OBJECTIVES: Acquired Thrombotic Thrombocytopenic Purpura (aTTP) is an ultra-rare, life-threatening blood clotting disorder manifested by microvascular occlusions and consequent thrombocytopenia, hemolytic anemia, organ ischemia and potentially premature death. We assessed, through the French medico-administrative national hospital discharge database (PMSI), the number of patients hospitalized with an aTTP episode and their characteristics, management patterns, main disorders and mortality during the stay.

METHODS: Patients hospitalized between 2012 and 2014 with a first diagnosis of an aTTP episode were identified. A backward algorithm was designed starting from M31.1-Thrombotic microangiopathy (TMA) ICD-10 code, including aTTP diagnoses, then excluding other TMA’s (hereditary TTP, haemolytic-uremic syndrome) and selecting acute episodes (ICU admission, ≥ 1 plasma exchange [PEX]).

RESULTS: Over the 3-year study, of 1,476 patients with TMA diagnosis, 229 had other TMA than aTTP, 893 had no criteria for an acute episode and 6 had a history of aTTP. Thus, 348 patients with a first aTTP episode were identified. The mean age was 48.8 years [SD: 17.5] and male/female ratio was 1:2. The median length of first aTTP stay was 20.0 days [Q1-Q3: 13-32], including 8 days [Q1-Q3: 5-14] in the ICU. During the stay, patients underwent a median number of 7.0 PEX [Q1-Q3: 3-12]. Moreover, 50 patients (14.4%) had at least one event of interest: 3 patients experienced splenectomy, 11 an infectious disease, 17 a nervous system disorder, 2 a major thromboembolic event, 4 a cardiac disorder, and 19 an acute renal failure. Lastly, 53 (15.2%) patients died during the stay.

CONCLUSIONS: These findings from patients with aTTP in-hospital diagnosis, admitted in ICU and who benefited from PEX, confirm the high morbidity and mortality related to aTTP episodes reported in literature (Benhamou, 2012), despite the currently available therapies. Relapse rate, long-term consequences and economic burden of aTTP are being assessed through an ongoing longitudinal follow-up study.