.20 | 29 659 (24.9) | 29 720 (25.0) | <0.01 |
| Anxiolytics | 84 529 (71.0) | 525 736 (62.0) | 0.19 | 84 411 (71.0) | 84 662 (71.2) | <0.01 |
| Sedatives | 7805 (6.6) | 42 346 (5.0) | 0.07 | 7784 (6.5) | 7762 (6.5) | <0.01 |
| Hospital characteristic | ||||||
| Teaching | 55 930 (47.0) | 367 537 (43.3) | 0.07 | 55 843 (47.0) | 55 577 (46.7) | <0.01 |
| Urban | 107 083 (89.9) | 750 848 (88.5) | 0.05 | 106 944 (89.9) | 106 680 (89.7) | 0.01 |
| Geographic region | ||||||
| Northeast | 27 825 (23.4) | 182 705 (21.5) | 0.04 | 27 776 (23.4) | 27 529 (23.1) | <0.01 |
| Midwest | 18 704 (15.7) | 135 019 (15.9) | –0.01 | 18 690 (15.7) | 18 639 (15.7) | <0.01 |
| South | 50 055 (42.0) | 382 716 (45.1) | –0.06 | 50 006 (42.0) | 50 672 (42.6) | –0.01 |
| West | 22 503 (18.9) | 148 020 (17.4) | 0.04 | 22 464 (18.9) | 22 096 (18.6) | 0.01 |
Abbreviations: CCI, combined comorbidity index; MME, morphine milligram equivalent; NSAID, nonsteroidal anti-inflammatory drug; SMD, standardized mean difference.
a
The propensity score model included demographic information, insurance type, admission characteristics, surgery type, combined comorbidity score, comorbidities, inpatient medication use and procedures before or on postoperative day 2, hospital-level characteristics, geographic region, and calendar year.
b
Data are reported as number (percentage) of patients unless otherwise indicated.
c
Included individuals who identified as American Indian, Asian/Pacific Islander, Hispanic, or other.
d
Scores range from −2 to 26, with higher scores indicating greater risk of death.