Diagnostic validity and learning curve of non-NBI expert endoscopists in gastric intestinal metaplasia diagnosis.

BACKGROUND: Endoscopists' experience influences narrow-band imaging (NBI)-guided gastric intestinal metaplasia (GIM) diagnostic performance. We aimed to evaluate the general gastroenterologists (GE) performance in NBI-guided GIM diagnosis compared to NBI experts (XP) and assess GEs' learning curve. METHODS: A cross-sectional study was conducted between 10/2019 and 2/2022. Histology-proven GIM who underwent esophagogastroduodenoscopy (EGD) were randomly assessed by 2XPs or 3GEs. Endoscopists' performance on NBI-guided diagnoses were compared to the pathological diagnosis (gold standard) in five areas of the stomach according to the Sydney protocol. The primary outcome were GIM diagnosis validity scores of GEs compared to XPs. The secondary outcome was the minimum number of lesions required for GEs to achieve an accuracy of GIM diagnosis ≥ 80%. RESULTS: One thousand one hundred and fifty-five lesions from 189 patients (51.3% male, mean age 66 ± 10 years) were examined. GEs performed EGD in 128 patients with 690 lesions. the GIM diagnosis sensitivity, specificity, positive predictive value, negative predictive value, and accuracy of GEs compared to the XPs, were 91% vs.93%, 73% vs.83%, 79% vs.83%, 89% vs.93%, and 83% vs.88%, respectively. GEs demonstrated lower specificity (mean difference - 9.4%; 95%CI - 16.3, 1.4; p = 0.008) and accuracy (mean difference - 5.1%; 95%CI - 3.3, 6.3; p = 0.006) compared to XPs. After 100 lesions (50% GIM), GEs achieved an accuracy of ≥ 80% and all diagnostic validity scores were comparable to the XPs (p < 0.05 all). CONCLUSIONS: Compared to XPs, GEs had lower specificity and accuracy for GIM diagnosis. The learning curve for a GE to achieve comparable performance to XPs would necessitate at least 50 GIM lesions. Created with BioRender.com.

Immunogenicity and safety of heterologous versus homologous prime-boost schedules with inactivated and adenoviral vectored SARS-CoV-2 vaccines - A prospective multi-center study.

Background: During the peak of Coronavirus disease (COVID-19) pandemic in Thailand when the emergence of delta variant reduced the efficacy of inactivated vaccine, Thailand had abundance of inactivated vaccine but mRNA vaccine was not available and the supply of adenoviral-vectored vaccine was limited. The heterologous vaccination using CoronaVac and ChAdOx1-nCoV-19 vaccines was applied. We aim to compare the immunogenicity of immune response of primary vaccination with homologous ChAdOx1 nCoV-19 and heterologous vaccination with CoronaVac and ChAdOx1 nCoV-19. Methods: A total of 430 adults, scheduled to receive ChAdOx1-nCoV-19 as their second dose of primary COVID-19 vaccination, were enrolled. Participants were classified into two groups based on the first dose vaccine as CoronaVac (heterologous group) or ChAdOx1 nCoV-19 (homologous group). The primary outcome was antibodies to the SARS-CoV-2 spike protein receptor binding domain (anti-RBD) titres at 28 days after the second dose of vaccination. Secondary outcomes were anti-RBD titres at 90 days, surrogate viral neutralizing test (sVNT) at 28 and 90 days, and adverse events. Findings: In 358 participants with correct vaccine interval, the anti-RBD geometric mean titre ratio for the heterologous versus homologous group was 0.55 (95%CI; 0.44-0.067); p < 0.001 at day 28, and 0.80 (95%CI; 0.65-1.00); P = 0.05 at day 90. Median sVNT neutralizing activity was not significantly different in the heterologous versus homologous group at 28 days (93.5 vs 92.7 %); p = 0.13, but significantly higher in the heterologous group at day 90 (82.9 vs 76.4 %); p = 0.01. Interpretation: The homologous vaccination resulted in higher anti-RBD titres at 28 days after vaccination, but titres in the homologous group showed more rapid decline at 90 days. In the sVNT assay, median neutralization was similar at 28 days, but was longer-lasting and higher in the heterologous group at 90 days. Funding: This research received funding from the Royal College of Physicians of Thailand special grant 2021 for research initiative during COVID-19 pandemic.

Spot Hydrogen Breath Test for Predicting Response to Low Fermentable Oligo-, Di-, Mono-saccharides, and Polyols Dietary Advice in Patients With Bloating.

Background/Aims: An increase in postprandial intestinal gas plays a role in bloating symptoms. We aim to study the utility of spot breath hydrogen (H2) level in predicting the response to a low fermentable oligo-, di-, mono-saccharides, and polyols (FODMAPs) diet. Methods: Patients with functional gastrointestinal disorders diagnosed by Rome IV criteria with bothersome bloating for > 6 months were prospectively enrolled. Patients completed 7-day food diaries and collected a breath sample 2 hours after their usual lunch at baseline and 4 weeks after low FODMAPs dietary advice by a dietitian. The responder was defined as an improvement of ≥ 30% bloating scores in the fourth week. Results: Thirty-eight patients (32 female, 52.6 ± 13.8 years; 22 irritable bowel syndrome) completed the study. Twenty-one patients (55%) were classified as responders. Baseline global gastrointestinal symptoms, bloating, abdominal pain scores, and numbers of high FODMAPs items were similar between responders and non-responders. Both groups significantly decreased high FODMAPs items intake with similar numbers at the follow-up. The area under the curve for predicting low FODMAPs responsiveness using baseline H2 levels was 0.692 (95%CI, 0.51-0.86; P < 0.05), with the best cutoff at 8 parts per million (sensitivity 66.7%, specificity 82.4%). 66% of responders had baseline H2 level > 8 parts per million vs 17% of non-responders (P < 0.05). The baseline spot hydrogen level in responders was 9.5 (3.3-17.3) vs 4.5 (3.3-6.3) in non-responders (P < 0.05). Conclusions: A higher baseline breath hydrogen level was associated with bloating improvement after low FODMAPs dietary advice. A spot breath test after lunch, a simple point-of-care test, is possibly helpful in managing patients with bloating.