Background: Prior case reports and case-series reports have shown an association between Opioid use disorder and Thrombotic Thrombocytopenic Purpura (TTP). However, clinical data regarding Thrombotic Thrombocytopenic Purpura co-existing with Opioid use disorder are still lacking in the literature. We aim to study patient characteristics, epidemiology, co-morbidities, and clinical outcomes in these patients.

Methods: We analyzed adult hospitalizations with a principal and secondary diagnostic ICD 9 code indicating Thrombotic Thrombocytopenic Purpura using datasets from 2012 to 2014 National inpatient sample (NIS). Elective hospitalizations were excluded. We compared the baseline characteristics of TTP admissions with or without a co-existing diagnosis of opioid use disorder. International Classification of Diseases, Ninth Revision, Clinical Modification/Procedure Coding System (ICD-9-CM) to identify co-morbid conditions and TTP associated in-hospital complications. Multivariate regression analysis was performed using STATA 16.0 to determine the relationship of outcomes. P-value <0.05 was used as the significance threshold.

Results: From 2012 to 2014, 8,930 adults were admitted with a principal or secondary diagnosis of TTP. Among them, 205 (2.3%) had a concomitant diagnosis of opioid use disorder. When compared to the group without opioid use disorder, patient with opioid use disorder were younger (mean age 34.7 vs. 48.9, p<0.05), predominantly Caucasians (88.2% vs. 47.7%, p<0.05), using Medicaid (53.9% vs. 22.1%, p<0.05), less likely have diabetes (4.9% vs. 18.8%, p<0.05). After adjusting for patient and hospital-level confounders, patients with TTP and opioid use disorder had significantly higher odds of having delirium [adjusted odds ratio (aOR)18.2, 95% CI 2.21- 148.83, p<0.05]. No statistically significant difference was seen in rates of developing acute kidney injury, deep vein thrombosis/ pulmonary embolism (DVT/PE), the requirement of mechanical ventilation, length or cost of stay between the two groups.

Conclusions: Our study is the first population-based retrospective study of opioid use disorder in hospitalized patients with TTP in the United States. Our findings suggest that patients with opioid use disorder had a higher chance of delirium diagnosis if they develop TTP. Patients who develop TTP with co-existing opioid use were younger, Caucasians, likely to be on Medicaid, and less likely to have diabetes. Opioid use is not associated with an increased likelihood of acute kidney injury, DVT/PE, the requirement of mechanical ventilation, increase in hospital length of stay, and cost. However, long-term data still lacks in the literature, and further research is needed to provide instructions regarding the use of medications that alter the level of consciousness.