Centralised versus local measurement of glycated haemoglobin in clinical trial settings: a comment on Arch et al., Trials. 2016.

Arch and colleagues in their 24 October 2016 paper in Trials focus on the issue of centralised versus local measurement of glycated haemoglobin (HbA1c) in clinical trial settings. Resolution of the debate is important: while local HbA1c measurement is less costly, and would thereby ease the stretched funding situations for clinical trials worldwide, it cannot be implemented at the expense of clinically unacceptable disparities between centralised and localised measurements. Arch and colleagues favour centralised measurement in their paper's conclusion. However, critical questions regarding the methods require a closer look. In this letter, we discuss some of the issues that the authors could clarify in order that the reader can agree (or disagree) to their inference with greater confidence.