Patient demographic and clinical characteristics
| Characteristic | Ischaemic VT (n=488) | Non-ischaemic VT (n=4754) |
| Age, mean (SD) | 55.8 (7.6) | 48.7 (11.3) |
| Age categories, years, n (%) | ||
| 18–49 | 87 (17.8) | 2177 (45.8) |
| 50–64 | 401 (82.2) | 2577 (54.2) |
| Sex, n (%) | ||
| Male | 397 (81.3) | 2396 (50.4) |
| Female | 91 (18.7) | 2358 (49.6) |
| Region, n (%) | ||
| Northeast | 85 (17.4) | 835 (17.6) |
| North central | 146 (29.9) | 1194 (25.1) |
| South | 163 (33.4) | 1837 (38.7) |
| West | 85 (17.4) | 796 (17.7) |
| Unknown | 9 (1.8) | 92 (1.9) |
| Metropolitan statistical area (MSA), n (%) | ||
| Missing or not part of MSA | 94 (19.3) | 795 (16.7) |
| Part of MSA | 394 (80.7) | 3959 (83.3) |
| Insurance plan, n (%) | ||
| Comprehensive, EPO, HMO | 82 (16.8) | 768 (16.1) |
| POS, POS with Capitation, PPO | 338 (69.3) | 3408 (71.7) |
| CDHP, HDHP | 30 (6.1) | 342 (7.2) |
| Missing | 38 (7.8) | 236 (5.0) |
| Place of service, n (%) | ||
| Inpatient | 209 (42.8) | 1600 (33.6) |
| Outpatient | 279 (57.2) | 3154 (66.4) |
| ICD/CRT-D use, n (%) | 307 (62.9) | 821 (17.2) |
| Index year, n (%) | ||
| 2006 | 15 (3.1) | 283 (5.9) |
| 2007 | 27 (5.5) | 325 (6.8) |
| 2008 | 30 (6.2) | 343 (7.2) |
| 2009 | 50 (10.3) | 429 (9.1) |
| 2010 | 37 (7.6) | 486 (10.2) |
| 2011 | 77 (15.8) | 610 (12.9) |
| 2012 | 64 (13.1) | 757 (15.9) |
| 2013 | 68 (13.9) | 594 (12.5) |
| 2014 | 70 (14.3) | 581 (12.3) |
| 2015 | 50 (10.3) | 346 (7.3) |
| Charlson comorbidity index, n (%) | ||
| 0 | 0 | 2573 (54.2) |
| 1–2 | 233 (47.8) | 1795 (37.7) |
| ≥3 | 255 (52.3) | 386 (8.1) |
| CHA2DS2-VASc score, n (%) | ||
| 0 | 0 | 837 (17.6) |
| 1–2 | 190 (38.9) | 3073 (64.6) |
| ≥3 | 298 (61.1) | 844 (17.8) |
| Non-VT arrhythmia, n (%) | 461 (94.5) | 4563 (96.0) |
| Renal disease, n (%) | 91 (18.7) | 170 (3.6) |
| Valvular heart disease, n (%) | 170 (34.8) | 998 (21.0) |
| Acute ischaemic stroke, n (%) | 37 (7.6) | 127 (2.7) |
| Cardiomyopathy, n (%) | 244 (50.0) | 1063 (22.3) |
| Heart failure, n (%) | 259 (53.1) | 738 (15.5) |
| Prior hospitalisation, n (%) | ||
| 0 | 145 (29.7) | 3470 (73.0) |
| 1 | 188 (38.5) | 1016 (21.3) |
| ≥2 | 155 (31.8) | 268 (5.7) |
| Number of different antiarrhythmic drugs, n (%) | ||
| 0 | 152 (31.2) | 2098 (44.2) |
| 1 | 104 (21.3) | 1457 (30.7) |
| ≥2 | 232 (47.5) | 1199 (25.1) |
| Number of different anticoagulants, n (%) | ||
| 1 | 414 (84.8) | 4472 (94.1) |
| ≥2 | 74 (15.2) | 282 (5.9) |
| Number of different diuretics, n (%) | ||
| 0 | 319 (65.4) | 4045 (85.1) |
| 1 | 107 (21.9) | 537 (11.3) |
| ≥2 | 62 (12.7) | 172 (3.6) |
All covariates and medication use were measured in the 6-month pre-index period.
CDHP, consumer-driven health plans; EPO, Exclusive Provider Organization; HDHP, high deductible health plan; HMO, Health Maintenance Organization; POS, Point of Service; PPO, Preferred Provider Organization.