Table 1.
Baseline Characteristics By Implant Volume
| Low (3–8) (N=5002) |
Medium (9–24) (N=4388) |
High (25+) (N=4489) |
Total (N=13879) |
p-value | |
|---|---|---|---|---|---|
| Successful Trial, N(%) | 0.0292 | ||||
| No | 1834 (36.7%) | 1532 (34.9%) | 1532 (34.1%) | 4898 (35.3%) | |
| Yes | 3168 (63.3%) | 2856 (65.1%) | 2957 (65.9%) | 8981 (64.7%) | |
| Explant, N(%) | 0.0257 | ||||
| No | 4569 (91.3%) | 4052 (92.3%) | 4074 (90.8%) | 12695 (91.5%) | |
| Yes | 433 (8.7%) | 336 (7.7%) | 415 (9.2%) | 1184 (8.5%) | |
| Inpatient, N(%) | 0.0906 | ||||
| Inpatient | 92 (1.8%) | 101 (2.3%) | 111 (2.5%) | 304 (2.2%) | |
| Outpatient | 4910 (98.2%) | 4287 (97.7%) | 4378 (97.5%) | 13575 (97.8%) | |
| Charlson comorbidity score, N(%) | 0.0002 | ||||
| N | 4944 | 4333 | 4427 | 13704 | |
| Mean (SD) | 0.9 (1.3) | 0.9 (1.3) | 1.0 (1.4) | 0.9 (1.3) | |
| Median | 0.0 | 0.0 | 0.0 | 0.0 | |
| Employment Status, N(%) | <0.0001 | ||||
| Active Full Time | 1555 (31.1%) | 1114 (25.4%) | 635 (14.1%) | 3304 (23.8%) | |
| Retiree | 977 (19.6%) | 581 (13.2%) | 404 (8.9%) | 1962 (14.2%) | |
| Other | 2470 (49.4%) | 2693 (61.5%) | 3450 (76.9) | 8613 (62.1%) | |
| Gender, N(%) | 0.4712 | ||||
| Male | 1887 (37.7%) | 1611 (36.7%) | 1645 (36.6%) | 5143 (37.1%) | |
| Female | 3115 (62.3%) | 2777 (63.3%) | 2844 (63.4%) | 8736 (62.9%) | |
| Age at SCS, N(%) | 0.0026 | ||||
| Mean (SD) | 53.0 (13.4) | 52.3 (13.1) | 52.0 (13.4) | 52.5 (13.3) | |
| Median | 53.0 | 52.0 | 52.0 | 52.0 | |
| Region, N(%) | <0.0001 | ||||
| Northeast Region | 506 (10.1%) | 152 (3.5%) | 59 (1.3%) | 717 (5.2%) | |
| North Central Region | 856 (17.1%) | 632 (14.4%) | 273 (6.1%) | 1761 (12.7%) | |
| South Region | 1947 (38.9%) | 1776 (40.5%) | 2403 (53.5%) | 6126 (44.1%) | |
| West Region | 743 (14.9%) | 497 (11.3%) | 170 (3.8%) | 1410 (10.2%) | |
| Unknown Region | 7 (0.1%) | 6 (0.1%) | 11 (0.2%) | 24 (0.2%) | |
| Medicaid | 943 (18.9%) | 1325 (30.2%) | 1573 (35.0%) | 3841 (27.7%) | |
| Insurance source, N(%) | <0.0001 | ||||
| Commercial Insurance | 3255 (65.1%) | 2580 (58.8%) | 2343 (52.2%) | 8178 (58.9%) | |
| Medicaid | 943 (18.9%) | 1325 (30.2%) | 1573 (35.0%) | 3841 (27.7%) | |
| Medicare | 804 (16.1%) | 483 (11.0%) | 573 (12.8%) | 1860 (13.4%) | |
| Year, N(%) | <0.0001 | ||||
| 2007 | 670 (13.4%) | 682 (15.5%) | 628 (14.0%) | 1980 (14.3%) | |
| 2008 | 803 (16.1%) | 762 (17.4%) | 852 (19.0%) | 2417 (17.4%) | |
| 2009 | 1006 (20.1%) | 936 (21.3%) | 1017 (22.7%) | 2959 (21.3%) | |
| 2010 | 809 (16.2%) | 658 (15.0%) | 665 (14.8%) | 2132 (15.4%) | |
| 2011 | 851 (17.0%) | 712 (16.2%) | 683 (15.2%) | 2246 (16.2%) | |
| 2012 | 863 (17.3%) | 638 (14.5%) | 644 (14.3%) | 2145 (15.5%) |