Role of fecal calprotectin as a hypoxic intestinal damage biomarker in COVID-19 patients

Gut Pathog. 2022 Aug 9;14(1):34. doi: 10.1186/s13099-022-00507-y.

Abstract

Background: Gastrointestinal manifestations of coronavirus disease 2019 (COVID-19) appear to be substantial. Fecal calprotectin is a promising biomarker in COVID-19 associated gastrointestinal inflammation; however, its role in the severity of COVID-19 remains limited. We conducted a study to analyze the relationship between the severity of COVID-19 and hypoxic intestinal damage.

Methods: We assessed the severity of 44 hospitalized COVID-19 pneumonia patients based on the PaO2/FiO2 (P/F) ratio. Inflammatory markers were measured from blood samples, and fecal calprotectin was obtained from stool samples.

Results: Median levels of fecal calprotectin in COVID-19 patients involved in this study (n = 44) were found to be markedly elevated along with the severity of hypoxemia, as seen in the non-acute respiratory distress syndrome (ARDS) group 21.4 µg/g (5.2-120.9), mild ARDS 54.30 µg/g (5.2-1393.7), moderate ARDS 169.6 µg/g (43.4-640.5), and severe ARDS 451.6 µg/g (364.5-538.6). We also found significant differences in fecal calprotectin levels based on the severity of ARDS (P < 0.001), and although the patients were divided into ARDS and non-ARDS groups (P < 0.001). Furthermore, we found a strong negative correlation between the P/F ratio and fecal calprotectin levels (r = - 0.697, P < 0.001).

Conclusion: Our findings support the potential role of fecal calprotectin as a biomarker of intestinal inflammation in COVID-19 as a consequence of hypoxic intestinal damage and as suggested by the reduced P/F ratio.

Keywords: COVID-19; Fecal calprotectin; Infectious disease; P/F ratio.