The presence of idiopathic thrombocytopenic purpura correlates with lower rate of acute ST-elevation myocardial infarction

Background: Platelets are important in the pathogenesis of myocardial infarction (MI). We hypothesize that patients with acquired thrombocytopenia such as idiopathic thrombocytopenic purpura (ITP) may have lower MI rate. Materials & method: The Nationwide Inpatient Sample was used for this study. We analyzed the correlation between ST-elevation MI (STEMI) and ITP utilizing ICD-9 codes. Results: STEMI rate was lower in patients with ITP. We found that, in 2002, STEMI occurred in 0.64% of patients with ITP versus 0.89 (p < 0.007) and for 2011 0.30 versus 0.48 (p < 0.005). After adjusting for tobacco use, diabetes, hypertension, hyperlipidemia, gender and age, STEMI rate remained lower in ITP patients. Conclusion: ITP appears to be associated with lower STEMI rate suggesting low platelet count may exert protective effect from STEMI. Lay abstract: Background: Platelets are fragments of cells in our blood that play a role in the development of myocardial infarction (MI) aka heart attack. The association between medical conditions of low platelet number and MI is unknown. In order to answer this question, we analyzed data from a nationwide database to search for any correlation between a common type of MI called "STEMI" and a disease-state with low platelet number, namely idiopathic thrombocytopenic purpura (ITP). We found that the risk of STEMI was significantly reduced in patients with ITP between the years of 2002 and 2011 suggesting that ITP may exert a protective effect from the occurrence of this type of MI.