Lower Initial Insulin-like Growth Factor-Binding Protein-3 Concentrations May Reflect Immune Suppression and Predict Increased Risk of Sepsis-Related Mortality

Insulin-like growth factor-binding protein-3 (IGFBP-3) plays a vital role in cellular growth, development, and survival. Incorporating IGFBP-3 into baseline prognostic evaluations may enhance the prediction of mortality in patients with sepsis. In this study, serum levels of IGFBP-3, C-reactive protein, procalcitonin, lactate, interleukin-6, and mid-regional pro-adrenomedullin were measured upon admission to the internal medicine unit (IMU) in 139 patients with microbiologically confirmed sepsis. The objectives were as follows: (1) to classify septic patient phenotypes based on optimal thresholds of independent prognostic biomarkers and (2) to evaluate whether these biomarkers improve the predictive accuracy of a clinical model (Model 1), which includes the clinical predictors of 1-year mortality. Age, sequential organ failure assessment (SOFA) score, multiple sources of infection, and IGFBP-3 levels independently predicted 1-year mortality. Patients with IGFBP-3 levels below 10.64 had significantly lower median body temperature (p = 0.008), reduced lymphocyte count (p = 0.001), and higher 1-year mortality (p < 0.001). Model 1 included age, SOFA score, and the presence of multiple sources of sepsis as predictor variables. Model 2 incorporated the same variables as Model 1, with the addition of IGFBP-3 levels. When comparing their prognostic performance, Model 2 demonstrated superior predictive accuracy for mortality at 60, 90, and 365 days following admission to the IMU. Low IGFBP-3 levels at IMU admission are strongly associated with worse outcomes in septic patients, supporting its potential use as a prognostic biomarker.