Lactate-to-Albumin Ratio Flags Mortality Risk in Sepsis-Induced Myocardial Injury

Critically ill patients whose sepsis damages the heart face sharply elevated odds of death, and a simple calculation dividing blood lactate by blood albumin may help identify those at greatest risk. A retrospective cohort study published in BMC Immunology analyzed data from 836 adults with sepsis-induced myocardial injury (SIMI) drawn from the MIMIC-IV database and found that those in the highest quartile of the lactate-to-albumin ratio, or LAR, had more than three times the mortality risk of those in the lowest quartile.

SIMI was defined in the study as a cardiac troponin T level above 0.01 ng/mL. The researchers calculated LAR using the first serum lactate (in mmol/L) and serum albumin (in g/dL) measurements obtained within 24 hours of ICU admission. The ratio is intended to integrate two biological signals: lactate, a marker of tissue hypoperfusion, and albumin, which the authors describe as reflecting systemic inflammation. Specific prognostic indicators for SIMI remain scarce, which motivated the analysis.

The primary endpoint was 28-day all-cause mortality; the secondary endpoint was 90-day mortality. Of the 836 patients, 273 (32.7%) died within 28 days and 349 (41.7%) died within 90 days. Patients were divided into four groups based on LAR quartiles, and associations with mortality were evaluated using multivariable Cox proportional-hazards regression, reporting hazard ratios, and logistic regression, reporting odds ratios.

In the fully adjusted Cox model, the highest LAR quartile compared with the lowest was associated with significantly increased mortality: a hazard ratio of 3.331 (95% confidence interval 1.917–5.787) for 28-day mortality and 2.907 (95% CI 1.855–4.556) for 90-day mortality, both with p < 0.001. Logistic regression produced consistent results, with an odds ratio of 4.78 (95% CI 2.55–9.46) for 28-day mortality and 4.32 (95% CI 2.43–7.89) for 90-day mortality. Restricted cubic splines confirmed a graded, monotonically increasing dose-response relationship between LAR and death risk.

The team also tested how well LAR performed as a predictor. In a test set, a multiple-marker model incorporating LAR showed discriminative performance essentially identical to LAR alone for 28-day mortality, with an area under the receiver operating characteristic curve of 0.694 versus 0.693. However, the multiple-marker model consistently outperformed conventional ICU severity scores, and decision-curve analysis indicated superior net clinical benefit across a wide range of threshold probabilities.

Subgroup analyses suggested the prognostic value of LAR remained robust across most clinical strata examined, including older patients, those with liver disease, those with respiratory failure, and patients in higher severity score categories. This consistency across subgroups is notable given the heterogeneity typical of critically ill sepsis populations.

The authors conclude that LAR is a robust, independent, and dose-dependent predictor of short- and medium-term mortality in SIMI patients, with performance comparable to established severity scores and additional net benefit when incorporated into a multi-marker model. Because lactate and albumin are low-cost, routinely available laboratory tests, the ratio could be calculated quickly at the bedside without new infrastructure.

Important limitations temper these findings. The study is retrospective and uses a single database, so the authors explicitly call for prospective studies to externally validate the results and to determine whether LAR-guided management strategies actually improve clinical outcomes. An association between a biomarker and mortality, even one that is dose-dependent and statistically robust after adjustment, does not by itself establish that measuring LAR changes patient care. The predictive performance, with an AUC around 0.69, is moderate rather than definitive, meaning LAR would supplement rather than replace clinical judgment and existing scoring tools.

Nevertheless, the study adds to a growing body of retrospective MIMIC-IV analyses examining the lactate-to-albumin ratio in other critically ill groups, including patients with heart failure with preserved ejection fraction, trauma and surgical ICU patients, and those with acute myocardial infarction. If prospective validation confirms these results, LAR could offer an inexpensive early warning signal for clinicians caring for septic patients with cardiac injury, helping flag those who may warrant closer monitoring in the first days of intensive care.

Subject of Research: The lactate-to-albumin ratio as a prognostic marker for short- and medium-term mortality in sepsis-induced myocardial injury.

Article Title: The lactate-to-albumin ratio for mortality risk stratification in sepsis-induced myocardial injury: a retrospective cohort study

Article References: Zhuang, Y., Gong, W., Chen, X., & Ye, R. (2026). The lactate-to-albumin ratio for mortality risk stratification in sepsis-induced myocardial injury: a retrospective cohort study. BMC Immunology. https://doi.org/10.1186/s12865-026-00914-9

Image Credits: AI Generated

DOI: 10.1186/s12865-026-00914-9

Keywords: sepsis-induced myocardial injury, lactate-to-albumin ratio, mortality risk stratification, MIMIC-IV database, retrospective cohort study, biomarker, ICU, cardiac troponin T, prognosis, critical care, lactate-to-albumin, ratio