Table 1.
Baseline characteristics of the unmatched and the propensity score–matched cohort
|
Variable |
Unmatched cohort |
Matched Cohort |
||||||
|---|---|---|---|---|---|---|---|---|
| Non-CRT group (n = 720) | CRT group (n = 285) | P value | % Missing | Non-CRT group (n = 192) | CRT group (n = 192) | P value | SD | |
| Follow-up time in months, median [IQR]† | 61.50 [31.75, 99.25] | 38.00 [21.00, 73.00] | <.001 | 0.0% | 47.00 [27.75, 76.75] | 43.50 [24.00, 75.50] | .469 | - |
| Male, n (%)†‡ | 489 (67.9) | 242 (84.9) | <.001 | 0.0% | 160 (83.3) | 160 (83.3) | 1 | 0.06 |
| Age at explant, mean (SD)†‡ | 63.98 (15.92) | 67.96 (10.70) | <.001 | 0.0% | 67.81 (12.92) | 67.62 (11.18) | .876 | 1.25 |
| Time to reimplant, days†‡ | 0.00 [0.00, 10.00] | 7.00 [0.00, 12.00] | .029 | 0.8% | 6.00 [0.00, 11.00] | 6.00 [0.00, 11.00] | .897 | 0.44 |
| Reimplanted on same day, n (%)†‡ | 365 (50.7) | 128 (44.9) | .113 | 0.8% | 86 (44.8) | 87 (45.3) | 1 | 0.87 |
| Reimplanted within 7 days, n (%)†‡ | 470 (65.3) | 159 (55.8) | .006 | 0.8% | 118 (61.5) | 114 (59.4) | .754 | 0.93 |
| Lead dwell time (months), median [IQR]†‡ | 70.30 [21.73, 125.78] | 56.30 [21.00, 97.00] | .009 | 2.8% | 65.95 [27.30, 121.22] | 57.40 [21.62, 107.93] | .205 | 1.11 |
| Lead dwell time (years), median [IQR]†‡ | 5.90 [1.80, 10.50] | 4.70 [1.80, 8.10] | .01 | 4.5% | 5.50 [2.27, 10.10] | 4.80 [1.80, 9.00] | .206 | 1.11 |
| CRTP, n (%) | - | 61 (21.4) | - | 0.3% | - | 53 (27.6) | - | - |
| CRTD, n (%) | - | 224 (78.6) | - | 0.3% | - | 139 (72.4) | - | - |
| No. of patients without LV lead extracted (as % of CRT devices) | - | 33 (11.6) | - | 0.0% | - | 15 (7.8) | - | - |
| ICD, n (%) | 286 (39.7) | - | - | 0.0% | 114 (59.4) | - | <0.001 | - |
| Pacing device, n (%) | 434 (60.3) | - | - | 0.0% | 78 (40.6) | 0 (0.0) | <0.001 | - |
| Local infection, n (%)†‡ | 255 (35.4) | 108 (37.9) | .506 | 0.1% | 81 (42.2) | 75 (39.1) | .603 | 0.90 |
| Systemic infection, n(%)†‡ | 114 (15.8) | 45 (15.8) | 1 | 0.0% | 25 (13.0) | 28 (14.6) | .767 | 0.70 |
| Any infection, n (%)†‡ | 369 (51.2) | 153 (53.7) | .531 | 0.0% | 106 (55.2) | 103 (53.6) | .838 | 0.97 |
| Lead dysfunction, n (%)† | 233 (32.4) | 103 (36.1) | .284 | 0.0% | 46 (24.0) | 70 (36.5) | .011 | - |
| Functional lead, n (%)† | 21 (2.9) | 3 (1.1) | .13 | 0.3% | 6 (3.1) | 3 (1.6) | .5 | - |
| Lead complication, n (%)† | 52 (7.2) | 21 (7.4) | 1 | 0.0% | 20 (10.4) | 12 (6.2) | .196 | - |
| Lead access, n (%)† | 39 (5.4) | 9 (3.2) | .177 | 0.5% | 22 (11.5) | 8 (4.2) | .013 | - |
| Lead pain, n (%)† | 12 (1.7) | 2 (0.7) | .38 | 0.3% | 2 (1.0) | 2 (1.0) | 1 | - |
| Other indication, n (%)† | 72 (10.0) | 21 (7.4) | .239 | 0.0% | 23 (12.0) | 11 (5.7) | .048 | - |
| LVEF, mean (SD)†‡ | 47.43 (12.09) | 35.48 (12.42) | <.001 | 12.3% | 38.09 (13.37) | 37.70 (12.42) | .764 | 1.07 |
| Ischemic heart disease, n (%)†‡ | 225 (31.2) | 167 (58.6) | <.001 | 2.7% | 100 (52.1) | 107 (55.7) | .539 | 0.98 |
| CABG, n (%)†‡ | 70 (9.7) | 64 (22.5) | <.001 | 2.9% | 37 (19.3) | 37 (19.3) | 1 | 0.32 |
| Valve disease, n (%)†‡ | 67 (9.3) | 31 (10.9) | .523 | 3.0% | 25 (13.0) | 23 (12.0) | .877 | 0.64 |
| Heart failure, n (%)†‡ | 152 (21.1) | 232 (81.4) | <.001 | 2.6% | 141 (73.4) | 140 (72.9) | 1 | 0.17 |
| Diabetes mellitus, n (%)†‡ | 80 (11.1) | 76 (26.7) | <.001 | 3.6% | 38 (19.8) | 42 (21.9) | .706 | 0.66 |
| Hypertension, n (%)†‡ | 248 (34.4) | 139 (48.8) | <.001 | 3.7% | 87 (45.3) | 88 (45.8) | 1 | 1.11 |
| Peripheral vascular disease, n (%)†‡ | 16 (2.2) | 22 (7.7) | <.001 | 3.6% | 11 (5.7) | 8 (4.2) | .638 | 0.29 |
| Stroke, n (%)†‡ | 45 (6.2) | 33 (11.6) | .007 | 3.4% | 17 (8.9) | 19 (9.9) | .861 | 0.59 |
| Chronic respiratory disease, n (%)†‡ | 69 (9.6) | 55 (19.3) | <.001 | 3.6% | 27 (14.1) | 29 (15.1) | .885 | 0.63 |
| Chronic kidney disease, n (%)†‡ | 98 (13.6) | 88 (30.9) | <.001 | 2.3% | 49 (25.5) | 53 (27.6) | .729 | 0.70 |
| Total number of comorbidities, n (%)†‡ | <0.001 | 0.0% | 0.549 | 0.93 | ||||
| 0 | 258 (35.8) | 10 (3.5) | 11 (5.7) | 10 (5.2) | ||||
| 1 | 152 (21.1) | 35 (12.3) | 35 (18.2) | 31 (16.1) | ||||
| 2 | 138 (19.2) | 61 (21.4) | 43 (22.4) | 49 (25.5) | ||||
| 3 | 91 (12.6) | 61 (21.4) | 43 (22.4) | 38 (19.8) | ||||
| 4 | 52 (7.2) | 55 (19.3) | 34 (17.7) | 31 (16.1) | ||||
| 5 | 16 (2.2) | 35 (12.3) | 13 (6.8) | 19 (9.9) | ||||
| 6 | 10 (1.4) | 24 (8.4) | 10 (5.2) | 14 (7.3) | ||||
| 7 | 3 (0.4) | 4 (1.4) | 3 (1.6) | 0 (0.0) | ||||
| Creatinine level (mg/dL), mean [SD]†‡ | 89.00 [75.00, 110.00] | 108.00 [86.00, 136.00] | <.001 | 1.6% | 100.00 [83.00, 127.25] | 102.00 [83.00, 129.25] | .892 | 0.90 |
| eGFR (mL/min/1.73 m2), mean (SD)†‡ | 70.45 (18.61) | 60.34 (19.90) | <.001 | 1.6% | 63.88 (20.15) | 63.11 (19.98) | .707 | 1.09 |
| eGFR <60 mL/min/1.73 m2, n (%)†‡ | 194 (26.9) | 135 (47.4) | <.001 | 1.6% | 73 (38.0) | 80 (41.7) | .532 | 0.97 |
| History of previous extraction, n (%)†‡ | 72 (10.0) | 46 (16.1) | .009 | 0.0% | 25 (13.0) | 27 (14.1) | .881 | 0.57 |
| No. of previous device interventions, n (%)†‡ | .038 | 0.1% | .506 | 0.56 | ||||
| 0 | 647 (89.9) | 239 (83.9) | 166 (86.5) | 165 (85.9) | ||||
| 1 | 44 (6.1) | 25 (8.8) | 15 (7.8) | 12 (6.2) | ||||
| 2 | 28 (3.9) | 21 (7.4) | 10 (5.2) | 15 (7.8) | ||||
| 3 or more | 1 (0.1) | 0 (0.0) | 1 (0.5) | 0 (0.0) | ||||
| Superior approach, n (%)† | 703 (97.6) | 282 (98.9) | .276 | 0.0% | 189 (98.4) | 189 (98.4) | 1 | - |
| Manual traction only, n (%)†‡ | 141 (19.6) | 53 (18.6) | .788 | 0.0% | 30 (15.6) | 36 (18.8) | .499 | 0.72 |
| Nonpowered tool only, n (%)†‡ | 121 (16.8) | 58 (20.4) | .218 | 0.0% | 35 (18.2) | 34 (17.7) | 1 | 0.76 |
| Powered tools only, n (%)†‡ | 81 (11.2) | 30 (10.5) | .827 | 0.0% | 16 (8.3) | 19 (9.9) | .723 | 0.56 |
| Inferior approach, n (%)†‡ | 68 (9.4) | 36 (12.6) | .167 | 0.3% | 23 (12.0) | 26 (13.5) | .76 | 0.74 |
| Complete removal, n (%)†‡ | 635 (88.2) | 242 (84.9) | .193 | 0.0% | 172 (89.6) | 164 (85.4) | .28 | 0.64 |
| Partial removal, n (%)†‡ | 64 (8.9) | 35 (12.3) | .131 | 0.0% | 15 (7.8) | 21 (10.9) | .381 | 0.54 |
| Clinical failure, n (%)†‡ | 6 (0.8) | 3 (1.1) | 1 | 0.0% | 1 (0.5) | 2 (1.0) | 1 | 0.15 |
| Minor complications, n (%)†‡ | 59 (8.2) | 26 (9.1) | .726 | 0.0% | 15 (7.8) | 15 (7.8) | 1 | 0.15 |
| Major complications, n (%)†‡ | 16 (2.2) | 2 (0.7) | .169 | 0.0% | 2 (1.0) | 2 (1.0) | 1 | 0.02 |
Continuous variables are presented as mean (standard deviation) or median [interquartile range] as appropriate, categorical as frequency (%). The t test was used to compare CRT subjects vs non-CRT subjects for continuous variables; the Fisher exact test was used for categorical variables. Standardized differences (SD) are defined as the difference in means, proportions, or ranks divided by the mutual standard deviation.
CABG = coronary artery bypass graft; CRTD = cardiac resynchronization therapy defibrillator; CRTP = cardiac resynchronization therapy pacemaker; eGFR = estimated glomerular filtration rate; ICD = implantable cardiac defibrillator; LV = left ventricular; LVEF = left ventricular ejection fraction.
†
Variables were included in the multiple imputation models together with the outcomes all-cause death and hospitalization.
‡
Variables were used for the calculation of propensity scores.