Trends and outcomes of new-onset thrombocytopenia in hospitalized patients: a secondary care center experience

Background: Thrombocytopenia is common among hospitalized patients and is associated with increased morbidity, prolonged hospitalization, and mortality. It may result from infection, sepsis, medications, disseminated intravascular coagulation (DIC), or other acute conditions. However, data on new-onset thrombocytopenia in secondary care hospitals in Saudi Arabia are limited. This study assessed its incidence, severity, etiology, and clinical outcomes in hospitalized adults. Methods: This retrospective study was conducted at Security Forces Hospital, Makkah, Saudi Arabia, from January 2020 to December 2024. A total of 392 adult inpatients who developed new-onset thrombocytopenia (platelet count <150×10⁹/l) after admission were included using consecutive sampling. Patients with pre-existing thrombocytopenia, hematological malignancies, or recent chemotherapy were excluded. Demographic, clinical, laboratory, and outcome data were extracted from medical records. Thrombocytopenia severity and underlying etiologies were classified according to clinical and laboratory findings. Results: Sepsis was the leading cause of new-onset thrombocytopenia (34.7%), followed by viral infections (19.6%), drug-induced thrombocytopenia (12.5%), and DIC (11.2%). Severe thrombocytopenia occurred in 26.5% of patients. ICU admission was required in 38.8%, while in-hospital mortality was 21.4%. Mortality was particularly higher among patients with sepsis-related and severe thrombocytopenia, highlighting the prognostic significance of both the underlying cause and degree of platelet reduction. Conclusions: New-onset thrombocytopenia during hospitalization is associated with substantial morbidity and mortality. Early recognition, close monitoring, and prompt identification of underlying causes may improve outcomes, particularly in resource-limited secondary care settings.