CRP and COVID-19: This study has some limitation, including its inherent observational nature and the potential loss of perioperative analytical data (particularly, analytical parameters related to COVID-19 infection: CRP, D-dimer, ferritin, procalcitonin, LDH, and troponin), especially during the “pre-pandemic” period and the first weeks of the “pandemic period” (the beginning of health contact with the SARS-CoV-2 virus in Spain and/or absence of specific COVID-19 protocols or analytical profiles).