Alpha-thalassemia is associated with a decreased occurrence and a delayed age-at-onset of albuminuria in sickle cell anemia patients.

The aim of this study was to identify possible risk factors for albuminuria, an early marker of sickle cell anemia (SCA) glomerulopathy, in a cohort of 189 SCA adult patients followed at the Sickle Cell Center of Guadeloupe, a French Caribbean island. Biological parameters obtained at baseline, alpha-globin gene status, and beta(S) haplotypes were compared in patients stratified accordingly to graded albuminuria. Abnormal albumin excretion rate was detected in half of the studied adult patients and macroalbuminuria occurred in 21.6%. Graded albuminuria was associated with advanced age (p=0.006), systolic blood pressure (p=0.031), and worsened anemia, i.e. low hemoglobin rate (p<0.0001) and red blood cell count (p<0.0001). Alpha-thalassemia frequency was lower in microalbuminuric and macroalbuminuric patients than in normoalbuminuric patients, 12.5%, 13.75% and 26%, respectively (p=0.0057). Comparison of albuminuria-free survival curves in SCA patients without and with alpha-thalassemia showed that the median time of albuminuria onset was delayed in the later ones (p=0.021). In contrast, no association of albuminuria was detected with the Bantou beta(S) haplotype. Our results strongly suggest a protective effect of alpha-thalassemia against glomerulopathy in SCA adult patients which could be related to a decreased hemolytic rate. 2010 Elsevier Inc. All rights reserved.