Using haemoglobin A(1c) to diagnose type 2 diabetes or to identify people at high risk of diabetes

Effect of hemoglobin A1c management levels on coronary physiology evaluated by quantitative flow ratio in patients who underwent percutaneous coronary intervention

AIMS/INTRODUCTION

The coronary physiology and prognosis of patients with different hemoglobin A1c (HbA1c) levels after percutaneous coronary intervention (PCI) are currently unknown. The aim of this study was to assess the effect of different levels of HbA1c control on coronary physiology in patients who underwent PCI for coronary heart disease combined with type 2 diabetes mellitus by quantitative flow ratio (QFR).

MATERIALS AND METHODS

Patients who successfully underwent PCI and completed 1-year coronary angiographic follow up were enrolled, clinical data were collected, and QFR at immediate and 1-year follow up after PCI was retrospectively analyzed. A total of 257 patients (361 vessels) were finally enrolled and divided into the hemoglobin A1c (HbA1c)-compliance group (103 patients, 138 vessels) and non-HbA1c-compliance group (154 patients, 223 vessels) according to the HbA1c cut-off value of 7%. We compared the results of QFR analysis and clinical outcomes between the two groups.

RESULTS

At 1-year follow up after PCI, the QFR was significantly higher (0.94 ± 0.07 vs 0.92 ± 0.10, P = 0.019) and declined less (0.014 ± 0.066 vs 0.033 ± 0.095, P = 0.029) in the HbA1c-compliance group. Meanwhile, the incidence of physiological restenosis was lower in the HbA1c-compliance group (2.9% vs 8.5%, P = 0.034). Additionally, the target vessel revascularization rate was lower in the HbA1c-compliance group (6.8% vs 16.9%, P = 0.018). Furthermore, HbA1c ≥7% (OR 2.113, 95% confidence interval 1.081-4.128, P = 0.029) and QFR decline (OR 2.215, 95% confidence interval 1.147-4.277, P = 0.018) were independent risk factors for target vessel revascularization.

CONCLUSION

Patients with well-controlled HbA1c levels have better coronary physiological benefits and the incidence of adverse clinical outcome events might be reduced.

Assessment of glycaemic status in adult hospital patients for the detection of undiagnosed diabetes mellitus: A systematic review

AIM

In-hospital blood glucose testing is commonplace, particularly in acute care. In-hospital screening for hyperglycaemia may present a valuable opportunity for early diabetes diagnosis by identifying at-risk individuals. This systematic review investigates the extent to which random blood glucose testing in acute and inpatient hospital settings predicts undiagnosed diabetes.

METHODS

Two databases were systematically searched for studies in which adult patients received an in-hospital random blood glucose test, followed by a diagnostic HbA1c test. The primary outcome was the proportion of hyperglycaemic individuals diagnosed with diabetes by HbA1c.

RESULTS

A total of 3245 unique citations were identified, and 12 were eligible for inclusion. Ten different blood glucose thresholds, ranging from 5.5 to 11.1 mmol/L, were used to detect hyperglycaemia, indicating that there is no consistent clinical definition for hyperglycaemia. The proportion of participants with hyperglycaemia in each study ranged from 3.3% to 62.1%, with a median (Q₁ , Q₃ ) of 34.5% (5.95%, 61.1%). The proportion of hyperglycaemic participants found to have a diabetes-range HbA1c varied from 4.1% to 90%, with a median (Q₁ , Q₃ ) of 18.9% (11.5%, 61.1%). Meta-analysis was not possible due to substantial heterogeneity between study protocols.

CONCLUSIONS

All studies consistently identified a proportion of hyperglycaemic hospital patients as having a diabetes-range HbA1c, showing that in-hospital blood glucose screening can facilitate diabetes diagnosis. The proportion of hyperglycaemic participants with undiagnosed diabetes varied substantially, indicating a need for further research and consistency in defining in-hospital hyperglycaemia. This may aid the development of a standardised screening protocol to identify people with possible undiagnosed diabetes.

Choice of HbA1c threshold for identifying individuals at high risk of type 2 diabetes and implications for diabetes prevention programmes: a cohort study

BACKGROUND

Type 2 diabetes (T2D) is common and increasing in prevalence. It is possible to prevent or delay T2D using lifestyle intervention programmes. Entry to these programmes is usually determined by a measure of glycaemia in the 'intermediate' range. This paper investigated the relationship between HbA1c and future diabetes risk and determined the impact of varying thresholds to identify those at high risk of developing T2D.

METHODS

We studied 4227 participants without diabetes aged ≥ 40 years recruited to the Exeter 10,000 population cohort in South West England. HbA1c was measured at study recruitment with repeat HbA1c available as part of usual care. Absolute risk of developing diabetes within 5 years, defined by HbA1c ≥ 48 mmol/mol (6.5%), according to baseline HbA1c, was assessed by a flexible parametric survival model.

RESULTS

The overall absolute 5-year risk (95% CI) of developing T2D in the cohort was 4.2% (3.6, 4.8%). This rose to 7.1% (6.1, 8.2%) in the 56% (n = 2358/4224) of participants classified 'high-risk' with HbA1c ≥ 39 mmol/mol (5.7%; ADA criteria). Under IEC criteria, HbA1c ≥ 42 mmol/mol (6.0%), 22% (n = 929/4277) of the cohort was classified high-risk with 5-year risk 14.9% (12.6, 17.2%). Those with the highest HbA1c values (44-47 mmol/mol [6.2-6.4%]) had much higher 5-year risk, 26.4% (22.0, 30.5%) compared with 2.1% (1.5, 2.6%) for 39-41 mmol/mol (5.7-5.9%) and 7.0% (5.4, 8.6%) for 42-43 mmol/mol (6.0-6.1%). Changing the entry criterion to prevention programmes from 39 to 42 mmol/mol (5.7-6.0%) reduced the proportion classified high-risk by 61%, and increased the positive predictive value (PPV) from 5.8 to 12.4% with negligible impact on the negative predictive value (NPV), 99.6% to 99.1%. Increasing the threshold further, to 44 mmol/mol (6.2%), reduced those classified high-risk by 59%, and markedly increased the PPV from 12.4 to 23.2% and had little impact on the NPV (99.1% to 98.5%).

CONCLUSIONS

A large proportion of people are identified as high-risk using current thresholds. Increasing the risk threshold markedly reduces the number of people that would be classified as high-risk and entered into prevention programmes, although this must be balanced against cases missed. Raising the entry threshold would allow limited intervention opportunities to be focused on those most likely to develop T2D.

The substantial burden of non-communicable diseases and HIV-comorbidity amongst adults: Screening results from an integrated HIV testing services clinic for adults in Soweto, South Africa

BACKGROUND

South Africa is disproportionately impacted by non-communicable diseases (NCDs) and HIV/AIDS. We investigated the prevalence of known/unknown NCD risk factors, HIV, and NCD risk factor-HIV comorbidity; and treatment status on known diseases to determine the prevalence of controlled/uncontrolled disease.

METHODS

This cross-sectional study (June 2018-March 2019) within an integrated testing centre in Soweto, South Africa, screened adults (aged ≥18 years) for body mass index (BMI), hypertension (HT), rapid glucose and cholesterol, and HIV. Results were stratified by age group, sex, HIV-status, and self-reported ART use. Analysis included Fisher's exact, chi-squared, Kruskal Wallis, and Student's T-tests.

FINDINGS

Of 780 enrolled participants, 19.2% were HIV-positive, 37.5% were overweight/obese, 18.0% hypertensive, 10.8% hyperglycaemic, and 8.1% had hypercholesterolaemia. Significantly more women had overweight/obese BMI than men (46.8% vs 19.7%; p<0.0001), and women aged 25-34 years had significantly more hypercholesterolaemia than same-aged men (18.2% vs 5.6%; p = 0.02). HIV-positive participants had significantly more hyperglycaemia than HIV-negative participants (16.1% vs 9.6%; p = 0.02), and those on ART (63.9%) had significantly more hypercholesterolaemia than those not on ART (21.7% vs. 4.9%; p = 0.002). Of participants with HT, hyperglycaemia, and hypercholesterolaemia; 72.4%, 96.1%, and 93.3% were newly diagnosed. All participants with previously diagnosed NCDs remained with uncontrolled disease.

INTERPRETATION

There is a high burden of HIV, NCD risk factors, and comorbidity in Soweto, and amongst young adults (18-34 years), especially women. Lowering age requirements for glucose/cholesterol screening to 18+ years, regardless of BMI, HIV-status, or ART use, may yield timely NCD diagnosis/management.

Health screening, cardiometabolic disease and adverse health outcomes in individuals with severe mental illness

BACKGROUND

Poor physical health in severe mental illness (SMI) remains a major issue for clinical practice.

AIMS

To use electronic health records of routinely collected clinical data to determine levels of screening for cardiometabolic disease and adverse health outcomes in a large sample (n = 7718) of patients with SMI, predominantly schizophrenia and bipolar disorder.

METHOD

We linked data from the Glasgow Psychosis Clinical Information System (PsyCIS) to morbidity records, routine blood results and prescribing data.

RESULTS

There was no record of routine blood monitoring during the preceding 2 years for 16.9% of the cohort. However, monitoring was poorer for male patients, younger patients aged 16-44, those with schizophrenia, and for tests of cholesterol, triglyceride and glycosylated haemoglobin. We estimated that 8.0% of participants had diabetes and that lipids levels, and use of lipid-lowering medication, was generally high.

CONCLUSIONS

Electronic record linkage identified poor health screening and adverse health outcomes in this vulnerable patient group. This approach can inform the design of future interventions and health policy.

Prevalence and Associated Risk Factors of Diabetes in the African Immigrant Population of Sacramento County, California

Purpose

The purpose of this study was to determine the prevalence and associated risk factors of diabetes in the African immigrant population in Sacramento County, California.

Methods

A cross-sectional study was conducted in Sacramento County, California, from June to August 2018. The convenience sample included 126 African immigrants aged 21 years and older. Sociodemographic and clinical characteristics were collected. Hemoglobin A1C (A1C) level, blood pressure, height, and weight were measured per standard methods. Data were analyzed using descriptive statistics and χ2 test at value of P < .05.

Results

Of 126 adult individuals included in this study, 32 (25.4%) had diabetes, of whom 25 (19.8%) were previously diagnosed and 7 (5.6%) represented new cases of diabetes. Also, 36 (28.6%) had prediabetes, of whom 24 (19.1%) had previously been told they had prediabetes and 12 (9.5%) represented new cases of prediabetes. Diabetes and prediabetes were significantly higher among participants in the age group of 36 to 60 years, married, employed full-time, and those with hypertension, high blood cholesterol, and participating in 0 to 2 days per week of moderate physical activities. Only one-fifth of all participants with previously known diabetes or previously on treatment had a good glycemic control status.

Conclusions

The present study found a high prevalence of prediabetes, diabetes, and multiple risk factors of diabetes in the African immigrant population, as well as a poor glycemic control among those with diabetes, calling for urgent attention. Strategies aimed to improving a healthy lifestyle in the African immigrant population are necessary to reduce the burden of diabetes.

HbA1c: a review of non-glycaemic variables

Identification of the correlation between HbA1c and diabetic complications has yielded one of the most clinically useful biomarkers. HbA1c has revolutionised the diagnosis and monitoring of diabetes mellitus. However, with widespread adoption of HbA1c has come increasing recognition that non-glycaemic variables can also affect HbA1c, with varying clinical significance. Furthermore, the identification of a discrepancy between predicted and measured HbA1c in some individuals, the so-called 'glycation gap', may be clinically significant. We aimed to review the current body of evidence relating to non-glycaemic variables to quantify any significance and provide subsequent suggestions. A PubMed-based literature search was performed, using a variety of search terms, to retrieve articles detailing the non-glycaemic variables suggested to affect HbA1c. Articles were reviewed to assess the relevance of any findings in clinical practice and where possible guidance is given. A range of non-glycaemic variables have statistically significant effects on HbA1c. While the clinical implications are generally irrelevant, a small number of non-glycaemic variables do have clinically significant effects and alternative biomarkers should be considered instead of, or in addition to, HbA1c. There are a small number of non-glycaemic variables which have a clinically significant effect on HbA1c, However, the vast majority of non-glycaemic variables have no clinical relevance. While clinicians should have an awareness of those non-glycaemic variables with clinical significance, in the vast majority of clinical scenarios HbA1c should continue to be used with confidence.

Monitoring HIV-infected Patients with Diabetes: Hemoglobin A1c, Fructosamine, or Glucose?

BACKGROUND

Published studies report inappropriately low hemoglobin A1C (HbA1c) values that underestimate glycemia in HIV patients.

METHODS

We reviewed the charts of all HIV patients with diabetes mellitus (DM) at our clinic. Fifty-nine patients had HbA1c data, of whom 26 patients also had fructosamine data. We compared the most recent HbA1c to finger-stick (FS) glucose averaged over three months, and fructosamine to FS averaged over six weeks. Predicted average glucose (pAG) was calculated as reported by Nathan et al: pAG (mg/dL) = 28.7 × A1C% − 46.7. Data were analyzed using the Statistical Analysis System (SAS) and Kruskal–Wallis test.

RESULTS

HbA1c values underestimated (UE) actual average glucose (aAG) in 19% of these patients and overestimated (OE) aAG in 27%. HbA1c estimated aAG within the established range in only 54% of the patients. There were no statistical differences in the types of HIV medication used in patients with UE, OE, or accurately estimated (AE) glycemia. A Spearman correlation coefficient between HbA1c and aAG was r = 0.53 (P < 0.0001). Correlation between fructosamine and aAG was r = 0.47 (P = 0.016).

CONCLUSIONS

The correlations between HbA1c and aAG and between fructosamine and aAG were weaker than expected, and fructosamine was not more accurate than HbA1c.