Background Thrombotic Thrombocytopenic Purpura (TTP) is a rare and serious thrombotic microangiopathy that's defined by the confirmation of blood clots throughout the body, leading to a low platelet count (thrombocytopenia) and implicit organ damage. Plasmapheresis (also known as plasma exchange or PEX) is the primary life-saving therapy when it comes to treating patients with TTP. Although prior literature showed a significant reduction in mortality due to plasmapheresis, there is still limited data on how it affects hospital outcomes like mortality, complications, and length of stay on a national scale. This study aimed to assess the role of plasmapheresis in reducing mortality and its effect on in-hospital complications and length of stay in patients hospitalized with TTP using nationally representative data over the span of seven years. Methods We conducted a retrospective cohort analysis using the National Inpatient Sample (NIS) over the span of seven years from 2016 to 2022. Adult hospitalizations with a diagnosis of Thrombotic Thrombocytopenic Purpura (TTP) were identified using the ICD-10-CM code M31.1, whereas the procedure of Plasmapheresis was identified using ICD-10-PCS procedure codes 6A550Z3 and 6A551Z3. We applied integrated discharge weights, strata, and cluster variables to generate nationally representative estimates per the NIS survey design. Hospitalizations were stratified into two groups, which included those who underwent plasmapheresis (PEX group) and those who did not (non-PEX group).

The primary outcomes studied included the in-hospital mortality and average length of stay (LOS), whereas the secondary outcomes included in-hospital complications. Covariates include demographic variables (age, sex, race), socioeconomic indicators (median income quartile, primary payer), hospital characteristics (region, teaching status, bed size), and comorbidity burden measured using the Charlson Comorbidity Index. Survey-adjusted logistic regression was used for binary outcomes (e.g., mortality, complications), while linear regression was used for continuous outcomes (e.g., LOS). Results were reported as adjusted odds ratios (aOR) or adjusted mean differences with 95% confidence intervals (CI). A p-value <0.05 was considered statistically significant. All of the analyses were performed using StataMP version 17.Results Out of 13,430 nationally weighted hospitalizations with a diagnosis of TTP, 7,685 received plasmapheresis. Patients in the plasmapheresis group were more likely to be female (67.5% vs. 62.2%; p = 0.0039), and more frequently black (47.1% vs. 40.1%; p = 0.0002). TTP patients with PEX were also more frequently treated in urban teaching hospitals (90.7% vs 84.98; p <0.0001).

Patients treated with Plasmapheresis had a lower overall comorbidity burden, with 83.5% having a Charlson Comorbidity Index of 0-3 compared to 76.8% in the non-PEX group (p < 0.0001). The rates of obesity (13.9% vs. 8.5%; p < 0.0001) and hypertension (38.3% vs. 34.4%; p = 0.0443) were higher among those receiving plasmapheresis, whereas cancer (6.3% vs. 12.1%; p < 0.0001) and congestive heart failure (5.7% vs. 8.9%; p = 0.0011) were more prevalent in the non-PEX group.

After multivariable adjustment, plasmapheresis was associated with significantly lower odds of in-hospital mortality (aOR: 0.46; 95% CI: 0.33–0.66; p < 0.0001) and a longer average length of stay (adjusted mean difference: 3.22 days; 95% CI: 2.31–4.12; p < 0.0001).Conclusion In this nationally representative study of 13,430 hospitalizations with TTP, patients who had the procedure of plasmapheresis were more frequently female and Black. Patients who received plasmapheresis showed an overall lower comorbidity burden, yet they possessed higher rates of hypertension and obesity, while the TTP patients who didn't receive the treatment were increasingly affected by cancer and congestive heart failure.

The PEX procedure was strongly associated with a lower risk of in-hospital death, though patients who received it tended to stay longer in the hospital. These findings highlight the life-saving value of the plasmapheresis procedure in patients with Thrombotic Thrombocytopenic Purpura and also strongly emphasize the need for quicker diagnosis and equal access to this treatment.

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2025
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