Combined evaluation of biomarkers as predictor of maintained remission in Crohn’s disease

Table 1 Baseline characteristics of the 40 patients with Crohn’s disease included in this study

	n = 40 patients
Age at the time of inclusion, mean ± SD (yr)	34 .0 ± 13.6
Disease duration, median (IQR) (yr)	4 (0.8-11.3)
Female gender, n (%)	21 (52.5)
Current smokers, n (%)	15 (37.5)
Prior bowel resection, n (%)	7 (17.5)
Montreal classification
Location
L1, n (%)	18 (45.0)
L2, n (%)	3 (7.5)
L3, n (%)	19 (47.5)
Behaviour
B1, n (%)	13 (32.5)
B2, n (%)	16 (40.0)
B3, n (%)	11 (27.5)
Perianal lesions, n (%)	7 (17.5)
Anti-TNF-naïve patients, n (%)	24 (60.0)
Type of anti-TNF
Infliximab, n (%)	16 (40.0)
Adalimumab, n (%)	24 (60.0)
Concomitant medications
Immunosuppressive therapies, n (%)	21 (52.5)
Steroids, n (%)	7 (17.5)
Faecal calprotectin level at baseline, median (IQR) (µg/g)	1010.5 (357.8-1800.0)
CRP level at baseline, median (IQR) (mg/L)	13.2 (5.2-25.9)

SD: Standard deviation; IQR: Interquartile range; TNF: Tumor necrosis factor.

Table 2 Performances of Crohn’s disease activity index, C-reactive protein, and faecal calprotectin after 12 wk of anti-tumor necrosis factor to predict steroids-free remission at week 52

Endpoints	Sensitivity	Specificity	PPV	NPV	LR+	LR-	Accuracy
CDAI < 150	84.6% (56.3-96.6)	55.6% (37.3-72.4)	47.8% (27.4-68.2)	88.2% (72.9-100.0)	1.904 (1.177-3.081)	0.277 (0.074-1.035)	60.5% (50.2-79.8)
CRP ≤ 2.9 mg/L	92.3% (64.2-100.0)	74.1% (55.0-86.9)	63.2% (41.5-84.8)	95.2% (86.1-100.0)	3.560 (1.846-6.865)	0.104 (0.016-0.692)	80.0% (67.6-92.4)
CDAI < 150 and CRP ≤ 2.9 mg/L	76.9% (48.9-92.2)	85.2% (66.7-94.6)	71.4% (47.8-95.1)	88.5% (76.2-100.0)	5.192 (2.004-13.456)	0.271 (0.099-0.740)	82.5% (70.7-94.3)
Fcal < 300 µg/g	84.6% (56.3-96.6)	77.8% (58.8-89.6)	64.7% (42.0-87.4)	91.3% (79.8-100%)	3.808 (1.812-8.003)	0.198 (0.054-0.719)	80.0% (67.6-92.4)
Fcal improvement	76.9% (48.9-92.2)	92.6% (75.3-98.9)	83.3% (62.2-100.0)	89.3% (77.8-100.0)	10.385 (2.648-40.721)	0.249 (0.092-0.676)	87.5% (77.3-97.7)
CDAI < 150 and Fcal improvement	69.2% (42.0-87.4)	96.3% (79.9-100.0)	90.0% (71.4-100.0)	86.7% (74.5-98.8)	18.692 (2.640-132.328)	0.320 (0.141-0.725)	87.5% (77.3-97.7)
CDAI < 150 and CRP ≤ 2.9 mg/L and Fcal improvement	69.2% (42.0-87.4)	100.0% (84.9-100.0)	100.0% (100.0-100.0)	87.1% (75.3-98.9)	NA	0.308 (0.136-0.695)	90.0% (80.7-99.3)

CDAI: Crohn’s disease activity index; CRP: C-reactive protein; Fcal: Faecal calprotectin; PPV: Positive predictive valu; NPV: Negative positive value; LR+: Positive likelihood ratio; LR-: Negative likelihood ratio.