Danielle A.J.M. Schoenaker, Dominique Simon, Nish Chaturvedi et al. Journal of Clinical Endocrinology & Metabolism. Doi: 10.1210/jc.2013-2824
The appropriate target for HbA1c in type 2 diabetes has been debated for some time. The assumption has remained, however, that tight control in type 1 diabetes (T1DM) remains a legitimate goal and so this publication, suggesting otherwise, is provocative. The authors analysed 2,764 patients with T1DM, enrolled in the EURODIAB Prospective Complications Study. They report that HbA1c was related to all-cause mortality in a non-linear manner after adjustment for age and sex. All-cause mortality risk was increased at both low (5.6%) and high (11.8%) HbA1c compared to the reference (median HbA1c: 8.1%) creating a U-shaped association, as has been reported in T2DM. Leaving aside any suspicions of statistical ‘adjustments’, and the possibility of confounders such as anaemia, renal insufficiency and infection (highlighted by the authors), this paper provides a rider, which will be useful in clinical practice. For many (perhaps most) patients with T1DM, achievement of tight HbA1c targets is incompatible with normal life and certainly driving. To have a lower limit, beyond which harm rather than benefit increases, will be reassuring to patients and take some of the pressure off clinicians.