“…From the cost-effective point of view, to prevent is most favorable than to treat. Indeed, during the past decade, researchers have made substantial attempts to address the prevention, and numerous influential factors have been well established, e.g., male sex, advanced age, obesity, history of a chronic respiration disease, active smoking, undernutrition, greater comorbidity index (American Society of Anesthesiologists score ≥ III) or presence of a specific comorbidity or condition (diabetes, renal insufficiency, dementia, anemia, hypoalbuminemia, lower oxygen status), delay to surgery, surgical method (arthroplasty vs. osteosynthesis) and mechanical ventilation ( 4 , 6 , 8 , 10 – 12 ). However, some limitations should be noted, including but not limited to relatively small sample size, inadequate confounders for adjustment, and inaccuracy in data collection.…”