A1C underestimates glycemia in HIV infection

Glycated haemoglobin in diabetic women with and without HIV infection: data from the Women's Interagency HIV Study

BACKGROUND

Limited data suggest that glycated haemoglobin (haemoglobin A1c; A1C) values might not reflect glycaemic control accurately in HIV-infected individuals with diabetes.

METHODS

We evaluated repeated measures of paired fasting glucose and A1C values in 315 HIV-infected and 109 HIV-uninfected diabetic participants in the Women's Interagency HIV Study. Generalized estimating equations used log A1C as the outcome variable, with adjustment for log fasting glucose concentration in all models.

RESULTS

An HIV-infected woman on average had 0.9868 times as much A1C (that is, 1.32% lower; 95% confidence interval 0.9734-0.9904) as an HIV-uninfected woman with the same log fasting glucose concentration. In multivariate analyses, HIV serostatus was not associated, but White, other non-Black race, and higher red blood cell mean corpuscular volume (MCV) were statistically associated with lower A1C values. Use of diabetic medication was associated with higher A1C values. In multivariate analyses restricted to HIV-infected women, White and other race, higher MCV, and HCV viraemia were associated with lower A1C values, whereas older age, use of diabetic medications and higher CD4(+) T-cell count were associated with higher A1C values. Use of combination antiretroviral therapy, protease inhibitors, zidovudine, stavudine or abacavir was not associated with A1C values.

CONCLUSIONS

A1C values were modestly lower in HIV-infected diabetic women relative to HIV-uninfected diabetic women after adjustment for fasting glucose concentration. The difference was abrogated by adjustment for MCV, race and diabetic medication use. Our data suggest that in clinical practice A1C gives a reasonably accurate refection of glycaemic control in HIV-infected diabetic women.

The impact of sickle cell trait on glycated haemoglobin in diabetes mellitus

AIMS

To determine the effect of sickle cell trait on measurement of glycated haemoglobin (HbA(1c)) in African American patients with diabetes mellitus.

METHODS

This is a retrospective study including 885 outpatients who underwent HbA(1c) testing. Medical record review and sickle cell trait determinations based on the HbA(1c) assay were performed in African American participants. The relationship between HbA(1c) and serum glucose measurements was analysed.

RESULTS

Data were obtained from 385 AA (109 with SCT, 22 with haemoglobin C trait and 254 without haemoglobinopathy) and 500 European American patients. In a model created through multivariate repeated-effects regression, the relationship between HbA(1c) and simultaneous serum glucose did not differ between African American subjects with and without the sickle cell trait, but differed between African American subjects without the sickle cell trait and European Americans (P = 0.0002).

CONCLUSIONS

Sickle cell trait does not impact the relationship between HbA(1c) and serum glucose concentration. In addition, it does not appear to account for ethnic difference in this relationship between African Americans and whites.

The effects of intermittent, CD4-guided antiretroviral therapy on body composition and metabolic parameters

OBJECTIVE

To assess the effects of decreased antiretroviral therapy exposure on body fat and metabolic parameters.

DESIGN

Substudy of the Strategies for Management of Anti-Retroviral Therapy study, in which participants were randomized to intermittent CD4-guided [Drug Conservation (DC) group] or to continuous [Viral Suppression (VS) group] antiretroviral therapy.

METHODS

Participants at 33 sites were coenrolled in the Strategies for Management of Anti-Retroviral Therapy Body Composition substudy. Regional fat was assessed annually by whole-body dual-energy X-ray absorptiometry and abdominal computed tomography. Fasting metabolic parameters were assessed at months 4, 8, and annually. Treatment groups were compared for changes in fat and metabolic markers using longitudinal mixed models.

RESULTS

Two hundred and seventy-five patients were randomized to the DC (n = 142) or VS (n = 133) group and followed for a median of 2.0 years. By month 12, limb fat (DC-VS difference 9.8%, 95% confidence interval 3.5-16.1; P = 0.003) and subcutaneous abdominal fat (DC-VS difference 14.3 cm, 95% confidence interval -0.1 to 28.7; P = 0.05) increased in the DC group. There was no treatment difference in visceral abdominal fat (DC-VS difference -2.1%, 95% confidence interval -13.5 to 9.4; P = 0.72). Lipids significantly decreased in the DC group by month 4 and treatment differences persisted throughout follow-up (P < or = 0.001). By 12 months, hemoglobin A1C increased in the DC (+0.3%) and remained stable in the VS group (P = 0.003); the treatment difference remained significant throughout follow-up (P = 0.02).

CONCLUSION

After 12 months, intermittent antiretroviral therapy increased subcutaneous fat, had no effect on visceral abdominal fat, decreased plasma lipids, and increased hemoglobin A1C compared with continuous antiretroviral therapy.