Priscila Aparecida Correa Freitas

Factors affecting A1C in non-diabetic individuals: Review and meta-analysis.

We carried out a systematic review and meta-analyses of studies that evaluated the possible effects of anemia, variant hemoglobin, and uremia on A1C levels in individuals without diabetes (DM). Medline and Embase were searched for studies that measured A1C values in groups with and without iron deficiency anemia (IDA) and/or iron deficiency (ID), variant hemoglobin and/or uremia by standardized methods. The difference between A1C levels in the groups with and without interferences was obtained by using random-effects meta-analysis and the effect size was presented as absolute difference of means (95% CI). Ten studies fulfilled the inclusion criteria, providing data from 11,176 participants without DM. There were no statistically significant differences in A1C in the presence of IDA/ID, HbS, and uremia by HPLC and uremia by immunoassay [0.79% (95% IC -0.39; 1.97), -0.13% (95% IC -0.51; 0.26), 0.15% (95% CI -0.58; 0.88) and -0.19% (95% CI -0.78; 0.40), respectively]. The effects of HbAS and uremia on A1C levels are within the expected individual variation and should not affect A1C results to diagnose DM. However, the effects of IDA/ID remain inconclusive and further studies are needed to clarify the glycation mechanisms in individuals with IDA/ID without diabetes.

Effect of ethnicity on HbA1c levels in individuals without diabetes: Systematic review and meta-analysis

Aims/Hypothesis Disparities in HbA1c levels have been observed among ethnic groups. Most studies were performed in patients with diabetes mellitus (DM), which may interfere with results due to the high variability of glucose levels. We conducted a systematic review and meta-analysis to investigate the effect of ethnicity on HbA1c levels in individuals without DM. Methods This is a systematic review with meta-analysis. We searched MEDLINE and EMBASE up to September 2016. Studies published after 1996, performed in adults without DM, reporting HbA1c results measured by certified/standardized methods were included. A random effects model was used and the effect size was presented as weighted HbA1c mean difference (95% CI) between different ethnicities as compared to White ethnicity. Results Twelve studies met the inclusion criteria, totalling data from 49,238 individuals. There were significant differences between HbA1c levels in Blacks [0.26% (2.8 mmol/mol); 95% CI 0.18 to 0.33 (2.0 to 3.6), p <0.001; I2 = 90%, p <0.001], Asians [0.24% (2.6 mmol/mol); 95% CI 0.16 to 0.33 (1.7 to 3.6), p <0.001; I2 = 80%, p = 0.0006] and Latinos [0.08% (0.9 mmol/mol); IC 95% 0.06 to 0.10 (0.7 to 1.1); p <0.001; I2 = 0%; p = 0.72] when compared to Whites. Conclusions/Interpretation This meta-analysis shows that, in individuals without DM, HbA1c values are higher in Blacks, Asians, and Latinos when compared to White persons. Although small, these differences might have impact on the use of a sole HbA1c point to diagnose DM in all ethnic populations.

Glycated albumin: a potential biomarker in diabetes

Diabetes mellitus (DM) is a chronic and metabolic disease that presents a high global incidence. Glycated hemoglobin (A1C) is the reference test for long-term glucose monitoring, and it exhibits an association with diabetic chronic complications. However, A1C is not recommended in clinical situations which may interfere with the metabolism of hemoglobin, such as in hemolytic, secondary or iron deficiency anemia, hemoglobinopathies, pregnancy, and uremia. The glycated albumin (GA) is a test that reflects short-term glycemia and is not influenced by situations that falsely alter A1C levels. GA is the higher glycated portion of fructosamine. It is measured by a standardized enzymatic methodology, easy and fast to perform. These laboratory characteristics have ensured the highlight of GA in studies from the last decade, as a marker of monitoring and screening for DM, as well as a predictor of long-term outcomes of the disease. The aim of this review was to discuss the physiological and biochemistry characteristics of the GA, as well as its clinical utility in DM.

Comparison between two enzymatic methods for glycated albumin

Glycated albumin (GA) has attracted considerable interest as an alternative laboratory marker for glycated haemoglobin (A1C). GA reflects a short-term glucose monitoring, and it is not influenced by haemoglobin metabolism. Recently, there have been reports of new enzymatic methodologies for GA measurement. The aim of this study was to perform a comparison between two GA enzymatic assays commercially available in Brazil (Crystal Chem® and Diazyme®) with samples from adult patients with and without diabetes (N = 85), following CLSI recommendations. For the study, we assessed the diabetic status of patients according to their A1C levels, and we excluded those with clinical conditions that could interfere with GA or A1C levels. We observed a very strong and significant correlation (R = 0.91, p < 0.001) between the methods. The Bland–Altman plot showed a good overall agreement between the GA results (1.2% ± 2.45%; mean of absolute differences ± SD), and the Passing–Bablok regression indicated no differences between the assays. The Diazyme® GA kit presented a lower analytical imprecision (CV% inter = 8.7%) than Crystal Chem® (CV% inter = 10.0%). GA and A1C showed a moderate correlation when measured by the Diazyme® or Crystal Chem® kits (R = 0.71 and R = 0.63; p < 0.001, respectively). To the best of our knowledge, this is the first study to evaluate the Crystal Chem® kit. Diazyme® and Crystal Chem® GA assays showed a good correlation with a small difference. The association between GA and A1C demonstrates that this new marker may be a useful alternative when A1C results are unreliable.

Are A1C levels at the moment of DM diagnosis associated with renal outcomes

Materials and methods This prospective study evaluated 269 patients screened to DM type 2 at a university hospital between 2008 and 2009. All patients performed an oral glucose tolerance test (OGTT), fasting glucose (FG), urinary albumin and A1C measured by colorimetry, immunoturbidimetry (Advia 1800, Siemens Diagnostica) and HPLC (2.2 Tosoh Plus A1C, Tosoh Corporation), respectively. They were identified with DM according to ADA criteria. Between 2010 and 2012, the patients returned and were re-evaluated. Renal outcomes were measured by urinary albumin levels in the follow up, according with KDIGO guidelines. Poisson regression with robust standard errors was performed in those with DM diagnosis, considering the worsening of renal function, measured by urinary albumin levels, as dependent variable and A1C, FG, 2h plasma glucose after OGTT (G2h) levels, age and hypertension as independent variables. Statistical analysis was performed by SPSS 20.0 and p 0.05). Only age was risk factor (p <0.001; relative risk 1.074 [1.0351.114] to the worsening of renal function, where the increase of one year in age was associated with 7.4% increase in the risk to renal outcomes.

Older patients are at increased risk for renal posttransplantation diabetes mellitus.

Materials and methods All patients without diabetes who underwent renal transplant at a University Hospital between July 2012 and June 2015 were included. PTDM was diagnosed according to current ADA criteria at four months after transplantation. Poisson regression with robust standard errors was performed with PTDM as dependent variable and the possible risk factors under study (age, sex, type of donor, immunosuppressive type, family history of DM, pre-transplant BMI and fasting plasma glucose) as independent variables. P-value <0.05 was considered as statistically significant.