Correlation Between Anteroposterior/Transverse Ratio of Inferior Vena Cava Diameter on Computed Tomography and Prognosis in Patients With Sepsis: A Single-Center Retrospective Cohort Study.

Background Sepsis is a life-threatening condition with high mortality, and accurate early prognostication remains difficult. The anteroposterior-to-transverse (AP/T) diameter ratio of the inferior vena cava (IVC), measured on computed tomography (CT), offers a simple, objective indicator of intravascular volume status and may correlate with outcomes. Objectives To assess whether a lower CT-derived IVC AP/T diameter ratio - used as a surrogate for intravascular volume status - is associated with increased 30-day all-cause mortality in adult sepsis patients and to evaluate whether stratification using an optimal cutoff can differentiate mortality risk. Methods In this single-center retrospective cohort study, we included adult patients diagnosed with sepsis from April 1, 2020 to April 1, 2023. The IVC AP/T ratio was measured on CT scans just below the renal veins. The primary outcome was 30-day all-cause mortality. A receiver operating characteristic (ROC) analysis identified the optimal cutoff, and patients were stratified accordingly to compare mortality. Results Of 435 patients, 396 had evaluable CT data. The overall 30-day mortality rate was 20.6%. Non-survivors had a significantly lower median IVC AP/T ratio than survivors (0.401 vs. 0.525, p<0.001). In multivariable logistic regression incorporating age, serum lactate, components of the Sequential Organ Failure Assessment (SOFA) score, and the IVC AP/T ratio, the AP/T ratio was not identified as an independent predictor of mortality. The receiving operator characteristic (ROC) analysis yielded an area under the curve (AUC) of 0.64, identifying 0.44 as the optimal cutoff. At this threshold, the accuracy was 63.5%, sensitivity 61.7%, and specificity 68.6%. Patients with an AP/T ratio ≤0.44 were found to have significantly higher mortality than those with a ratio >0.44 (33.6% vs. 12.6%, p<0.001). Conclusions The IVC AP/T ratio assessed via CT was significantly associated with 30-day mortality in univariate analysis and may help stratify sepsis patients into different risk categories. However, it was not identified as an independent predictor in multivariable analysis, and its discriminatory ability was modest (AUC 0.64). These findings suggest that while the metric is not sufficient as a standalone predictor, it may serve as a supplementary risk indicator. Further prospective, multicenter studies are warranted to validate its clinical utility and integration into existing prognostic models.