Platelet indices at admission and their performance associated with predicting all-cause mortality in the ICU: a large cross-sectional cohort study

Platelet indices at admission offer the most opportune time for clinical decision-making, as they provide earliest insights, unlike later assessments during the intensive care unit (ICU) stay. There is emerging evidence suggesting the utility of platelet indices in predicting mortality. The objective of this study was, for the first time as far as the literature indicates, to elucidate the utility of seven platelet indices at admission in a large ICU cohort using Sysmex XN-series analysers. This cross-sectional study enrolled 592 ICU patients. The association of platelet indices at admission with the in-ICU and 90-day mortality was evaluated using logistic regression and receiver operating characteristic curve analysis. Of the platelet indices studied, absolute-immature platelet fraction (A-IPF), and mean platelet volume (MPV) and percentage-immature platelet fraction (%-IPF) were shown to be independently associated with predicting the in-ICU and 90-day mortality, respectively. The A-IPF cut-off value for predicting the in-ICU mortality was >6.4 × 10⁹/L (adjusted area under the curve (aAUC) 0.736, and adjusted Odds Ratio (aOR) 1.04), and the MPV and %-IPF cut-off values for predicting the 90-day mortality were >9.5 fL (aAUC 0.759, and aOR 1.26) and >6.3% (aAUC 0.762, and aOD 1.06), respectively (all <i>p</i> < 0.05). Admission A-IPF was the best predictor of in-ICU mortality, while admission MPV and %-IPF were the best predictors of 90-day mortality. These indices, all measured at admission, provide the earliest possible data relevant to mortality prediction. These are routinely available indices which deserve to be considered for new future ICU scoring systems.