Does increased red blood cell deformability raise the risk for osteonecrosis in sickle cell anemia?

摘要

The pathogenesis of osteonecrosis in sickle cell anemia (SCA) remains unknown. Blood hyperviscosity has been suggested as a factor involved in the genesis of osteonecrosis,1 but has not been studied until now. We hypothesized that abnormal hemorheo-logy could play a role in this complication. Hematologic and hemorheologic parameters were assessed in SCA patients with (OST+; n = 30) or without (OST-; n = 67) osteonecrosis. Osteonecrosis was diagnosed as previously described.2 The study was conducted according to the Declaration of Helsinki guidelines and was approved by the Regional Ethics Committee. The results are reported in Table 1. OST+ patients were older than OST— patients (P < .05) and more had a history of vaso-occlusive crises (VOC) within the previous year (P < .05) and a higher frequency of a-thalassemia (P < .05), confirming previous studies.3"5 Although the OST+ group exhibited higher hemoglobin (Hb) and hematocrit and a lower hemolytic component than the OST— group (P < .01), blood viscosity was not significantly different between the 2 groups (P < .20). In contrast, red blood cell (RBC) deformability (P < .001) and aggregation (P < .05) were increased in the OST+ group.