Intest Res.  2024 Oct;22(4):464-472. 10.5217/ir.2023.00139.

Efficacy of serum leucine-rich alpha-2 glycoprotein in predicting findings of Crohn’s disease small bowel lesion in capsule endoscopy

• Omori T
• Koroku M
• Murasugi S
• Ito A
• Yonezawa M
• Nakamura S
• Tokushige K

• KMID: 2560296
• DOI: http://doi.org/10.5217/ir.2023.00139

Abstract

Background/Aims
Small bowel capsule endoscopy (SBCE) is an evaluation method for small bowel (SB) lesions in Crohn’s disease (CD). However, the relationship between SBCE findings and the serological biomarker leucine-rich alpha-2 glycoprotein (LRG) remains unclear. We aimed to establish appropriate cutoff values of LRG to predict the presence of SB lesions in CD through SBCE.
Methods
Patients with CD with SB lesions who had undergone SBCE and LRG measurements 1 month before and after the SBCE were included. The LRG values for ulcers ≥0.5 cm and other inflammatory lesions noted in SBCE were determined using the Youden Index, and the sensitivity and specificity were calculated. Additionally, the correlation between the SBCE scores (CD Activity in Capsule Endoscopy) and LRG values was evaluated.
Results
Forty patients without active colorectal lesions were included in the study. When the cutoff value of LRG for SB ulcers ≥ 0.5 cm was set at 14 μg/mL, the sensitivity was 92.3%, specificity was 81.5%, positive predictive value (PPV) was 70.6%, and negative predictive value (NPV) was 95.7%. In contrast, an LRG cutoff value of 12 μg/mL without inflammatory findings had a sensitivity of 91.7%, specificity of 82.1%, PPV of 68.8%, and NPV of 95.8%. CD Activity in Capsule Endoscopy correlated well with LRG values (Spearman’s rank correlation coefficient ρ = 0.681, P< 0.001).
Conclusions
An LRG cutoff value of 14 μg/mL may be useful in predicting the presence of SB ulcers ≥ 0.5 cm, and an LRG cutoff value of 12 μg/mL may be useful in predicting the absence of SB inflammatory findings.

Keyword

Capsule endoscopy; Leucine-rich alpha-2 glycoprotein; Crohn’s disease activity in capsule endoscopy; Crohn disease; Small bowel

Figure

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  Fig. 1. Study profile. Intestinal patency was evaluated by patency capsule in all cases. CD, Crohn’s disease; SB, small bowel; SBCE, SB capsule endoscopy; LRG, leucine-rich alpha-2 glycoprotein.

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  Fig. 2. Receiver operating characteristic curve of CDAI, CRP, and LRG for small bowel ulcer (≥0.5 cm). The highest AUC value was 0.92 at an LRG value of 14 μg/mL. CDAI, Crohn’s Disease Activity Index; CRP, C-reactive protein; LRG, leucine-rich alpha-2 glycoprotein; AUC, area under the curve.

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  Fig. 3. Receiver operating characteristic curve of leucine-rich alpha-2 glycoprotein (LRG) levels for the absence of small bowel inflammatory findings in patients with Crohn’s disease. The maximum area under the curve (AUC) value was 0.87 at an LRG value of 12 μg/mL.

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  Fig. 4. Correlation between CDACE and LRG (Spearman's rank correlation coefficient). CDACE, Crohn’s Disease Activity in Capsule Endoscopy; LRG, leucine-rich alpha-2 glycoprotein.

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  Fig. 5. Prediction of the presence of SB lesions based on LRG values and proposed interpretation. aMinor inflammatory lesions: edema, erythema, erosions (<0.5 cm mucosal lesions). SB, small bowel; SBCE, SB capsule endoscopy; LRG, leucine-rich alpha-2 glycoprotein; PPV, positive predictive value; NPV, negative predictive value; +LR, positive likelihood ratio; –LR, negative likelihood ratio.

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