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Reduced sensitivity of PLASMIC and French scores for the diagnosis of thrombotic thrombocytopenic purpura in older individuals
Author(s) -
Liu Angela,
Dhaliwal Noor,
Upreti Harshvardhan,
Kasmani Jamil,
Dane Kathryn,
Moliterno Alison,
Braunstein Evan,
Brodsky Robert,
Chaturvedi Shruti
Publication year - 2021
Publication title -
transfusion
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.045
H-Index - 132
eISSN - 1537-2995
pISSN - 0041-1132
DOI - 10.1111/trf.16188
Subject(s) - medicine , thrombotic thrombocytopenic purpura , confidence interval , thrombotic microangiopathy , creatinine , gastroenterology , platelet , microangiopathy , schistocyte , microangiopathic hemolytic anemia , pediatrics , surgery , endocrinology , diabetes mellitus , disease
Background Thrombotic thrombocytopenic purpura (TTP) is a life‐threatening disorder characterized by thrombocytopenia, microangiopathic hemolysis, and ischemic organ failure. The PLASMIC and French TTP scores can help guide clinical decisions when ADAMTS13 testing is not immediately available. Older individuals often present atypically, but the impact of age on these tools is not known. Study Design and Methods We calculated the sensitivity and specificity of the PLASMIC and French TTP scores in patients enrolled in the Johns Hopkins thrombotic microangiopathy (TMA) registry. Results Of 257 patients with TMA enrolled in the registry, we excluded patients less than 18 years of age (n = 19), with prior TMA (n = 81) or who initially presented at another hospital (n = 25). The remaining 132 patients (75 with TTP and 57 with other TMA) were analyzed. Sensitivity of a French score of 2 decreased with age and was 72.2%, 61.5%, and 46.2% for ages 18 to 39, 40 to 59, and ≥ 60 years old, respectively. A PLASMIC score ≥ 5 had higher sensitivity than the French score but this also decreased with age; sensitivity was 91.4% (95% confidence interval [CI], 76.9‐98.2), 78.3% (95% CI, 56.3‐92.5), and 76.9% (95% CI, 46.2‐95.0) for patients 18 to 39, 40 to 59, and ≥ 60 years old, respectively. Older patients had higher platelet counts and serum creatinine than the youngest group, contributing to the loss in sensitivity. Conclusion The PLASMIC and French TTP scores have reduced sensitivity at age ≥ 60 years and are less reliable in identifying TTP in older patients. A high index of suspicion and availability of rapid ADAMTS13 assays is required to correctly diagnose all patients with TTP.