Cox proportional hazard regression analysis to predict chronic postsurgical pain during the first 36 months after thoracic surgery
| HR (95% CI) | P value* | |
| Age | 1.01 (1.00 to 1.02) | 0.23 |
| Sex | ||
| Male | Reference | |
| Female | 1.20 (1.00 to 1.43) | 0.04 |
| Preoperative analgesic use | 1.00 (0.66 to 1.51) | 0.99 |
| Operative technique | ||
| VATS | Reference | |
| Thoracotomy | 1.02 (0.82 to 1.28) | 0.84 |
| Operation time, hours | 1.11 (1.03 to 1.20) | <0.01 |
| NRS score at first outpatient visit after surgery | 1.29 (1.25 to 1.34) | <0.001 |
| Postoperative chemotherapy | 1.55 (1.26 to 1.90) | <0.001 |
| Postoperative radiation therapy | 1.35 (1.05 to 1.74) | 0.02 |
| Year of surgery | ||
| 2007 | Reference | |
| 2008 | 0.77 (0.49 to 1.22) | 0.27 |
| 2009 | 0.65 (0.39 to 1.07) | 0.09 |
| 2010 | 1.05 (0.67 to 1.63) | 0.84 |
| 2011 | 1.29 (0.87 to 1.90) | 0.20 |
| 2012 | 0.92 (0.62 to 1.39) | 0.70 |
| 2013 | 0.98 (0.66 to 1.46) | 0.92 |
| 2014 | 0.88 (0.59 to 1.30) | 0.51 |
| 2015 | 0.94 (0.63 to 1.39) | 0.76 |
| 2016 | 1.14 (0.76 to 1.71) | 0.52 |
*Tested by Cox proportional hazards regression.
NRS, Numeric Rating Scale; VATS, video-assisted thoracic surgery.