Is There a Discrepancy between Interstitial Glucose and Laboratory HbA1c in People Living with HIV?

Background: Diabetes is reported to be more common in people living with HIV (PLWH) . There is no internationally agreed screening method for diabetes in PLWH due to reports that HbA1c is falsely low in this group. The ADA recommend a fasting glucose to screen for diabetes in PLWH whilst the British HIV Association recommend measuring HbA1c. Aims: To explore the relationship between HbA1c and interstitial glucose in PLWH. Methods Each participant wore a Dexcom G6 for days and had HbA1c measured. Exclusion criteria included factors affecting HbA1c. HbA1c values were compared to GMI values. Bland-Altman plot method was used to assess the agreement between the measurements. Results: We included 57 PLWH (27 with T2DM, 6 female) , median HbA1c 44mmol/mol (IQR 38-55) , average sensor glucose 7.3mmol/l (IQR 6.4-9.1) . Median completed CGM readings per participant 99% (IQR 92-99) . Bland-Altman plot method (see figure) demonstrates the bias between the two methods is -3.2mmol/mol (95% CI: -1.0 to -5.6) with 95% limits of agreement -14.2 to 20.6. Six participants had an HbA1c 10mmol/mol lower than GMI and 2 had an HbA1c 10mmol/mol higher. Conclusion: This is the first study using CGM to explore HbA1c discrepancy in PLWH. It shows the bias between interstitial glucose and HbA1c is small with moderate agreement between the two methods. Our data support a potential role for using HbA1c to assess glycaemia in PLWH. Disclosure H. Daultrey: None. N. Oliver: Advisory Panel; Dexcom, Inc., Medtronic, Roche Diabetes Care. Research Support; Dexcom, Inc., Medtronic. A. Chakera: None. Funding Dexcom - providing the glucose monitors for the study.