Homocysteine has associations with both vitamin insufficiency and vascular complications, and its status is therefore of interest in sickle cell disease (SCD). However, information is limited, especially in adults. We studied plasma total homocysteine (tHcy) and three of its major modifiers, cobalamin, folate, and creatinine, in 90 adult patients with SCD and 76 control subjects. The patients had higher tHcy levels than did controls (P = 0.03) and had elevated tHcy more often (20% vs. 3%, P = 0.0005). None of the hyperhomocysteinemic patients had low cobalamin or folate levels; on the contrary, patients with SCD had high folate levels more often than control subjects (32% vs. 7%; P < 0.0001). Although serum creatinine values were lower in SCD patients than in control subjects (P = 0.03), high levels also tended to occur more often (8% vs. 1%; P = 0.054). Most importantly, creatinine levels correlated significantly with tHcy (P < 0.0001) and logistic regression analyses showed creatinine to be the only significant predictor of high tHcy levels in SCD (P = 0.01). Our results show that hyperhomocysteinemia affects 20% of adults with SCD despite routine folate supplementation and is independent of folate and cobalamin status. Creatinine was the major identifiable influence on tHcy, but renal insufficiency explained only 4 of the 18 elevated tHcy levels. Longitudinal studies will be needed to determine whether the frequent hyperhomocysteinemia of SCD influences the vascular complications in SCD. If reducing tHcy becomes advisable, then interventions other than folate therapy will be needed.
Copyright 2004 Wiley-Liss, Inc.