Plasma glucose reference intervalin a low-risk population. 2. Impact ofthe new WHO and ADA recommendations on the diagnosis of diabetes mellitus

Abstract

Theaim ofthe studywas to establish a referenceintervaloffasting venous plasma glucose (FPG) from healthy individuals. A prospective modified cross-sectional population-based study was made with random selection of 2100 persons in agestratified groups 18 years identified from the local Personal Identification Register. The invitation was accepted by 755 persons, of which 726 aged 18-92 years were eligible. They did not have a diabetes diagnosis, were non-pregnant and capable offasting for 8h. Allparticipants filled in a questionnaireon medical risk factors. Blood for the FPG and haemoglobin A1c (HbA1c) measurements was drawn in accordance with a standardized procedure. A total of 302 participants carried diabetes risk indicators and wereruled out.TheFPG concentrations in the remaining low-risk population (n=424) was ln Gaussian distributed. The FPG 97.50 centile in this group was 6.4mmol/L (95% CI: 6.3-6.5mmol/L), in contrast to the WHO and ADA theoretical limit of 6.1mmol/L. Their diagnostic decision limit of 7.0mmol/L FPG corresponded to the 99.86 centile of the FPG reference distribution (95% CI: 6.8-7.1). Subclassification of the reference population showed increasing FPG with increasing BMI and age and was higher in men than in women. The study determined the FPG 95% interfractile reference interval in a healthy population. The interval in glucose concentration between the 97.5 centile of the reference interval and the ADA-WHO diagnostic limit is very narrow. The clinical application of the diagnostic discriminator and the interpretation of the WHO-ADA grey zone from 6.1 to 7.0mmol/L FPG may consequently be biased because of poorly defined limits and influence from BMI, age and gender.

• Words Ada Recommendations Diabetes Mellitus Fpg Reference Interval Plasma Glucose Concentration Who Guidelines