About 7% of the adult population has subclinical cobalamin (B12) deficiency and it is a significant health problem, particularly among the 35 million elderly in the United States, 15% of whom have the deficiency. Its prevalence in sickle cell disease (SCD) is not known. Al-Momen reports low vitamin cobalamin levels in 43.5% of patients with SCD in Saudi Arabia. Dhar et al. recently described a sickle cell patient with pernicious anemia and reviewed two additional cases from the literature. This is a retrospective study in which we compared the clinical and laboratory characteristics of low serum cobalamin in patients with SCD to those in African-American patients without this hemoglobinopathy (non-SCD).
Institutional review board approval was obtained and medical records were reviewed. Between 1993 and 2003, 105 SCD and 112 non-SCD patients who had serum cobalamin levels done because of anemia were identified at Howard University Hospital. The diagnosis in the SCD patients was documented by hemoglobin (Hb) electrophoresis. For the purposes of this study, non-SCD patients were considered so because of their older age without any history, symptoms or laboratory findings suggestive of hemoglobinopathy. In the sickle cell patients, cobalamin levels were obtained for various reasons, such as a high red-cell mean corpuscular volume (MCV) and unexplained worsening of their anemia. Our laboratory used the solid-phase no boil (DUAL count) radioas-say method initially followed by competitive immunoassay for the past few years to measure cobalamin levels. The normal range for serum cobalamin values at our hospital is 200-950 pg/ml. Medical records were reviewed for demographics. For our study purposes, a low cobalamin level was defined by a serum В12 lower than 200 pg/ml. We defined pernicious anemia by a low B12 level, along with a positive serum intrinsic factor antibody, a high serum gastrin or an abnormal Schilling’s test. For statistical signifi cance determinations, we used Chi-squared tests for categorical variables and t tests for continuous variables. In nine of the non-SCD patients, the chart designated the cobalamin value only as “normal.” In these cases we arbitrarily used 250 pg/ml as the missing value in the statistical calculations. When you can’t afford your medication buy online generic rosiglitazone