Immune Thrombotic Thrombocytopenic Purpura in Elderly Patients: The Roles of PLASMIC and French Scores

Objective: In recent years, new developments have been incorporated into daily practice in the management of immune thrombotic thrombocytopenic purpura (iTTP). In particular, clinical scoring systems could help clinicians with clinical decision-making and early recognition. However, older patients frequently present with more organ involvement and in unusual ways. The ways in which age could affect these clinical prediction scoring systems remain unclear. We evaluated the use of PLASMIC and French scores in patients over 60 years of age. Materials and Methods: We performed a retrospective cross-sectional analysis of patients over 60 years of age with a presumptive diagnosis of iTTP between 2014 and 2022 at 10 centers. We calculated PLASMIC and French scores and compared our data with a single-center analysis of younger patients presenting with thrombotic microangiopathy. Results: Our study included 30 patients over 60 years of age and a control group of 28 patients younger than 60 years. The diagnostic sensitivity and specificity of a French score of ≥1 were lower in older patients compared to the control group (78.9% vs. 100% and 18.2% vs. 57.1%, respectively). The diagnostic sensitivity and specificity of a PLASMIC score of ≥5 were 100% vs. 95% and 27.3% vs. 100% for the study group and control group, respectively. Our study showed a higher mortality rate in older patients compared to the control group (30% vs. 7.1%, p=0.043). Conclusion: For a limited number of patients (n=6), our results showed that rituximab can reduce mortality. Given that the reliability of clinical prediction scores for iTTP in older patients may be lower, more caution must be undertaken in interpreting their results.