Systematic reviews and meta-analyses are essential tools in medical research. Systematic reviews are a type of literature review that uses a systematic process to identify and assess all available literature on a specific research question. A meta-analysis is a statistical method of synthesizing the results of a systematic review by quantitatively combining data. The process begins with formulating a well-defined research question using frameworks. Comprehensive literature searches across multiple databases, including PubMed, Embase, and Cochrane, to ensure the inclusion of diverse studies. Tools like EndNote and Covidence streamline reference management and study selection, enhancing efficiency and accuracy. Quality assessment using tools like the Cochrane Risk of Bias Tool and Newcastle-Ottawa Scale is crucial to evaluate the methodological rigor. Data extraction, using standardized forms to ensure consistent information capture. Qualitative synthesis is one method that integrates the results of a systematic review focusing on textual data. Meta-analysis employs statistical software such as R and RevMan to compute effect sizes, confidence intervals, and assess heterogeneity. Visual representations, including forest and funnel plots, facilitate the interpretation of results. Challenges such as publication bias and heterogeneity are addressed using statistical methods like Egger regression and the trim-and-fill technique. Sensitivity analyses further validate the robustness of findings. Common errors, including data entry mistakes and inappropriate pooling, are mitigated through rigorous methodological adherence and critical self-evaluation. Meticulously conducted, systematic reviews and meta-analyses represent the pinnacle of the evidence hierarchy, driving advancements in medical research and practice.

Background: Hypoxic hepatitis (HH), also termed ischemic hepatitis and historically described as shock liver, is an acute liver injury syndrome in critically ill patients characterized by a rapid and marked rise in aminotransferases in the setting of circulatory, cardiac, or respiratory failure, after exclusion of other causes of acute hepatic injury. Despite its clinical relevance, the true incidence and prognostic significance of HH remain unclear. This systematic review and meta-analysis aimed to determine the pooled incidence, mortality, and outcomes of HH in critically ill patients. Methods: This study followed PRISMA guidelines and was registered in PROSPERO (CRD420251088120). A systematic search of PubMed, Scopus, Web of Science, EMBASE, Cochrane, LILACS, CNKI, and Google Scholar was conducted on July 4, 2025. Randomized, cohort, and case-control studies involving critically ill adults were included. Primary outcomes were HH incidence and mortality; secondary outcomes included length of stay, organ support, and comparisons with non-HH patients. Random-effects meta-analyses were performed, with heterogeneity assessed using I ² statistics. Results: Of 3236 records, 25 studies (150,928 patients) met inclusion criteria. The pooled prevalence of HH in ICU patients was 8.3%, and all-cause mortality was 64.0%. Compared with non-HH patients, HH was associated with higher all-cause mortality (RR 2.94). Mechanical ventilation (RR 2.44) and renal replacement therapy (RR 3.80) showed elevated but statistically non-significant associations. Cardiogenic shock, cardiac arrest, and sepsis were the leading reported precipitants. Conclusion: HH affects a substantial proportion of ICU patients and is consistently associated with adverse outcomes and greater organ support use. However, the available evidence supports HH primarily as an associated prognostic marker rather than a proven causal determinant of mortality. Findings should be interpreted cautiously because of high heterogeneity, potential residual confounding, and possible publication bias. Standardized diagnostic criteria and prospective studies evaluating incremental prognostic value beyond established ICU severity scores are needed.

Background: Hypoxic hepatitis (HH), also termed ischemic hepatitis or shock liver, is an acute hepatocellular injury caused by an imbalance between hepatic oxygen supply and demand. It develops secondary to cardiac, circulatory, or respiratory failure through reduced hepatic blood flow, systemic hypoxemia, hepatic venous congestion, or impaired cellular oxygen utilization. Although its recognition in critical care has increased, the clinical and biochemical factors distinguishing survivors from non-survivors remain poorly defined. This analysis aimed to characterize these differences among critically ill adults diagnosed with HH. Methods: This systematic review and meta-analysis followed PRISMA guidelines and was pre-registered in PROSPERO (CRD420251180238). A comprehensive search of PubMed, Scopus, Web of Science, EMBASE, Cochrane, LILACS, CNKI, CINAHL, and Google Scholar was conducted on July 4, 2025. Eligible studies included critically ill patients diagnosed with HH. Random-effects meta-analyses were performed in R. Results: Of 3236 identified records, five cohort studies comprising 107,346 participants were included. The pooled mean difference in age between survivors and non-survivors was −5.1 years (p = 0.03; I ² = 23.1%). Mechanical ventilation was associated with lower survival (RR = 0.76; p < 0.01; I ² = 0.7%), and norepinephrine or other hemodynamic support was associated with lower odds of survival (OR = 0.4; p < 0.01; I ² = 5.5%). In contrast, lactate, bilirubin, and INR were not significantly associated with survival. Conclusion: Hypoxic hepatitis should be interpreted primarily as a secondary marker of severe cardiac, circulatory, or respiratory failure rather than as an isolated primary driver of mortality. Its occurrence may be associated with increased mortality in critically ill patients; however, the available evidence is limited by the small number of eligible studies and heterogeneity. Further standardized, prospective studies are needed to clarify its independent prognostic significance.