Table 2:

Unadjusted, partially adjusted and fully adjusted associations of COPD with 1-year survival and costs after inpatient elective surgery*

AnalysisAll-cause deathTotal costs
Unadjusted
HR (95% CI)
Partially adjusted
HR (95% CI)
Fully adjusted
HR (95% CI)
Unadjusted relative difference
% (95% CI)
Partially adjusted relative difference
% (95% CI)
Fully adjusted relative difference
% (95% CI)
Primary analysis2.45 (2.41–2.50)1.61 (1.58–1.64)1.26 (1.24–1.29)38.7 (38.2–39.3)13.1 (12.7–13.4)4.6 (4.3–5.0)
Sensitivity analyses
Specific definition of COPD3.53 (3.46–3.61)2.02 (1.98–2.07)1.40 (1.37–1.43)64.1 (63.2–65.1)25.6 (25.0–26.2)9.8 (9.3–10.3)
3-level definition of COPD§
 Incident COPD2.31 (2.25–2.38)1.72 (1.67–1.77)1.29 (1.26–1.33)33.4 (32.6–34.3)14.7 (14.1–15.3)5.6 (5.1–6.1)
 Prevalent COPD2.52 (2.47–2.57)1.57 (1.54–1.60)1.25 (1.22–1.28)41.4 (40.8–42.1)12.2 (11.8–12.7)4.1 (3.7–4.5)
30-day follow-up2.82 (2.73–2.91)1.72 (1.66–1.78)1.32 (1.28–1.37)26.7 (26.3–27.1)7.0 (6.7–7.3)2.1 (1.8–2.3)
Contemporary period (2014–2019)2.41 (2.34–2.49)1.63 (1.58–1.68)1.27 (1.23–1.32)36.1 (35.2–37.0)13.7 (13.1–14.3)4.9 (4.3–5.4)
  • Note: CI = confidence interval, COPD = chronic obstructive pulmonary disorder.

  • * 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 and surgical procedure. Fully adjusted models also adjust for long-term care residence, inpatient hospital admission in the year before surgery, comorbid disease (coronary artery disease, atrial fibrillation, peripheral vascular disease, hypertension, diabetes, stroke or transient ischemic attack, chronic kidney disease, cancer, lung cancer, liver disease), frailty and adjusted clinical group (ACG) categories per the Johns Hopkins ACG system.

  • Primary analysis used an exposure of physician-diagnosed COPD, defined as 1 or more ambulatory claims or 1 or more hospital admissions for COPD any time before the index surgery date.

  • The specific definition defined COPD as 3 or more ambulatory claims for COPD within any 2-year period or 1 or more COPD hospital admissions.

  • § The 3-level definition categorized patients as not having COPD, having had incident COPD within 5 years of diagnosis and prevalent COPD of greater than 5 years.