Glycated albumin and fructosamine do not improve accuracy of glycaemic control assessment in patients with conditions reported to affect HbA1c reliability.

Aims: HbA_1c testing in African populations may be limited due to high prevalence of hemoglobinopathies, anaemia, malaria and renal impairment. We aimed to assess the performance of glycated albumin (GA) and fructosamine in comparison to HbA_1c for determining glycaemic control in Africans living with type 2 diabetes.

Methods: We compared the relationship between fructosamine, GA, and HbA_1c with mean continuous glucose monitoring (CGM) glucose and assessed the impact of sickle cell trait (SCT), anaemia and renal impairment on the relationship between each measure and CGM glucose.

Results: The overall association of HbA_1c, GA and fructosamine with CGM glucose was similar (r = 0.88 [95%CI: 0.84, 0.91], 0.84 [0.79, 0.88] and 0.84 [0.79, 0.88]), respectively. For detecting those with mean CGM glucose >8 mmol/L HbA_1c had similar diagnostic accuracy to GA and fructosamine, even in those with conditions reported to affect HbA_1c performance (n = 63). We found no evidence that SCT (n = 43/192) altered the relationship between HbA_1c, fructosamine or GA with CGM glucose (p > 0.3 for all). However, individuals with anaemia showed an underestimation of CGM glucose by HbA_1c and fructosamine compared to those without anaemia (p for interaction <0.005 for both). In contrast, GA with average CGM glucose between those with anaemia and those without were not significantly different.

Conclusions: Switching to fructosamine or GA is unlikely to improve the accuracy of laboratory glycaemic monitoring beyond that of HbA_1c in a population with high prevalence of conditions reported to affect HbA_1c reliability.