Current smoking (RR 0.89, 95% CI 0.75-1.06; <i>P</i>=0.178), American Society of Anesthesiologists grade >2 (RR 2.63, 95% CI 0.84-8.27; <i>P</i>=0.098), increased age (WMD 1.43 years, 95% CI -1.15 to 4.02; <i>P</i>=0.278), COPD (RR 1.21, 95% CI 0.68-2.17; <i>P</i>=0.521), cardiovascular disease (RR 1.63, 95% CI 0.40-6.70; <i>P</i>=0.495), rheumatoid arthritis (RR 1.76, 95% CI 0.53-5.90; <i>P</i>=0.359), and osteoporosis (RR 1.91, 95% CI 0.79-4.63; <i>P</i>=0.152) were not risk factors for postoperative SSI.
Given that neutrophils are key effector cells in the pathogenesis of COPD, these same cells, by expressing RANKL, may be involved in osteoporosis of COPD.