Gender and Racial Disparities in Risk and Outcomes of Thrombotic Thrombocytopenic Purpura Admissions: An Analysis of the National Inpatient Sample 2016-2019

Abstract

Introduction: Thrombotic thrombocytopenic purpura (TTP) is a rare disorder associated with severe deficiency in ADAMTS13 leading to microangiopathic hemolytic anemia, thrombocytopenia and end organ damage. The purpose of this study is to compare incidence and outcomes of TTP hospitalization between genders and races. Methods: We studied the National Inpatient Sample (NIS) from 2016 to 2019 for hospitalizations with the primary diagnosis of TTP. We fitted a multivariable logistic regression model to compare the risk of TTP amongst different races and genders. The model also accounted for age and comorbidities including solid or hematologic malignancies, history of thrombophilia, obesity, diabetes mellitus, hypertension, hyperlipidemia, chronic coronary artery disease, chronic liver disease, and chronic kidney disease. To compare mortality outcomes, we narrowed our analysis to TTP admissions only and fitted a multivariable logistic regression model with similar parameters. All reported confidence intervals were adjusted for multiplicity using the Bonferroni method. Results: A total of 7845 patients met the inclusion criteria of which 65.4% were female and 34.6% were males. The distribution of age and co-morbidities were different between the different racial groups. On adjusted analysis, females had higher rates of hospitalization due to TTP, with OR 1.32 (95% CI 1.24 to 1.41) compared to males, while there was no significant difference in mortality with OR 0.98 (95% CI 0.76 to 1.28). African American patients had significantly higher rates of hospitalization compared to Caucasian patients with OR of 3.62 (95% CI 3.38 to 3.88), followed by Asian and Hispanic patients respectively. Interestingly, the mortality in the African American patients was lower compared to Caucasian patients with OR of 0.74 (95% CI 0.55 to 0.98). There was no significant difference in mortality in other races. Conclusion: African American patients and females experienced significantly higher rates of hospitalization with TTP. However, African American patients experienced lower mortality. More research is needed to understand the cause behind these differences and modify our diagnostic and management to improve outcomes for patients with TTP.