Table 1. Baseline characteristics in 1,601 patients who underwent open thoracotomy or minimally invasive VATS lobectomy for lung cancer in Sweden between 2012–2015 before and after inverse probability of treatment weighting.
| Variable | Unweighted | IPTW | |||||
|---|---|---|---|---|---|---|---|
| Open | VATS | SMD | Open* | VATS* | SMD | ||
| n | 1,316 | 285 | – | 1,571.1 | 1,157.4 | – | |
| Age, years, mean (SD) | 67.7 (8.6) | 67.7 (8.3) | 0.001 | 67.7 (8.6) | 67.7 (8.0) | 0.004 | |
| Female | 716 [54] | 185 [65] | 0.215 | 876.0 [56] | 655.5 [57] | 0.018 | |
| BMI, kg/m2, mean (SD) | 26.4 (4.7) | 25.4 (4.4) | 0.222 | 26.2 (4.7) | 26.0 (4.3) | 0.052 | |
| No comorbidity | 626 [48] | 118 [41] | 0.124 | 734.0 [47] | 529.5 [46] | 0.019 | |
| Heart disease | 197 [15] | 46 [16] | 0.032 | 233.6 [15] | 185.6 [16] | 0.032 | |
| Diabetes | 123 [9.3] | 22 [7.7] | 0.058 | 141.9 [9.0] | 94.1 [8.1] | 0.032 | |
| Prior stroke/TIA | 69 [5.2] | 10 [3.5] | 0.085 | 79.6 [5.1] | 51.4 [4.4] | 0.029 | |
| Chronic kidney disease | 39 [3.0] | 3 [1.1] | 0.137 | 42.6 [2.7] | 16.4 [1.4] | 0.091 | |
| Other comorbidity | 526 [40] | 141 [50] | 0.192 | 646.9 [41] | 505.9 [44] | 0.051 | |
| Performance status >0 | 482 [37] | 75 [26] | 0.223 | 553.8 [35] | 370.6 [32] | 0.068 | |
| Preoperative FEV1, liter, mean (SD) | 2.3 (0.67) | 2.2 (0.66) | 0.130 | 2.3 (0.67) | 2.3 (0.65) | 0.011 | |
| Prior thoracic surgery | 47 [3.6] | 12 [4.2] | 0.033 | 57.8 [3.7] | 31.2 [2.7] | 0.056 | |
| Prior sternotomy | 25 [1.9] | 11 [3.9] | 0.117 | 32.2 [2.0] | 26.4 [2.3] | 0.016 | |
| Current smoker | 367 [28] | 98 [34] | 0.141 | 453.1 [29] | 362.0 [31] | 0.053 | |
| Preoperative radiotherapy | 34 [2.6] | 1 [0.4] | 0.186 | 36.0 [2.3] | 13.2 [1.1] | 0.089 | |
| Preoperative chemotherapy | 46 [3.5] | 3 [1.1] | 0.164 | 49.8 [3.2] | 20.0 [1.7] | 0.094 | |
| Stage** | 0.246 | 0.066 | |||||
| IA | 543 [41] | 115 [40] | 649.1 [41] | 497.8 [43] | |||
| IB | 291 [22] | 89 [31] | 365.7 [23] | 285.5 [25] | |||
| IIA | 207 [16] | 39 [14] | 241.8 [15] | 161.1 [14] | |||
| IIB | 119 [9.0] | 15 [5.3] | 134.3 [8.5] | 91.5 [7.9] | |||
| IIIA–X | 156 [12] | 27 [9.5] | 180.2 [11] | 121.5 [10] | |||
Numbers are n [%] unless otherwise noted. *, the overall numbers of patients in each group are not integers owing to inverse probability of treatment weighting; **, pathologic stage. FEV1, forced expiratory volume in one second; IPTW, inverse probability of treatment weighting; SD, standard deviation; SMD, standardized mean difference; TIA, transient ischemic attack; VATS, video-assisted thoracoscopic surgery.