Table 3 summarizes the clinical characteristics of the infected and uninfected patients. The occurrence of infection was associated with age (P = 0.006), BMI (P = 0.001), WBC count (P = 0.019), CRP (P = 0.038), hydromorphone dosage (P = 0.014), and biological sex (P = 0.024). The gene discussed is CRP; the disease is infection.