IDF2022-0761 Discrepancy between interstitial glucose and HbA1c in people with HIV compared to people without HIV in a Zambian cohort

Diabetes is reported to be more common in people living with HIV (PLWH). There is not an internationally agreed screening method for diabetes in PLWH due to reports that HbA1c is falsely low in this group. Continuous glucose monitoring (CGM) has been used to explore HbA1c and glucose discrepancy. Its role in identification of dysglycaemia in PLWH is not known and data from Southern Africa are scarce. To explore the relationship between HbA1c and interstitial glucose, including discrepancy between these markers of glycaemia, in a cohort of people without diabetes by HIV serostatus in Lusaka, Zambia. Participants were purposefully recruited from a clinic in Lusaka, Zambia as part of a nested study within a larger cohort study. CGM, Dexcom G6, were worn for up to 10 days and HbA1c measured. Bland Altman plot was used to assess the agreement between HbA1c and a CGM derived surrogate HbA1c termed ‘glucose management indicator’ (GMI) presenting the mean difference as bias. This was performed in people with HIV on anti-retroviral treatment ≥6 months and without HIV. Mann Whitney U test was performed to assess the difference in bias between groups. 21 PLWH (67% female, mean age (±SD) 39 years (±9), mean HbA1c 35.5 [±4.3] mmol/mol, mean Hb 13.1 [±2.1] g/dL, mean MCV 91.7 [±8.7] fl) and 30 people without HIV (70% female, mean age 40 [±10], mean HbA1c 37.5 [±5.2] mmol/mol, mean Hb 13.6 [±1.9] g/dL, mean MCV 85.5 [±9.2] fl) were recruited. Bland-Altman plot demonstrates the bias between the two methods in PLWH was –5.9 mmol/mol (95% limits of agreement –16.4–+4.6) and without HIV –5.5 mmol/mol (95% limits of agreement –13.4–+2.3), p = 0.9. Figure 1 displays HbA1c plotted against mean sensor glucose with the reference line used to generate GMI. In this small Zambian cohort, there is little difference in agreement between interstitial glucose and HbA1c in PLWH and people without HIV. GMI appears to overestimate HbA1c. Larger controlled studies with additional markers of glycaemia are needed to explore HbA1c discrepancy in PLWH and to define the role of CGM in PLWH.