Faecal Calprotectin may help distinguish IBD from IBS in primary care setting

Fecal calprotectin (FC) is a reliable marker of intestinal inflammation. It differentiates between inflammatory bowel disease (IBD) and irritable bowel syndrome (IBS). This tool is also valuable for monitoring disease activity in IBD patients.

A recent study published in the Journal of Gastroenterology and Hepatology Foundation has concluded that fecal calprotectin (FC ) reliably rules out IBD and contradicts the presence of other organic gastrointestinal disease (OGID) in primary care patients. Positive FC test and other predictors, such as diarrhoea, rectal bleeding, short duration, or age >35 years, should encourage a prioritized investigation. Using nonsteroidal anti-inflammatory drugs (NSAID), proton pump inhibitors (PPI), and acetylsalicylic acid (ASA) may affect the diagnostic accuracy of FC for IBD and OGID, the team mentioned.

A retrospective analysis of data on all semiquantitative FC tests from individuals ≥18 years was conducted in primary care in Östergötland County in 2010. This study investigated the diagnostic accuracy of FC for inflammatory bowel disease (IBD) and OGID in primary care. They examined the association with demographic factors, symptoms and concomitant medical therapy.

Key findings from the study are:

• The study had 1293 eligible patients.
• IBD was found in 8.8% and other OGID in 30.8% of patients with positive FC.
• Positive FC was associated with diarrhoea, age >60 years, duration <3 Months, use of NSAID and PPI.
• Predictors of IBD were positive FC, diarrhoea, rectal bleeding, and male sex; predictors of OGID positive FC, age >35 years, abnormal clinical findings, and duration <3 Months.
• FC yielded the highest sensitivity and negative predictive value compared to demographics, symptoms, and duration.
• The use of NSAID and PPI showed a marginal increase in the sensitivity, positive predictive value, and decrease in the specificity of FC.
• Within five years, 4.0% had a new gastrointestinal diagnosis among patients with positive FC.

The use of NSAID and PPI was significantly associated with positive FC in our study; they said PPI showed the strongest association.

The study's strength includes a large, unselected, heterogeneous primary care population, FC testing concerning symptom presentation, and longer follow-up.

Combining FC with other significant predictors of IBD and OGID increases the specificity and PPV but tends to decrease the sensitivity. Although the likelihood seems to be low, the use of NSAID, PPI, and ASA may affect the diagnostic accuracy of FC for IBD and OGID, they said.

Reference:

Rendek, Z., Falk, M., Grodzinsky, E., Kechagias, S., & Hjortswang, H. (2023). Diagnostic value of faecal calprotectin in primary care patients with gastrointestinal symptoms: A retrospective Swedish cohort study. JGH Open, 7(10), 708–716. https://doi.org/10.1002/jgh3.12972