Today, we’re speaking to Dr Rob Perry, who is a Gastroenterology Clinical Research Fellow based at Imperial College London.

Title of paper: Evaluating the Role of Faecal Calprotectin in Older Adults

Available at: https://doi.org/10.3399/BJGP.2025.0169

There is considerable uncertainty surrounding the use of FC as a diagnostic test in older adults, with varying suggestions in guidelines and a lack of data in the wider literature. This study investigates the performance of FC in older adults (≥50 years), compared to a younger cohort, with a view to guide its correct use in a primary care setting. These data suggest that FC is a sensitive test for IBD and organic gastrointestinal pathology in both groups. However, concerns remain over its PPV and specificity, particularly in older adults, and it should not be used if colorectal cancer is suspected.

Transcript

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Speaker A

00:00:00 .880 - 00:00:49 .180

Hello and welcome to BJGP Interviews. I'm Nada Khan and I'm one of the Associate Editors of the bjgp. Thanks for taking the time today to listen to this podcast. Today we're speaking to Dr.

Rob Perry, who is a gastroenterology Clinical Research Fellow based at Imperial College London. We're here to talk about the paper he's recently published here in the BJGP titled Evaluating the Role of Fecal Calprotectin in Older Adults.

So thanks, Rob, for joining me here to talk about your work.

And I guess I just really want to preface this by saying that a lot has changed in the last few years just in terms of testing for inflammatory bowel disease and bowel cancer in general practice. But I wonder if you could just talk us through this, some of the different guidelines and why you wanted to do this study.

Speaker B

00:00:49 .660 - 00:02:24 .450

Oh, yes, thank you for having me.

Firstly, and the rationale for the study is that, you know, consultations for gastrointestinal symptoms make up a large number of consultations in primary care. I think the figures around 10%.

And whilst fecal cow protection is an increasingly well established test for differentiating between inflammatory bowel disease and functional or other gastrointestinal or non inflammatory gastrointestinal diseases, its role in older adults is far less well established.

With varying guidelines for clinicians in primary care, the NICE guidelines make no specific mention, for example, of age, other than that calprotectin should not be used where age is considered a risk factor in the context of certain symptoms. For suspicion of cancer, the BSG guidelines on IBD use a cutoff of 40, above which they suggest calprotectin is not used.

The something called the NICE York Fecal cow protectant care pathway suggests an age cut above 60, which is a NICE endorsed pathway. So there's some uncertainty there in the literature about which cutoff should be used for fecal cow protectin.

And the reason any cutoff is suggested is because data has previously shown that calprotectin lacks sensitivity for diagnosing colorectal cancer.

And as age is considered a risk factor for colorectal cancer, guidelines normally mandate earlier endoscopic evaluation of patients with GI symptoms in older age groups.

Speaker A

00:02:24 .530 - 00:02:39 .170

And can you just talk us through briefly what you did here? So you looked at patients referred for a colonoscopy at one single centre, so at Imperial College Healthcare Trust.

But just talk us through briefly who was included in the study and what were you looking at specifically?

Speaker B

00:02:40 .380 - 00:04:04 .090

So looking at patients where calprotectin was being used for diagnostic purposes, so calprotectin is also, as you probably know, well established for monitoring patients with existing ibd, monitoring response to treatment for flares, et cetera. We were just looking at patients where it was being used for diagnostic purposes. So any patients with existing IBD were excluded from the study.

And then, yes, as you said, anyone who had a calprotectin within a six month period back in 2021, who then subsequently within a one year period had a colonoscopy performed at Imperial, which is the local referral centre, that were included in the study. And we only looked at adult patients. We had a cohort of older adults which we used to cut 50 and above, and a younger cohort below that.

We didn't look at pediatric cases, that was how we selected patients.

And then we reviewed available electronic documentation to ascertain the diagnosis of the patient, looking at clinic betters etc, as well as looking at other tests that patients may have had performed when their symptoms are being evaluated. Fit testing, for example. We also looked at CRP and haemoglobin.

By collecting that data, we were able to ascertain the diagnostic performance of chiroprotectin in the two respective cohorts. And also in comparison with some of the other clinical tests that I mentioned.

Speaker A

00:04:04 .710 - 00:04:21 .670

Yeah.

And as you point out, because these tests might be used in quite a varied fashion depending on patient age or presentation, I suppose it's important to kind of work out what the diagnostic capabilities of them are. And I think that's what this study really aimed to achieve. Really.

Speaker B

00:04:22 .630 - 00:05:04 .510

Yes, exactly.

So we were trying to look at how calprotectin performed in the older age group compared to the younger age group, and also looking at how its performance relative to fit testing in those two cohorts. We looked at the performance of calprotectin, the differentiating between inflammatory bowel disease and non organic GI pathology.

And we also looked at its ability to differentiate between organic GI pathology more generally. So inflammatory bowel disease, colorectal cancer and other significant GI diagnoses and non organic pathology.

Those two questions, which I think are important questions when considering patients presenting with GI symptoms in primary care.

Speaker A

00:05:05 .710 - 00:05:14 .190

And just talk us through what you found here. And I think the results were really striking in terms of things were different according to age and maybe not surprisingly. But talk us through that.

Speaker B

00:05:15 .550 - 00:07:19 .810

I think the key findings are firstly that calprotectin remains a sensitive test in both groups.

So sensitivity when using a cutoff of 50 micrograms per gram, which is the nice advised cutoff for considering a positive calprotectin Test suggested by nice.

There are other, you know, there is other data in the literature about altering the cutoff which calprotectin is considered positive, but 50 is the cut, you know, is one of the cut offs we looked at and is what is suggested by, in the NICE guidelines using that cutoff, you get sensitivities of over 90% for diagnosing IBD from non organic GI pathology in both age groups. What you see in the older age group is a significantly lower positive predictive value. So positive predictive value of only about 12%.

And using that cutoff in the patients who had, again using that cutoff of 50 in the small number of patients who did have colorectal cancer, if you then did try to push up the threshold at which calprotectin is considered positive, as many guidelines do suggest, you would then start to, to miss cases of colorectal cancer, which just highlights one of the important messages of the paper and that is clearly documented in the NICE guidelines that calprotectin shouldn't be used as a biomarker for cancer and if cancer is suspected, patients should be referred on the appropriate urgently suspected cancer pathway. We also found that calprotectin did perform better than fit tests for diagnosing ibd.

But, but there's also potentially some future work to be done in patients who may have had FIT testing because of concern over potential colorectal cancer.

But in patients where FIT is negative, calprotectin may then have a role as a good rule out test in that group where you've already ruled out suspected cancer.

So that's maybe an area for future work and maybe it just helps to allow us to think about how we may have a more kind of joined up pathway for evaluating patients with lower GI symptoms in primary care.

Speaker A

00:07:20 .930 - 00:07:30 .290

And I know some local guidelines might suggest faecal calprotectin alongside FIT in younger age groups. What are your thoughts about this based on the results of this work?

Speaker B

00:07:30 .930 - 00:08:26 .550

I think it depends what symptoms the patient's presenting with.

I think if patients present with symptoms that according to the NICE guideline that's potentially suggestive of colorectal cancer, then obviously they should be evaluated, you know, appropriately with FIT testing or, you know, onward referral. And I think, you know, I think calprotectin clearly has a role in younger patients for differentiating between non organic GI disea