Can continuous glucose monitoring be used as a new tool for diagnosing white coat hyperglycaemia and possibly some other entities?

Abstract

Introduction. Since 1999 continuous glucose monitoring (CGM) has been used to measure the amount of glucose in the interstitial fluid. CGM is crucial when it comes to developing the ambulatory glucose profile and giving information on time spent in range (TIR), percentage of time spent above and below range, as well as variability. Discussion. It was in 1992 that Campbell et al. first described white coat hyperglycaemia, who explained it as patients having elevated blood glucose levels in a clinician's office or laboratory and normal glucose levels obtained by self-monitoring. Prior to the introduction of CGM, white coat hyperglycaemia was described as the discrepancy in the levels of office glucose and self-monitoring blood glucose (SMBG). Nowadays, it may be said that a patient has white coat hyperglycaemia when they have elevated office levels and normal SMBG levels or TIR above 70% on CGM. Recognising white coat hyperglycaemia is of crucial importance for treatment as its intensification based on office glycaemia alone can lead to episodes of hypoglycaemia and a potentially lethal outcome. Should comparison be made with arterial hypertension and ambulatory blood pressure monitoring (ABPM), CGM may provide several other options: 1) masked hyperglycaemia; 2) isolated nocturnal hyperglycaemia. Conclusion. It seems logical that CGM can be used for diagnosing white coat hyperglycaemia and possibly some (new) entities. Nonetheless, the clinical significance of all these entities can only be discussed after conducting adequately designed randomised clinical trials, which we would strongly encourage.