Clinical Characteristics and Long Term Outcomes of Warm Type Autoimmune Hemolytic Anemia

Back ground

Warm type autoimmune hemolytic anemia (AIHA) is the disease which antibody reacts with self-antigen on red blood cell. Due to the uncommon of this disease, there is a little data about long term outcomes and response to therapy especially second line treatment.

Methods

This is a retrospective single center study from 2002 to 2013. The diagnosis of AIHA was made by positive direct Coombs’ test with clinical hemolysis and confirmed by Hematologist. Clinical data and long term outcome were reviewed and analyzed.

Results

During that period, 101 patients were reviewed, 77% were female, median age was 43 (15-83) years. The median hemoglobin level at diagnosis was 5.4 (2-10) g/dl. Primary AIHA was found in 61%. The secondary causes were SLE (64%), solid malignancy (13%), lymphoma (10%), drug (8%) and infection (5%). The secondary cause from SLE was commonly found in female (96%) (P<0.001). There was the difference of age between secondary cause from SLE (<50 years) and malignancy (>50 years) (p=0.013). These results showed the interesting data that secondary cause of AIHA needed to be searching especially SLE in young female and secondary cancer in elderly patients. Not only cause could be identified but also the specific treatment needed to be given according to secondary cause.

Interestingly, most patients (96%) were initially response to steroid which was not different between primary and secondary AIHA. Second line treatments were required in 33 patients (33%). The indications were steroid dependent (58%), relapse (30%) and others (12%). The second line treatments were including cyclophosphamide (52%), azathioprine (21%), cyclosporine (6%), splenectomy (6%), danazol (6%) and others (9%). The overall response rate for second line was 93%. SLE group received second line therapy more than non SLE group (p<0.001). In the light of data from this study showed that this disease had a good prognosis in both frontline steroid and second line treatment. Relapse was occurred in 50 patients (50%). Most relapse occurred > 3 years after diagnosis (58%) and more common in SLE group (p<0.001). These findings illustrated the importance nature of the disease that need long follow up due to high relapse rate around half of patients.

At the median follow up 53 months, the overall survival (OS) and event free survival (relapse and death) were 84% and 48%, respectively. The independent factor for decreasing OS was age >50 years with HR 3.09 (95% CI 1.09-8.73, p=0.03) and malignancy with HR 4.06 (95% CI 1.18-13.97, p=0.03). The only significant factor for relapse is age >50 years with HR 2.08 (95% CI 1.21-3.57, p = 0.008). Twenty patients were death. The common cause of death was sepsis (30%) due to heavily immunosuppressive treatment.

Conclusion

AIHA has good prognosis and long term survival especially in young patient without secondary malignancy. The search for secondary cause especially malignancy is important. Most patients have responded initially to steroid and high response rate to second line therapy. The most common cause of death was sepsis which related to treatment side effect. Carefully adjust and rapid taper immunosuppressant is considerable to avoid serious complication.

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