Koo, Thai Hau

ABSTRACT Background and Aim Determining the location of gastrointestinal (GI) bleeding is critical for guiding diagnostic and therapeutic strategies but often results in patients receiving pan‐endoscopy with upper endoscopy, colonoscopy, and small bowel capsule endoscopy, which can be unnecessary, costly, and waste limited healthcare resources. The blood urea nitrogen‐to‐creatinine ratio (BUN/Cr) may help discriminate between upper GI bleeding (UGIB) and lower GI bleeding (LGIB). This study aims to assess the diagnostic performance of the BUN/Cr in distinguishing UGIB from LGIB. Methods A literature search was conducted in MEDLINE, EMBASE, and Cochrane Library to identify diagnostic test accuracy studies published from inception through January 31, 2025, which evaluated BUN/Cr in patients with UGIB versus LGIB. A linear mixed‐effects model meta‐analysis was conducted using the “diagmeta” package. The pooled sensitivity, specificity, diagnostic odds ratio, and area under the summary receiver operating characteristic curve (AUC) were estimated, and optimal threshold was determined using the Youden index. Results Seventeen studies were included in this meta‐analysis. The pooled mean difference in BUN/Cr between UGIB and LGIB patients was 11.44 (95% confidence interval [95% CI] 8.35–14.52). At a threshold of > 30, pooled sensitivity was 38.8% (95% CI 28.1%–50.8%) and specificity was 89.3% (95% CI 81.0%–94.2%). At the optimal cut‐off of 22, sensitivity was 66.2% (95% CI 57.8%–73.7%), specificity was 71.0% (95% CI 58.5%–81.0%), and AUC was 0.740 (95% CI 0.683–0.794). Conclusion BUN/Cr demonstrates moderate diagnostic accuracy for distinguishing UGIB from LGIB, particularly at a threshold of ≥ 22. This readily accessible and inexpensive blood test may assist in early clinical triage and assessment of the location of GI bleeding, particularly in those patients where the clinical presentation is obscure.

Motility disorders, particularly gastroparesis, are prevalent complications following solid organ transplantation, significantly impacting quality of life, nutritional status, graft survival, and mortality. This comprehensive review synthesises evidence from PubMed, Scopus, and Embase databases on pathophysiology, clinical manifestations, diagnosis, management, and prognostic factors across transplant types. Mechanisms include vagal nerve injury (highest in lung transplants, prevalence 40–91%), immunosuppressive effects (e.g., tacrolimus accelerates motility; mycophenolate impairs it), surgical trauma, microbiome dysbiosis (reduced Firmicutes/Bacteroidetes ratio), and metabolic factors like post-transplant diabetes (OR 5.17 in kidney recipients). Pediatric and thoracic recipients face the highest risks, with lung transplant gastroparesis conferring a 2.7-fold increased mortality/retransplantation hazard (p < 0.05). Diagnosis relies on gastric emptying scintigraphy (gold standard, sensitivity 85–95%) and wireless motility capsules (100% sensitivity for delay), while management encompasses prokinetics (60–80% response), endoscopic G-POEM (85% success), gastric electrical stimulation (100% quality-of-life improvement in series), and nutritional support. Prognostic factors include younger age (better intervention response), aetiology (anatomical worse than metabolic), and early therapy success. Outcomes vary: lung recipients experience severe impacts on chronic allograft dysfunction (83% oesophageal motility abnormalities correlate with 66–67% rejection). Future directions emphasise microbiome therapies, AI predictive models (AUC 0.85), and wearables for continuous monitoring. Multidisciplinary approaches are essential to balance immunosuppression with GI management, addressing ethical dilemmas like drug interactions and access disparities. Ultimately, early screening and personalised interventions can mitigate complications, enhancing long-term transplant success.

Background/Objectives: Coronavirus disease 2019 (COVID-19) is associated with gastrointestinal (GI) symptoms. Small intestinal bacterial overgrowth (SIBO) is emerging as a significant GI sequela post-COVID-19 infection. This study aimed to evaluate the prevalence and incidence of SIBO post-COVID-19 infection across different age groups and to identify associated risk factors in a global cohort. Methods: A retrospective study utilized the TriNetX database and included adult patients (≥18 years) diagnosed with SIBO following COVID-19 infection (1 January 2022–30 May 2024). A propensity score matching (1:1) was used to adjust for demographics and SIBO risk factors. Kaplan–Meier survival analysis assessed the SIBO incidence within 12 months. Results: Among 1,660,092 COVID-19 patients and 42,322,017 controls, SIBO was diagnosed in 353 COVID-19 patients without hydrogen breath tests (BT) and 78 with BT, compared to 3368 controls without BT and 871 with BT. Age-specific analysis demonstrated a clear, progressive increase in the SIBO incidence, becoming distinctly significant by 6 months and highest at 12 months post-infection. The highest risks were noted in ages 60–69 (0.011% vs. 0.004%, OR 2.6, p = 0.0003) and 70–79 (0.011% vs. 0.005%, OR 2.0, p = 0.0004), with younger age groups (30–49 years) also showing significantly increased risks. The medication analysis revealed strong associations with chronic opioid, proton pump inhibitor, and antidiarrheal medication. Conclusions: COVID-19 significantly increased the risk of SIBO, particularly within the first 12 months post-infection, across various age groups and, notably, in association with certain chronic medications. Clinical vigilance and targeted management strategies are recommended to mitigate long-term GI consequences.