Suggested Flowchart Through Integrated C-Reactive Protein and White Blood Cell Count Analysis for Screening for Early Complications After Gastric Bypass: a Single-Center Retrospective Study

Introduction: Early leakage detection following bariatric procedures is crucial, but a standardized evaluation method is lacking. The aim was to validate the potential benefits of postoperative day 1 (POD1) C-reactive protein (CRP) levels and white blood cell (WBC) counts in distinguishing at-risk patients following Roux-en-Y gastric bypass (RYGB) while considering the impact of obesity-related chronic inflammation. Methods: Retrospective analysis of 261 consecutive patients aged 18–65 years with a body mass index (BMI) of 32.5–50 kg/m² who underwent primary RYGB between 2017 and 2022. Sequential changes in CRP levels and WBC counts measured 48 h preoperatively and on POD1 morning were collected and compared between patients with/without complications and in patients without complications stratified by preoperative CRP levels. Results: Female patients and those with a higher BMI tended to have higher baseline CRP levels, which were positively related to postoperative CRP. Patients experiencing complications had higher WBC counts and a higher prevalence of WBC counts >14,000/μl (77.8% vs. 25.4%; p<0.001) than those without complications. Baseline CRP ≥ 0.3 mg/dl, a longer operative time, and blood loss >10 ml were significantly more common with WBC counts above 14,000/μl; a reasonable range of change in WBC count (∆WBC) derived from its positive correlation to postoperative WBC count (r=0.6695) may serve as a useful complementary indicator. Conclusion: An individualized CRP threshold setting and integrated interpretation of the WBC count can be more appropriate than using static criteria for differentiating at-risk patients after RYGB. Further studies are needed to validate these findings and determine their generalizability. Graphical abstract: [Figure not available: see fulltext.]