Prospective analysis of newly diagnosed autoimmune hemolytic anemia: A single center study

Background: Autoimmune hemolytic anemia (AIHA) is an autoimmune- mediated disease in which erythrocytes are destroyed through (auto)antibodies against their surface antigens, resulting in premature lysis. It is a rare disorder and data about characteristics of AIHA from clinical practice are rare, especially if collected prospectively. Aims: This prospective study was conducted in order to analyze characteristics of patients with newly diagnosed AIHA. Methods: A single-center prospective study was performed at the University Hospital Center Zagreb (UHC), a tertiary center and the largest Croatian hospital, which included all consecutive patients with a newly diagnosed direct antiglobulin test positive AIHA from 1st Jan 2019 to 31th Dec 2020. Study was approved by UHC Ethical Committee. Descriptive statistics were performed and results are reported as frequencies (percentage) for categorical and as means (±standard deviation) or medians (minimum-maximum), as appropriate, for continuous values. Results: Data includes 17 patients (41% men), median age at diagnosis 52 (5-76) years. Majority of patients had secondary AIHA (14/17, 82%), mostly due to underlying lymphoproliferative malignant disease (7/14 patients, 50%). 4 had underlying autoimmune disorders, 1 solid cancer, 1 developed AIHA after allogeneic bone marrow transplantation, and 1 after M. pneumoniae infection. Median hemoglobin (Hb) at diagnosis was 74 (39-124) g/L;12 (71%) patients required hospital care with admission Hb of 58 (39-124) g/L, and 10 (59%) received erythrocyte transfusion. 15 (88%) patients required therapy with corticosteroids, and 6 (35%) received rituximab (as the first line therapy in 3/6 (50%) of patients). Patients were followed with a median time of 474 (22-648) days during which 13 (76%) achieved complete remission (CR) without signs of hemolysis or anemia, 1 showed improvement but failed to achieve normal Hb levels, 1 was refractory to therapy, and 2 were lost to follow-up. Median time from diagnosis to best response was 137 (43- 606) days. Of 13 patients in CR, 2 (15%) relapsed which was observed 260 and 363 days after remission. During follow up 2 patients suffered from COVID-19 infection, but neither showed signs of AIHA relapse. 2 patients died during follow-up due to AIHA-unrelated causes. Summary/Conclusion: Although with relatively small number of patients, this prospective study of newly diagnosed AIHA patients showed increased percentage of rituximab administration (from 17.6% to 35%) comparing to our previous retrospective single-center analysis from 2014 to 2018 (EHA library: Pulanic D, et al. 2019;PB 1963.). This is probably due to the increase of rituximab availability due to lower costs and more experience with this treatment modality.