Incidence and outcomes of heparin-induced thrombocytopenia in solid malignancy: an analysis of the National Inpatient Sample Database

Heparin-induced thrombocytopenia (HIT) is an immune-mediated adverse reaction to heparin products characterized by thrombocytopenia with or without thrombosis. This study aimed to determine the incidence, morbidity, mortality and economic burden of HIT in solid-malignancy-related hospitalizations. We analyzed the National Inpatient Sample Database (NIS), the largest public database of hospital admissions in the United States, from January 2012 to September 2015. The primary outcome of the study was the incidence of HIT. Secondary outcomes included incidence of venous thrombosis (acute deep venous thrombosis and pulmonary embolism), arterial thrombosis (thrombotic stroke, myocardial infarctions and other arterial thromboembolism), mortality associated with HIT, length of stay, total hospital charges and disposition. During the study period, 7 437 049 hospitalizations had an associated diagnosis of solid malignancy. Approximately 0·08% (n = 6225) hospitalizations had a secondary diagnosis of HIT in this population. The standardized incidence of total thrombotic events was higher in the solid malignancy with HIT compared to the solid malignancy without HIT group (24·7% vs. 6·8%, P < 0·001). The standardized mortality rate was 4·8% in solid malignancy with HIT compared to 3·4% in the without HIT group (OR, 1·53; 95% CI, 1·25-1·89; P < 0·001). HIT in solid malignancy is a rare condition but associated with increased morbidity and mortality.