Proton pump inhibitor use is associated with elevated faecal calprotectin levels. A cross-sectional study on subjects referred for colonoscopy

Figures & data

Figure 1. Flow diagram showing how the study population were selected.

Table 1. Basal characteristics, cause of referral for colonoscopy and faecal calprotectin outcome in patients (n = 590) referred for colonoscopy with a normal colonoscopy outcome. Note that a single patient may have more than one cause of referral.

Mean age years (SD)	61.7 (14.4)
Proportion of:
Men	46 % (n=271)
Women	54 % (n=319)
The cause of referral for colonoscopy
Anaemia	13 % (n=75)
Rectal bleeding	22 % (n=109)
Diarrhoea	17 % (n=101)
Occult bleeding	31 % (n=185)
Weight loss	5 % (n=30)
Change in bowel habits	14 % (n=82)
Abdominal pain/irritable bowel syndrome	17 % (n=102)
Median faecal calprotectin in ug/g (25th–75th percentile)	31 (20–85)
The proportion of subjects with a faecal calprotectin >50 μg/g	36 % (n=212)

Table 2. Patients referred for colonoscopy and with a normal colonoscopy finding (n = 590). Logistic regression with dependent variable FC >50 µg/g and independent variables age, male gender, diverticulosis and drugs.

Variable	Univariate (expB) odds ratio (95th % confidence interval)	Multivariate (expB) odds ratio (95th % confidence interval)
Age	1.058 (1.042–1.075)	1.051 (1.032–1.071)^a
Male gender	1.164 (0.831–1.631)	1.330 (0.882–2.006)
Diverticulosis	1.476 (1.046–2.081)	0.839 (0.552–1.275)
Acetylsalicylic acid	3.598 (2.365–5.476)	2.934 (1.085–3.448)^a
Dipyridamole	3.272 (0.947–11.313)	1.329 (0.329–5.367)
Non-steroidal anti-inflammatory drugs	2.543 (1.399–4.623)	2.411 (1.162–5.002)^a
Paracetamol	1.608 (1.031–2.506)	1.105 (0.628–1.946)
Proton pump inhibitors	4.091 (2.704–6.189)	3.843 (2.338–6.316)^a
Drugs for obstipation	2.326 (1.122–4.821)	1.123 (0.433–2.913)
Drugs for irritable bowel syndrome	2.705 (1.387–5.276)	1.990 (0.893–4.435)
Prednisolone	2.320 (1.119–4.808)	1.412 (0.587–3.396)
Per oral iron supplements	3.668 (1.605–8.385)	2.209 (0.788–6.195)
B-vitamins	1.900 (1.175–3.073)	1.091 (0.583–2.043)
Nitroglycerin	5.407 (2.463–11.870)	1.995 (0.785–5.068)
Beta–blockers	2.074 (1.383–3.110)	1.037 (0.604–1.780)
Calcium channel inhibitors	1.893 (1.224–2.926)	1.142 (0.672–1.939)
Angiotensin-converting-enzyme inhibitors	1.789 (1.106–2.894)	1.204 (0.683–2.122)
Diuretics	1.918 (1.268–2.9011)	1.116 (0.657–1.895)
Statins	2.305 (1.534–3.462)	1.217 (0.684–2.165)
Inhalation steroids	2.114 (1.234–3.619)	1.924 (0.742–4.986)
Inhalation beta 2 receptor agonists	1.862 (1.056–3.285)	1.086 (0.394–2.992)
Gabapentin	3.779 (1.112–12.569)	2.776 (0.728–10.582)
The use of four or more drugs	3.110 (2.187–4.423)	0.710 (0.400–1.260)

^a Statistically significant multivariable odds ratios.

Table 3. The outcome of faecal calprotectin (FC) test and a faecal immunological test (FIT) in patients referred for colonoscopy and with a normal colonoscopy finding (n = 277). A FC above 50 µg/g is regarded as a positive FC test. The proportion of positive tests is shown for all patients and for patients using acetylsalicylic acid, non-steroidal anti-inflammatory drugs and proton pump inhibitors.

	All patients (n = 277)	Acetylsalicylic acid (n = 47)	Non-steroidal anti-inflammatory drugs (n = 21)	Proton pump inhibitors (n = 58)
Both FC and FIT negative	63% (n=174)	28% (n=13)	58% (n=12)	24% (n=17)
Only FIT positive	5% (n=14)	8% (n=4)	5% (n=1)	7% (n=4)
Only FC positive	27% (n=75)	55% (n=26)	24% (n=5)	52% (n=30)
Both FC and FIT positive	5% (n=14)	8% (n=4)	14% (n=3)	12% (n=7)

Table 4. The correlation between reported gastrointestinal symptoms and faecal calprotectin in patients referred for colonoscopy and with a normal colonoscopy outcome.

GSRS Subscore	rs	p-value
Abdominal pain	0.068	.102
Bloating	0.072	.068
Constipation	0.062	.141
Diarrhoea	0.091	.029^a
Early Satiety	0.099	.017^a
Gastroesophageal reflux	–0.007	.873
Dyspepsia	0.093	.026^a
Total GSRS-Irritable Bowel Syndrome score	0.109	.01^a

Statistics: Spearman test; GSRS: Gastrointestinal Symptom Rating Scale.

^a Statistically significant.