The relationship between prognosis and platelet count in patients with pneumonia

İntroduction: Pneumonia constitutes an important part of emergency department visits and in-hospital mortality. Platelets are inflammatory cells which play an important role in host defense. There are limited number of studies in the literature which are comparing the clinical outcomes of platelet counts and pneumonia patients. The primary endpoint of the study is to establish whether there is a relationship between platelet count and 30-day mortality, complicated clinical outcome (need for noninvasive and/or invasive mechanical ventilation, need for intensive care unit follow-up and vasopressor treatment), of patients diagnosed with pneumonia in emergency department. Materials and Methods: A prospective cross-sectional study of 18-year-old and older patients presenting with shortness of breath in emergency department and diagnosed with pneumonia. Between 07/02/2017-07/08/2017, who were referred to Dokuz Eylül University Medical Faculty Hospital Adult Emergency Service and evaluated clinically and radiologically as pneumonia without hematologic problems going with thrombocytosis or thrombocytopenia were included. The abnormal platelet count was <100.000/L (thrombocytopenia) and >400.000/L (thrombocytosis). Complicated clinical outcome and 30-day survival of patients according to platelet count and other laboratory parameters were examined. The parameters assessed in the surviving and non-surviving patient groups and in patients with normal or abnormal platelet counts were compared. Results: 405 patients aged 18-100 years included in the study, %58.8 (n=238) of the patients were male and the mean age was 75.1±12.7. %27.2 (n=110) of the patients were immobilized and %17.8 (n=72) were living in nursing homes. When the 30-day outcomes of the patients were examined, it was determined that 304 (%75.1) were hospitalized, 101 (%24.9) were discharged, 169 (%41.7) needed intensive care and 118 (%29.1) were died. Vasopressors were needed %18.5 (n=75) of the patients, noninvasive mechanic ventilation was needed %24.4 (n=99) of the patients, invasive mechanical ventilation was needed %25.9 (n=105) of the patients and tube thoracostomy was needed %4 (n=16) of the patients. At the time of admission, %14.1 (n=57) of patients had thrombocytosis and %4.2 (n=17) of patients had thrombocytopenia. The incidence of thrombocytosis was %14.2 (n=41) in surviving patients and %13.5 (n=16) in non-surviving patients.. The incidence of thrombocytopenia was %3.4 (n=10) in surviving patients and %5 (n=6 in non-surviving patients.. In the repeated complate blood count tests thrombocytosis was observed %27.7 (n=68) and thrombocytopenia was observed %10.2 (n=25) of the 245 patients. 76 patients were died who those measured the follow-up platelet count. In the follow-up platelet count the incidence of thrombocytosis was %25.3 (n=48) in surviving patients and %26.3 (n=20) in non-surviving patients. In the follow-up platelet count the incidence of thrombocytosis was %7.4 (n=14) in surviving patients and %14.4 (n=11) in non-surviving patients. There was no difference in 30-day mortality in patients who had thrombocytosis or thrombocytopenia on admission or follow-up. There was no difference between the platelet counts in the surviving and non-surviving patients. Systolic and diastolic blood pressures were found to be lower who had thrombocytopenia than in patients with who had thrombocytosis or normal platelet counts. Patients who had thrombocytopenia at the time of admission were found to have an increased need for invasive mechanical ventilation. Conclusion: We found that there was no relationship between platelet counts and in-hospital and/or 30-day mortality of patients who were diagnosed pneumonia in emergency department. In follow-up occuring thrombocytopenia may predict the need for invasive and/or noninvasive mechanical ventilation, vasopressor, and follow-up in intensive care unit. Key words: Pneumonia, platelet, mortality