The relationship between glycated haemoglobin levels and the risk of giant cell arteritis - a case-control study.

HbA1c in the diabetic range reduces the probability of GCA. HbA1c should be considered in any multivariable score to calculate the risk of GCA, and in future development of diagnostic and classification criteria. There is a need for an epidemiological study looking at the possibility of a protective nature of diabetes mellitus against GCA or whether it is only a mimic.