Fecal Calprotectin Levels in Post-Metabolic Bariatric Surgery Patients: A Retrospective Study

Area of Science:

• Gastroenterology
• Clinical Biomarkers
• Surgical Outcomes

Background:

• Fecal calprotectin (FCP) is a crucial biomarker for detecting gastrointestinal inflammation and differentiating irritable bowel syndrome from inflammatory bowel disease (IBD).
• Metabolic bariatric surgeries (MBSs) significantly alter gastrointestinal physiology, potentially impacting the interpretation of standard FCP cutoff values.
• The applicability of established FCP thresholds in patients who have undergone MBS requires investigation to ensure accurate diagnostic utility.

Purpose of the Study:

• To determine optimal FCP cutoff values for identifying relevant colonoscopy findings in patients post-MBS.
• To evaluate FCP levels and colonoscopy results in a cohort of patients following MBS.
• To perform subgroup analyses based on demographic and surgical factors to understand FCP variability.

Main Methods:

• Retrospective analysis of 340 patients who underwent MBS and subsequent FCP testing (2000-2024).
• Exclusion of patients with preoperative IBD.
• Receiver Operating Characteristic (ROC) curve analysis to identify optimal FCP cutoff values based on colonoscopy findings.

Main Results:

• The median FCP level across all patients was 51 µg/g; for those with colonoscopies (n=124), it was 61 µg/g.
• No significant difference in FCP levels was found between patients with or without relevant findings (IBD, malignancy) (p=0.101).
• ROC analysis suggested an optimal FCP cutoff of 59.5 µg/g (AUC: 0.653), but with low sensitivity (64.6%) and specificity (63.4%).

Conclusions:

• The optimal FCP cutoff value in post-MBS patients is suggested to be 59.5 µg/g.
• Given the low Youden's index and minimal difference from the standard 50 µg/g cutoff, maintaining the standard value is deemed more practical clinically.
• Further research may be needed to refine FCP interpretation in the unique physiological context following MBS.