Mean Red Blood Cell Volume, Narcotic Addiction, and Glucose Tolerance

To the Editor.  —Increased mean red cell volume (RCV) in alcoholic subjects receiving methadone has been reported by Stimmel et al.¹ They suggested that although the specificity of RCV may be helpful in eliminating those persons who are not actively alcoholic, its sensitivity does not permit its use as a biologic marker for alcoholism in addicts. On the other hand, prior publications suggest that sensitivity of the mean red blood cell volume to detect alcoholism may be variable.^2,3 Impaired glucose tolerance has occurred in opiate addicts by altered glucose utilization^4,5 and by increased glycosylated hemoglobin (Hb A₁)⁶ and glycosylated proteins.⁷Moreover, we reported hematologic alterations in opiate addicts⁸ similar to those found in diabetics.^9,10 Since increased RCV in diabetes mellitus correlated with metabolic control has been reported,¹¹ we investigated RCV and glycosylated Hb A₁, which represents a useful index of glucose tolerance,¹² in 50 male opiate addicts (age,