East meditteranean region sickle cell disease mortality study: A multicentric retrospective cohort study of 735 patients

Sickle cell disease is one of the most common genetic disorders worldwide characterized by chronic hemolytic anemia and tissue injury. A number of study showed that addition of hydroxyurea is essential for the prevention of tissue damage in patients with sickle cell disease. In contrast, only sparce data exist about its affect on prolongation of life expectancy. Despite the presence of the studies investigating causes of mortality, age of mortality, distribution of mortality rates according to years in sickle cell disease patients, data are not avaliable in literature about the factors affecting mortality and comparison of surviving–dying patiens. We aimed to investigate the ages and causes of deaths from sickle cell disease in a large population of children and adults living in the Mediterranean region of Turkey and to determine factors associated with death. In this multicentric retrospective cohort study conducted between 2005-2015, data were collected from 102 children and 633 adults with sickle cell disease. Among the 735 cases, 67 % were homozygous hemoglobin S (Hb S) disease, 17 % Hb S-β0 thalassemia, 15% Hb S-β+ thalassemia and 1 % Hb S-α thalassemia. Forty four (6 %) patients were recorded to die from adults while 1 child (0,1 %) died. Median age at death was 34,1± 10 (18- 54) years for males, 40.1± 15 (17- 64) years for females, 36,6± 13 years (17- 64) for both. Overall, 25 % patients were considered to have frequent painful crisis (>3 per year) and no effect on mortality. On univariate analysis, death was found to be associated with acute chest syndrome, hypertension, renal disease and not use of hydroxyurea (p= 0.007, p= 0.015, p= 0.000, p= 0.009 respectively). Also on univariate analysis, death was found to be associated with higher leukocyte, platelet and lower hemoglobine count (p= 0.000, p= 0.000, p= 0.000 respectively). On multivariate analysis death was found to be associated with only higher leukocyte count (p= 0.009). In this large study of 735 cases of sickle cell disease, main causes of death included complications of disease such as acute chest syndrome, splenic sequestration, and prolonged painful crisis leading to multi-organ failure. Comorbid conditions such as hypertension and renal failure were considered as major risks for mortality which should help to optimize the therapeutic management. We may conclude that the results of this study could help the clinicians to make a decision for the time of application of a curative treatment alternative.