Correlation between serum amyloid A levels and gallbladder pathologies: A retrospective clinical study

Abstract

Aim: To evaluate the diagnostic utility of Serum Amyloid A (SAA) levels and independently assessed its association with cholelithiasis, biliary sludge, and a history of cholecystectomy.

Methods: Data from 290 symptomatic adult patients presenting with chronic abdominal or back pain were retrospectively analyzed. Patients with active infections, malignancies, or autoimmune disorders were excluded. Patients were stratified into Low SAA (<1 mg/dL) and High SAA (≥1 mg/dL) groups. Diagnostic threshold performance was validated using Receiver Operating Characteristic (ROC) curve analysis. Multivariable logistic regression, adjusted for age and sex, estimated independent Odds Ratios (OR) and 95% Confidence Intervals (CI).

Results: The cohort comprised 193 females and 97 males (mean age: 51.60 ± 18.95 years). ROC analysis demonstrated that the 1 mg/dL threshold predicted gallbladder pathology accurately (AUC = 0.784; 95% CI: 0.723–0.845; p < 0.001), with 69.8% sensitivity and 75.1% specificity. Multivariable regression revealed that elevated SAA (≥1 mg/dL) was a powerful independent predictor for cholelithiasis (Adjusted OR = 5.98; 95% CI: 2.84–12.56; p < 0.001), biliary sludge (Adjusted OR = 3.84; 95% CI: 1.62–9.10; p = 0.002), and historical cholecystectomy (Adjusted OR = 2.65; 95% CI: 1.26–5.58; p = 0.011). Notably, 54.54% of radiographically normal controls also exhibited elevated SAA (p < 0.001).

Conclusion: Elevated SAA levels are significantly and independently associated with specific gallbladder pathologies, particularly cholelithiasis and biliary sludge. While SAA robustly reflects subclinical systemic inflammatory burden, its high prevalence in normal controls confirms it represents a non-specific systemic biomarker rather than an organ-specific indicator.