J Neurogastroenterol Motil  https://doi.org/10.5056/jnm19113
Breath Tests for the Non-invasive Diagnosis of Small Intestinal Bacterial Overgrowth: A Systematic Review With Meta-analysis
Giuseppe Losurdo1, Gioacchino Leandro2, Enzo Ierardi1, Francesco Perri3, Michele Barone1, Mariabeatrice Principi1, and Alfredo Di Leo1*
1Section of Gastroenterology, Department of Emergency and Organ Transplantation, University “Aldo Moro”, Piazza Giulio Cesare, Bari, Italy; 2Gastroenterology Unit, National Institute of Research for Gastroenterology “Saverio De Bellis”, Castellana Grotte, Bari, Italy; and 3Digestive Endoscopy Unit, National Institute of Research “Casa Sollievo della Sofferenza”, San Giovanni Rotondo, Foggia, Italy
Correspondence to: Alfredo Di Leo, MD, PhD
Section of Gastroenterology, Department of Emergency and Organ Transplantation, University “Aldo Moro”, Piazza Giulio Cesare 11, 70124 Bari, Italy
Tel: +39-080-559-3452, Fax: +39-080-559-3088, E-mail: alfredo.dileo@uniba.it
Received: May 22, 2019; Revised: August 29, 2019; Accepted: September 20, 2019; Published online: November 19, 2019.
© The Korean Society of Neurogastroenterology and Motility. All rights reserved.

Small intestinal bacterial overgrowth (SIBO) diagnosis is usually based on non-invasive breath tests (BTs), namely lactulose BT (LBT) and glucose BT (GBT). However, divergent opinions and problems of parameter standardization are still controversial aspects. We aim to perform a meta-analysis to analyze diagnostic performance of LBT/GBT for SIBO diagnosis.
We searched in main literature databases articles in which SIBO diagnosis was achieved by LBT/GBT in comparison to jejunal aspirate culture (reference gold standard). We calculated pooled sensitivity, specificity, positive, and negative likelihood ratios and diagnostic odd ratios. Summary receiver operating characteristic curves were drawn and pooled areas under the curve were calculated.
We selected 14 studies. Pooled sensitivity of LBT and GBT was 42.0% and 54.5%, respectively. Pooled specificity of LBT and GBT was 70.6% and 83.2%, respectively. When delta over baseline cut-off > 20 H2 parts per million (ppm) was used, GBT sensitivity and specificity were 47.3% and 80.9%; when the cutoff was other than and lower than > 20 ppm, sensitivity and specificity were 61.7% and 86.0%. In patients with abdominal surgery history, pooled GBT sensitivity and specificity gave the impression of having a better performance (81.7% and 78.8%) compared to subjects without any SIBO predisposing condition (sensitivity = 40.6% and specificity = 84.0%).
GBT seems to work better than LBT. A cut-off of delta H2 expired other than and lower than > 20 ppm shows a slightly better result than > 20 ppm. BTs demonstrate the best effectiveness in patients with surgical reconstructions of gastrointestinal tract.
Keywords: Breath tests, Glucose, Hydrogen, Lactulose, SIBO

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