Background: fecal calprotectin is a selection tool prior to endoscopic studies in patients with gastrointestinal symptoms. However, some symptomatic patients with altered fecal calprotectin will not have any endoscopic lesions. The aim of the study was to determine the factors associated with the presence of altered fecal calprotectin in patients with negative endoscopic studies of the colon and small bowel.
Methods: this was an observational, prospective study of patients with digestive symptoms. The association of different clinical factors with elevated fecal calprotectin in the absence of endoscopic lesions of the colon and small bowel were analyzed.
Results: 143 patients were included in the study, 98 were female (68.5 %) and the mean age was 40.06 ± 16.42 (15-82) years. Smoking and non-steroidal anti-inflammatory drug intake were associated with altered fecal calprotectin in patients with a negative endoscopy of the colon and small bowel (p = 0.029 and p = 0.006). The mean values of fecal calprotectin were significantly higher in smokers, users of non-steroidal anti-inflammatory drugs and patients with small intestine bacterial overgrowth. Smoking (OR: 3.505; p = 0.028), non-steroidal anti-inflammatory drugs intake (OR: 3.473; p = 0.021) and small intestine bacterial overgrowth (OR: 3.172; p = 0.013) were independent risk factors for altered fecal calprotectin in the absence of endoscopic lesions. No association was found for any of the other variables.
Conclusions: smoking and the use of non-steroidal anti-inflammatory drugs are strongly associated with elevated levels of fecal calprotectin in symptomatic patients with a negative colonoscopy and capsule endoscopy of the small bowel. Small intestine bacterial overgrowth is also associated.