Materials and methods

Study design and setting

We conducted a prospective, descriptive, and analytical pilot study over a six-month period, from June to December 2025, in the multidisciplinary intensive care unit of Ibn Sina University Hospital, Rabat, Morocco.

Study population

All consecutive adult patients (≥18 years) admitted to the intensive care unit with a diagnosis of septic shock were eligible for inclusion. Septic shock was defined according to the Sepsis-3 criteria, requiring the presence of sepsis associated with persistent hypotension necessitating vasopressor therapy to maintain a mean arterial pressure (MAP) of ≥65 mmHg despite adequate fluid resuscitation, along with hyperlactatemia [3]. Patients with incomplete clinical or biological data were excluded from the analysis.

Data collection

Demographic characteristics (age, sex), relevant medical history, and clinical data at admission were prospectively collected. Clinical parameters included the qSOFA score, hemodynamic variables, and neurological status. Blood lactate levels were measured at admission as part of routine clinical care. All data were anonymized and recorded in a standardized data collection form.

Outcome measure

The primary outcome of the study was 28-day in-hospital mortality, defined as death from any cause occurring within 28 days following intensive care unit admission.

Statistical analysis

Statistical analyses were performed using MedCalc® statistical software (MedCalc Software Ltd., Ostend, Belgium). Continuous variables were expressed as mean ± standard deviation or median with interquartile range (IQR), as appropriate. Comparisons between survivor and non-survivor groups were conducted using the Mann-Whitney U test for quantitative variables. The discriminatory ability of admission blood lactate to predict 28-day mortality was assessed using receiver operating characteristic (ROC) curve analysis, and the optimal cutoff value was determined using the Youden index. Logistic regression analysis was performed to identify factors associated with mortality. A p-value <0.05 was considered statistically significant.

Given the prospective, observational, and non-interventional design of the study, with data collected exclusively as part of routine clinical care and fully anonymized prior to analysis, the requirement for written informed consent was waived by the ethics committee, and no prior sample size calculation was performed.