Perioperative C-reactive protein is associated with pain outcomes after major laparoscopic abdominal surgery: a retrospective analysis

Purpose: This study is aimed to investigate an association between perioperative C-reactive protein (CRP) levels and both opioid consumption and postoperative pain scores in postoperative days (PODs) in patients who underwent laparoscopic major abdominal surgery. We hypothesized that postoperative opioid requirements and numeric rating scale (NRS) pain scores would be positively associated with perioperative CRP levels. Patients and method: Medical records from 4,653 patients who underwent a laparoscopic major abdominal surgery from January 2010 to December 2016 were retrospectively reviewed. Generalized linear regression analysis was used to identify the association of preoperative and postoperative CRP levels, and increase in CRP level (postoperative CRP level – preoperative CRP level) with postoperative pain outcomes during POD 0–3. Results: An increase of 1 mg dL(−1) of postoperative CRP level was significantly associated with 1.4% increase morphine equivalent consumption [exponentiated regression (Exp) coefficient: 0.014, 95% CI (0.011, 0.016), P<0.001], whereas preoperative CRP levels were not significantly associated with morphine equivalent consumption on POD 0–3 (P=0.450). A 1 mg dL(−1) of increase in CRP level was significantly associated with 1% increase of morphine equivalent consumption [Exp coefficient: 0.010, 95% CI (0.008, 0.012), P<0.001]. Postoperative CRP levels were positively associated with NRS pain scores on POD 1, POD 2, and POD 3 (P<0.001). Increases of CRP levels were also positively associated with NRS pain scores on POD 0, POD 1, POD2, and POD3 (P<0.05). Conclusion: These results suggest postoperative CRP levels and increases in CRP levels are positively associated with opioid consumption and higher pain scores after major laparoscopic abdominal surgery.