Validity of hemoglobin A1c for diagnosing diabetes among people with and without HIV in Uganda

Abstract

Sub-Saharan Africa (SSA) is facing a growing co-epidemic of chronic HIV infection and diabetes. Hemoglobin A1c (A1c) may underestimate glycemia among people living with HIV (PLWH). We estimated the validity of A1c to diagnose diabetes among PLWH and HIV-uninfected persons in rural Uganda. Data were derived from a cohort of PLWH and age- and gender-matched HIV-uninfected comparators. We compared A1c to fasting blood glucose (FBG) using Pearson correlations, regression models, and estimated the sensitivity and specificity of A1c for detecting diabetes with FBG ≥126 mg/dL as reference standard. Approximately half (48%) of the 212 participants were female, mean age of 51.7 years (SD = 7.0) at enrollment. All PLWH (n = 118) were on antiretroviral therapy for a median of 7.5 years with mean CD4 cell count of 442 cells/µL. Mean FBG (89.7 mg/dL) and A1c (5.6%) were not different between PLWH and HIV-uninfected ( P > 0.50) groups, but the HIV-uninfected group had a higher prevalence of A1c >5.7% (33% vs. 20%, P = 0.024). We found a relatively strong correlation between A1c and FBG (r = 0.67). An A1c ≥6.5% had a poor sensitivity (46%, 95% CI 26-67%) but high specificity (98%, 95% CI 96-99%) for detecting diabetes. More work is needed to define an optimal A1c for screening diabetes in SSA.