Is there an added value of faecal calprotectin and haemoglobin in the diagnostic work-up for primary care patients suspected of significant colorectal disease? A cross-sectional diagnostic study

Table 4 Risk of SCD in relation to routine diagnostic predictors and faecal biomarkers as based on the optimism-corrected combined POC and the POC FIT extended diagnostic models, developed in 810 Dutch primary care patients with lower abdominal complaints referred for endoscopy in the CEDAR study^a,b

	Calprotectin POC and POC FIT extended model			POC FIT extended model
Diagnostic predictor	Regression coefficient (SE)	OR (95 % CI)	Wald P value	Regression coefficient (SE)	OR (95 % CI)	Wald P value
Patient history
Age, per 5 years	0.11 (0.05)	1.1 (1.0–1.2)	0.024	0.12 (0.05)	1.1 (1.0–1.2)	0.008
Abdominal pain	–0.20 (0.27)	0.8 (0.5–1.4)	0.45	–0.22 (0.27)	0.8 (0.5–1.3)	0.4
Rectal blood loss	0.75 (0.25)	2.1 (1.3–3.4)	0.003	0.82 (0.25)	2.3 (1.4–3.7)	<0.001
Rectal mucus	0.37 (0.24)	1.4 (0.9–2.3)	0.13	0.43 (0.24)	1.5 (1.0–2.4)	0.072
Weight loss	0.27 (0.27)	1.3 (0.8–2.2)	0.33	0.34 (0.27)	1.4 (0.8–2.4)	0.21
Change in bowel habit	0.16 (0.28)	1.2 (0.7–2.0)	0.56	0.21 (0.28)	1.2 (0.7–2.1)	0.46
Abdominal bloating	–0.49 (0.24)	0.6 (0.4–1.0)	0.043	–0.49 (0.24)	0.6 (0.4–1.0)	0.044
Constipation	–0.23 (0.24)	0.8 (0.5–1.3)	0.33	–0.19 (0.24)	0.8 (0.5–1.3)	0.43
Physical examination
Abnormal digital rectal examination	0.43 (0.49)	1.5 (0.6–4.0)	0.39	0.47 (0.47)	1.6 (0.6–4.0)	0.33
Faecal tests
Calprotectin POC test, per 100 μg/g	0.28 (0.11)	1.3 (1.1–1.7)	0.014	–	–	–
Positive POC FIT (>6 μg Hb/g^c)	1.75 (0.25)	5.8 (3.5–9.3)	<0.001	1.91 (0.24)	6.7 (4.2–10.7)	<0.001
Intercept	–4.08 (0.72)			–4.16 (0.72)
AUC (95 % CI)	0.818 (0.779–0.857)			0.813 (0.772–0.853)
Nagelkerke’s R², % (95 % CI)	30.6 (22.4–39.0)			29.5 (21.2–37.9)

AUC area under the receiver operating characteristic curve; CEDAR Cost-Effectiveness of a Decision rule for Abdominal complaints in primary caRe; CI confidence interval; FIT faecal immunochemical test for haemoglobin; OR odds ratio; POC point-of-care; SCD significant colorectal disease; SE standard error
^aAll regression coefficients, odds ratios, AUCs, and Nagelkerke’s R²s are optimism-corrected by 500-fold bootstrap resampling. Confidence intervals and Wald tests are based on optimism-corrected parameter estimates and assuming the same SE applies as before optimism-correction
^bThese models can be used to calculate the probability for a certain patient of having SCD. For example, according to the POC FIT extended model, a 60-year-old male patient with weight loss and a positive POC FIT has a 1/(1 + exp(–1 × (–4.16 + (0.12 × 60/5) – (0.22 × 0) + (0.82 × 0) + (0.43 × 0) + (0.34 × 1) + (0.21 × 0) – (0.49 × 0) – (0.19 × 0) + (0.47 × 0) + (1.91 × 1)))) = 38.5 % probability of having SCD. Similarly, according to the same model, a 60-year-old female patient with abdominal pain and bloating has a 3.1 % probability of having SCD
^cLower detection limit as stated by manufacturer

ISSN: 1741-7015