Assessment of effect modification by frailty, cancer and surgical procedure on the association between COPD and outcomes*
| Interaction | All-cause death | Total costs | ||
|---|---|---|---|---|
| Partially adjusted, COPD v. no COPD HR (95% CI) | Fully adjusted, COPD v. no COPD HR (95% CI) | Partially adjusted relative difference, COPD v. no COPD % (95% CI) | Fully adjusted relative difference, COPD v. no COPD % (95% CI) | |
| COPD by frailty | ||||
| No frailty | 1.73 (1.67 to 1.79) | 1.41 (1.38 to 1.45) | 9.2 (8.7 to 9.7) | 5.6 (5.3 to 6.0) |
| Frailty | 1.38 (1.33 to 1.43) | 1.09 (1.06 to 1.12) | 1.2 (0.2 to 2.2) | −2.4 (−1.5 to −3.3) |
| COPD by cancer | ||||
| No cancer | 1.75 (1.71 to 1.78) | 1.39 (1.36 to 1.42) | 14.3 (13.9 to 14.7) | 6.4 (6.1 to 6.8) |
| Cancer | 1.29 (1.25 to 1.34) | 0.97 (0.94 to 1.01) | 3.5 (2.6 to 4.5) | −6.3 (−5.5 to −7.1) |
| COPD by procedure | ||||
| Orthopedic | 1.89 (1.83 to 1.94) | 1.46 (1.41 to 1.50) | 13.7 (13.2 to 14.3) | 5.1 (4.6 to 5.6) |
| Open aortic | 1.34 (1.22 to 1.48) | 1.12 (1.02 to 1.23) | 8.4 (6.2 to 10.7) | 2.1 (0.1 to 4.1) |
| Upper abdominal MIS | 1.53 (1.41 to 1.66) | 1.22 (1.12 to 1.32) | 10.0 (8.5 to 11.6) | 1.8 (0.4 to 3.2) |
| Upper abdominal open | 1.39 (1.35 to 1.44) | 1.08 (1.05 to 1.12) | 6.5 (5.6 to 7.3) | −2.4 (−1.6 to −3.2) |
| Lower abdominal MIS | 1.91 (1.80 to 2.02) | 1.44 (1.36 to 1.52) | 19.3 (18.1 to 20.6) | 9.2 (8.1 to 10.2) |
| Lower abdominal open | 1.68 (1.51 to 1.87) | 1.49 (1.34 to 1.66) | 19.1 (17.7 to 20.5) | 13.5 (12.2 to 14.8) |
| Other vascular | 1.42 (1.34 to 1.50) | 1.16 (1.10 to 1.23) | 11.2 (9.8 to 12.5) | 3.4 (2.2 to 4.6) |
Note: CI = confidence interval, COPD = chronic obstructive pulmonary disorder, MIS = minimally invasive surgery.
↵* Partial adjustment for age (expressed as a 4-knot restricted cubic spline), sex, neighbourhood income quintile (expressed as a 5-level categorical variable), rural residence, surgical procedure. Fully adjusted models additionally adjust for long-term care residence, inpatient hospitalization in the year before surgery, comorbid disease (coronary artery disease, atrial fibrillation, peripheral vascular disease, hypertension, diabetes, stroke or TIA, chronic kidney disease, cancer, lung cancer, liver disease), frailty and adjusted clinical group (ACG) categories per the Johns Hopkins ACG system.