Eculizumab is effective in managing patients with
paroxysmal nocturnal hemoglobinuria (PNH). In South Korea, the financial support for
eculizumab therapy is extended by the National Health Insurance Services (NHIS) only to patients with high-risk PNH for approximately 10 years. In this study, we performed a nationwide analysis of the real-world efficacy of
eculizumab therapy in patients diagnosed with PNH between January 1, 2002, and December 31, 2016, by using the NHIS database. Patients treated with
eculizumab (the
eculizumab-treated group) exhibited a significantly higher survival rate than patients not treated with
eculizumab (the
eculizumab-untreated group), with 4-year survival rates after propensity score matching of 98.31% and 79.67%, respectively (p = 0.0489). The mean red blood cell (RBC) transfusion units per 12 months after
eculizumab therapy were significantly lower than that before
eculizumab therapy (5.75 units vs. 12.28 units, p < 0.0001). The median time for the first transfusion in the
eculizumab-treated group was significantly longer than that in the
eculizumab-untreated group. The 4-year transfusion-independence rate for the
eculizumab-treated group was significantly higher than that for the
eculizumab-untreated group (20.81% vs. 10.24%, p = 0.078). There was no significant difference between the two groups in the incidence of new documented complications related to PNH. In conclusion,
eculizumab therapy for patients with high-risk PNH may effectively improve the survival rate and reduce the transfusion requirement. Paradoxically,
eculizumab-treated patients with severe PNH exhibit a higher survival rate than
eculizumab-untreated patients with less severe PNH.