Longitudinal changes in serum fructosamine do not parallel those in glycated haemoglobin in young adults with insulin-dependent diabetes.

In 93 adolescent and young adult patients with type 1 diabetes (163 paired comparisons) changes in fructosamine concentration correlated poorly with changes in HbA1 (r = 0.53); this correlation was no better if fructosamine values were adjusted for serum albumin by calculating a fructosamine/albumin index, F.A.I. (155 pairs, r = 0.50). These correlation coefficients were lower than those for cross-sectional comparisons (HbA1 vs. fructosamine, r = 0.74; HbA1 vs. F.A.I., r = 0.80). One-way analysis of variance showed that values of HbA1, fructosamine and F.A.I. all tended to increase as glycaemic control, judged by the clinician, worsened (P less than 0.001). HbA1 correlated better with clinical assessment than did either uncorrected fructosamine or F.A.I. We conclude that changes in fructosamine from one clinic visit to the next do not provide a basis for changing therapy. Clinical assessments tend to agree with values for HbA1, which may be more reliable than fructosamine because of its longer biological half life.