Association of Helicobacter pylori Status with Fecal Calprotectin and Fecal Occult Blood among Primary Healthcare Attendees in Baghdad, Iraq: A Cross-Sectional Study

Abstract

Background: Fecal calprotectin is a marker of gastrointestinal inflammation due to neutrophils; however, there is a lack of evidence about its correlation with H. pylori infection, especially among symptomatic individuals seeking care from primary health centers. Aim: The aim of the study was to compare the levels of fecal calprotectin and the fecal occult blood test among patients with positive and negative H. pylori infection and to assess the association of increased calprotectin level with H. pylori infection. 
Materials and Methods: In a cross-sectional study that took place in Baghdad from May 2025 to May 2026, patients with gastrointestinal symptoms were recruited. Active H. pylori infection was diagnosed using stool antigen test and ¹³C-urea breath test. Fecal calprotectin was determined as a continuous variable and also at the cut-offs of 50 and 250 µg/g. 
Results: Results: Out of 268 patients, 133 were H. pylori positive, and 135 were H. pylori negative. The median concentration of fecal calprotectin was significantly higher in H. pylori-positive subjects than in the negative ones (63.0 vs 17.0 µg/g; P<0.001). There was a rank biserial correlation between these variables equal to 0.409. The concentration exceeded 50 µg/g in 53.4% and 14.1% of subjects, respectively. After correction for age, sex, alcohol abuse, smoking, obesity, medication, diabetes mellitus, inflammatory bowel disease, diverticulitis, colon cancer, irritable bowel syndrome, peptic ulcer disease, celiac disease, lactose malabsorption, and Helicobacter species, elevated calprotectin concentration was significantly associated with H. pylori positivity (odds ratio 6.89, 95% confidence interval 3.77-12.60; P<0.001). Occult fecal positivity was also more common among H. pylori-positive patients, but adjusted odds ratio did not reach statistical significance. The area under the curve was 0.705. 
Conclusion: Positive H. pylori status correlated with increased levels of fecal calprotectin. Nevertheless, the relatively low discrimination capacity and sensitivity demonstrated by this marker make it unsuitable to be used alone for diagnosis. Further longitudinal research is necessary to assess biomarker alterations following treatment while considering the presence of comorbid conditions.