Platelet counts and its course for predicting in-hospital mortality in intensive care unit

Background & Aims: Recent studies have shown that thrombocytopenia (TP) is associated with poor outcomes in patients with pneumonia, burns, and H1N1 influenza. The aim of this study is to determine the impact of platelet count trends and TP on mortality in intensive care unit (ICU) patients. Materials & Methods: TP was defined as <150,000 platelets/ml. In this study, 300 patients who had been admitted to the ICU for internal diseases were evaluated for platelet counts on the day of admission and following days to assess the presence of TP. Comparisons were made between patients who died in the ICU and those who were discharged for presence of TP, mean platelet counts, and changes in platelet counts. Platelet count trends were evaluated with repeated measurement tests. P < 0.05 was significant. Results: Of 300 patients, 131 (43.7%) had TP upon admission to the ICU. The rates of TP were 60% among patients who died as compared to 34% among surviving patients (p < 0.001, risk ratio = 3.07, 95% CI 1.88–5.01). Mean platelet counts on admission day and all four of the following days were significantly lower in patients who died than patients who survived (p < 0.001). On the days after admission, platelet counts tended to increase in surviving patients and decreased among non-surviving patients. Conclusion: TP is commonly observed in ICU patients. TP diagnosis and trends of decreasing platelet counts over time are each predictors of mortality among ICU patients. Because platelet counts are inexpensive and readily available, our findings suggest that their use helps inform clinical decision-making in patients with critical illness.