Glycosylated haemoglobin and relative polycythaemia in diabetes mellitus.

Sixty-five diabetic patients had a total red cell count significantly greater than 65 age and sex matched non-diabetics; (4.93 +/- 0.06 x 10(6) and 4.50 +/- 0.05 x 10(6) red cells/ul respectively; p less than 0.005). In 110 diabetic patients, total red cell count was positively correlated with the proportion of glycosylated haemoglobin (HbA1) (r = 0.32, p less than 0.001). The correlation was maintained in 60 of these patients with a mean blood glucose less than 15 mmol/l (r = 0.33, p less than 0.05), and in 49 non-smoking diabetic patients (r = 0.30, p = 0.05). It is proposed that the greater proportion of higher oxygen-affinity HbA1 in comparatively uncontrolled diabetics may be inducing sufficient tissue hypoxia to cause the demonstrated relative polycythaemia.