Concordance between fasting plasma glucose and HbA1c in the diagnosis of diabetes in black South African adults: a cross-sectional study

Clinical utility of glycated albumin and 1,5-anhydroglucitol in the screening and prediction of diabetes: A multi-center study

BACKGROUND

Despite being the gold standard, the use of glycated hemoglobin (HbA1c) and fasting plasma glucose (FPG) for diagnosing dysglycemia is imperfect. In particular, a low level of agreement between HbA1c and FPG in detecting prediabetes and diabetes has led to difficulties in clinical interpretation. Glycated albumin (GA) and 1,5-anhydroglucitol (1,5-AG) may potentially serve as biomarkers for the detection and prediction of diabetes, as well as glycemic monitoring.

AIM

To explore the diagnostic performance of GA and 1,5-AG for screening dysglycemia; assess whether they can be used for glycemic monitoring in Chinese morbidly-obese patients; and examine their predictive ability for incident diabetes in a Chinese community-based cohort.

METHODS

GA and 1,5-AG concentrations were measured in 462 morbidly-obese patients from the Obese Chinese Cohort (OCC). A sub-group of diabetes subjects (n = 24) was prospectively followed-up after bariatric surgery. Differences between baseline and post-surgery biomarker values were converted to percentage change from baseline to assess the response to glycemic control. Predictive ability of the biomarkers was assessed in 132 incident diabetes cases and 132 matched non-diabetes controls in the community-based Cardiovascular Risk Factor Prevalence Study (CRISPS). A prediction model was developed and compared with clinical models based on conventional risk factors.

RESULTS

GA exhibited an excellent diagnostic value with an area under the receiver operating characteristic curve (AUC) of 0.919 (95%CI: 0.884-0.955) for identifying diabetes and a high agreement in the classification of diabetes with both FPG and HbA1c in the OCC. GA demonstrated the fastest response to glycemic control. In CRISPS, the 'B3A' prediction model, which consisted of body mass index (BMI) and 3 biomarkers (HbA1c, GA and 1,5-AG), achieved a comparable predictive value [AUC (95%CI): 0.793 (0.744-0.843)] to that of a clinical model comprising BMI, HbA1c, FPG and 2-hour glucose (2hG) [AUC (95%CI): 0.783 (0.733-0.834); DeLong P value = 0.736]. The 'B3A' was significantly superior to a clinical model including BMI, HbA1c, FPG and triglycerides [AUC (95%CI): 0.729 (0.673-0.784); DeLong P value = 0.027].

CONCLUSION

GA and 1,5-AG have the potential to act as robust biomarkers for the screening and risk prediction of diabetes. FPG and 2hG may be replaced by GA and 1,5-AG in future diabetes predictions.

Incident type 2 diabetes and its risk factors in men and women aged 40-60 years from four sub-Saharan African countries: results from the AWI-Gen study

BACKGROUND

The incidence of type 2 diabetes in sub-Saharan Africa is expected to increase, but few longitudinal studies have characterised its risk factors. This study aimed to determine the incidence of type 2 diabetes over 33 481 person-years and identify its principal risk factors in middle-aged adults (ie, those aged 40-60 years) from four sub-Saharan African countries.

METHODS

Longitudinal data were available from 6553 participants aged 40-60 years at baseline from study centres in South Africa, Kenya, Ghana, and Burkina Faso. Sociodemographic, behavioural, clinical, and biochemical data were collected at baseline and after an interval of 5-6 years. The prevalence of type 2 diabetes was determined at each timepoint and diabetes incidence was calculated. A two-stage individual participant data meta-analysis was used to identify baseline risk factors for incident diabetes.

FINDINGS

The overall incidence of type 2 diabetes was 14·6 (95% CI 13·4-16·0) cases per 1000 person-years. The incidence was highest in South Africa with 21·8 (19·5-24·4) cases per 1000 person-years, and lowest in west Africa with 5·5 (4·4-6·9) cases per 1000 person-years. Baseline glucose (adjusted odds ratio 1·37; 95% CI 1·16-1·42), being male (1·32; 1·12-1·54), family history of type 2 diabetes (1·22; 1·01-1·46), unemployment (1·19; 1·03-1·37), hypertension (1·21; 1·01-1·45), BMI (1·03; 1·02-1·04), and waist circumference (1·02; 1·01-1·03), were associated with a higher risk of incident type 2 diabetes, while adequate baseline physical activity (0·87; 0·76-1·00) was associated with lower risk.

INTERPRETATION

The high incidence of type 2 diabetes in this middle-aged sub-Saharan Africa population is influenced by several modifiable risk factors that should inform interventions to mitigate the disease burden.

FUNDING

National Institutes of Health, Department of Science and Innovation (South Africa), and the South African Medical Research Council.

Advancing diabetes surveillance ecosystems: a case study of India

Professional society and expert guidelines recommend the achievement of glycaemic, blood pressure, and cholesterol targets to prevent the microvascular and macrovascular complications of diabetes. The WHO Diabetes Compact recommends that countries meet and monitor these targets for diabetes management. Surveillance-ie, continuous, systematic measurement, analysis, and interpretation of data-is a crucial component of public health. In this Personal View, we use the case of India as an illustration of the challenges and future directions needed for a diabetes surveillance system that documents national progress and persistent gaps. To address the growing burdens of diabetes and cardiometabolic diseases, the Government of India has launched programmes such as the National Programme for Prevention and Control of Non-Communicable Diseases. Different surveys have provided estimates of the diabetes care continuum of awareness, treatment, and control at the national, state, and, very recently, district level. We reviewed the literature to analyse how these surveys have varied in both their data collection methods and the reported estimates of the diabetes care continuum. We propose an integrated surveillance and monitoring framework to augment decentralised decision making, leveraging the complementary strengths of different surveys and electronic health record databases, such as data obtained by the National Programme for Prevention and Control of Non-Communicable Diseases, and building on methodological advances in model-based small-area estimation and data fusion. Such a framework could aid state and district administrators in monitoring the progress of diabetes screening and management initiatives, and benchmarking against national and global standards in all countries.

Global variation in diabetes diagnosis and prevalence based on fasting glucose and hemoglobin A1c

Fasting plasma glucose (FPG) and hemoglobin A1c (HbA1c) are both used to diagnose diabetes, but these measurements can identify different people as having diabetes. We used data from 117 population-based studies and quantified, in different world regions, the prevalence of diagnosed diabetes, and whether those who were previously undiagnosed and detected as having diabetes in survey screening, had elevated FPG, HbA1c or both. We developed prediction equations for estimating the probability that a person without previously diagnosed diabetes, and at a specific level of FPG, had elevated HbA1c, and vice versa. The age-standardized proportion of diabetes that was previously undiagnosed and detected in survey screening ranged from 30% in the high-income western region to 66% in south Asia. Among those with screen-detected diabetes with either test, the age-standardized proportion who had elevated levels of both FPG and HbA1c was 29-39% across regions; the remainder had discordant elevation of FPG or HbA1c. In most low- and middle-income regions, isolated elevated HbA1c was more common than isolated elevated FPG. In these regions, the use of FPG alone may delay diabetes diagnosis and underestimate diabetes prevalence. Our prediction equations help allocate finite resources for measuring HbA1c to reduce the global shortfall in diabetes diagnosis and surveillance.

Prevalence and correlates of pre-diabetes in Sub-Saharan Africa using Demographic and Health Survey Data: a cross-sectional study

OBJECTIVE

The objective is to investigate the prevalence of pre-diabetes in Namibia and South Africa and to determine sociodemographic correlates of disease using population data.

DESIGN

Cross-sectional study.

SETTING

Demographic and Health Survey for emerging (Namibia) and established (South Africa) economies in Sub-Saharan Africa collected laboratory data that allowed determination of pre-diabetes status.

PARTICIPANTS

3141 adults over age 18 from the 2013 Namibia survey, weighted to a population of 2176, and 4964 adults over age 18 from the 2016 South Africa survey, weighted to a population of 4627 had blood glucose/glycated haemoglobin (HbA1c) and diabetes information were included in the analysis.

OUTCOME MEASURES

Pre-diabetes was defined as not being diagnosed with diabetes and having a blood sugar measurement of 100-125 mg/dL in Namibia or an HbA1c measurement of 5.7%-6.4%. Logistic models were run for each country separately, with pre-diabetes as the outcome and a series of sociodemographic variables (age, gender, urban/rural residence, number of children, employment status, wealth index, education level, and ethnicity (in South Africa) or religion (in Namibia)) entered as variables to investigate the independent relationship of each.

RESULTS

The weighted prevalence of pre-diabetes was 18.7% in Namibia and 70.1% in South Africa. Rural residence was independently associated with higher odds of pre-diabetes in Namibia (1.47, 95% CI 1.05 to 2.06), while both younger age (0.98, 95% CI 0.97 to 0.99) and urban residence (0.80, 95% CI 0.66 to 0.99) were independently associated with odds of pre-diabetes in South Africa.

CONCLUSIONS

The prevalence of pre-diabetes was 18.7% in Namibia and 70.1% in South Africa. Correlates of pre-diabetes differed between the two countries with rural residents having higher odds of pre-diabetes in Namibia and urban residents with higher odds in South Africa. Aggressive interventions, including population level education and awareness programmes, and individual level education and lifestyle interventions that account for country-specific contextual factors are urgently needed to prevent progression to diabetes.

Diabetes care cascade and associated factors in 10 700 middle-aged adults in four sub-Saharan African countries: a cross-sectional study

OBJECTIVES

We investigated progression through the care cascade and associated factors for people with diabetes in sub-Saharan Africa to identify attrition stages that may be most appropriate for targeted intervention.

DESIGN

Cross-sectional study.

SETTING

Community-based study in four sub-Saharan African countries.

PARTICIPANTS

10 700 individuals, aged 40-60 years.

PRIMARY AND SECONDARY OUTCOME MEASURES

The primary outcome measure was the diabetes cascade of care defined as the age-adjusted diabetes prevalence (self-report of diabetes, fasting plasma glucose (FPG) ≥7 mmol/L or random plasma glucose ≥11.1 mmol/L) and proportions of those who reported awareness of having diabetes, ever having received treatment for diabetes and those who achieved glycaemic control (FPG <7.2 mmol/L). Secondary outcome measures were factors associated with having diabetes and being aware of the diagnosis.

RESULTS

Diabetes prevalence was 5.5% (95% CI 4.4% to 6.5%). Approximately half of those with diabetes were aware (54%; 95% CI 50% to 58%); 73% (95% CI 67% to 79%) of aware individuals reported ever having received treatment. However, only 38% (95% CI 30% to 46%) of those ever having received treatment were adequately controlled. Increasing age (OR 1.1; 95% CI 1.0 to 1.1), urban residence (OR 2.3; 95% CI 1.6 to 3.5), hypertension (OR 1.9; 95% CI 1.5 to 2.4), family history of diabetes (OR 3.9; 95% CI 3.0 to 5.1) and measures of central adiposity were associated with higher odds of having diabetes. Increasing age (OR 1.1; 95% CI 1.0 to 1.1), semi-rural residence (OR 2.5; 95% CI 1.1 to 5.7), secondary education (OR 2.4; 95% CI 1.2 to 4.9), hypertension (OR 1.6; 95% CI 1.0 to 2.4) and known HIV positivity (OR 2.3; 95% CI 1.2 to 4.4) were associated with greater likelihood of awareness of having diabetes.

CONCLUSIONS

There is attrition at each stage of the diabetes care cascade in sub-Saharan Africa. Public health strategies should target improving diagnosis in high-risk individuals and intensifying therapy in individuals treated for diabetes.

The triglyceride glucose-waist-to-height ratio outperforms obesity and other triglyceride-related parameters in detecting prediabetes in normal-weight Qatari adults: A cross-sectional study

INTRODUCTION

The triglyceride-glucose (TyG)-driven indices, incorporating obesity indices, have been proposed as reliable markers of insulin resistance and related comorbidities such as diabetes. This study evaluated the effectiveness of these indices in detecting prediabetes in normal-weight individuals from a Middle Eastern population.

METHODS

Using the data of 5,996 adult Qatari participants from the Qatar Biobank cohort, we employed adjusted logistic regression to assess the ability of various obesity and triglyceride-related indices to detect prediabetes in normal-weight (18.5 ≤ BMI <25 kg/m2) adults (≥18 years).

RESULTS

Of the normal-weight adults, 13.62% had prediabetes. TyG-waist-to-height ratio (TyG-WHTR) was significantly associated with prediabetes among normal-weight men [OR per 1-SD 2.68; 95% CI (1.67-4.32)] and women [OR per 1-SD 2.82; 95% CI (1.61-4.94)]. Compared with other indices, TyG-WHTR had the highest area under the curve (AUC) value for prediabetes in men [AUC: 0.76, 95% CI (0.70-0.81)] and women [AUC: 0.73, 95% CI (0.66-0.80)], and performed significantly higher than other indices (p < 0.05) in detecting prediabetes in men. Tyg-WHTR shared similar diagnostic values as fasting plasma glucose (FPG).

DISCUSSION

Our findings suggest that the TyG-WHTR index could be a better indicator of prediabetes for general clinical usage in normal weight Qatari adult men than other obesity and TyG-related indices. TyG-WHTR can help identify a person's risk for developing prediabetes in both men and women when combined with FPG results.

Waist circumference thresholds predicting incident dysglycaemia and type 2 diabetes in Black African men and women

AIMS

To determine the waist circumference (WC) thresholds for the prediction of incident dysglycaemia and type 2 diabetes (T2D) in Black South African (SA) men and women and to compare these to the advocated International Diabetes Federation (IDF) Europid thresholds.

MATERIALS AND METHODS

In this prospective study, Black SA men (n = 502) and women (n = 527) from the Middle-aged Sowetan Cohort study who had normal or impaired fasting glucose at baseline (2011-2015) were followed up until 2017 to 2018. Baseline measurements included anthropometry, blood pressure and fasting glucose, HDL cholesterol and triglyceride concentrations. At follow-up, glucose tolerance was assessed using an oral glucose tolerance test. The Youden index was used to determine the optimal threshold of WC to predict incident dysglycaemia and T2D.

RESULTS

In men, the optimal WC threshold was 96.8 cm for both dysglycaemia and T2D (sensitivity: 56% and 70%; specificity: 74% and 70%, respectively), and had higher specificity (P < 0.001) than the IDF threshold of 94 cm. In women, the optimal WC threshold for incident dysglycaemia was 91.8 cm (sensitivity 86%, specificity 37%) and for T2D it was 95.8 cm (sensitivity 85%, specificity 45%), which had lower sensitivity, but higher specificity to predict incident dysglycaemia and T2D than the IDF threshold of 80 cm (sensitivity: 97% and 100%; specificity: 12% and 11%, respectively)).

CONCLUSIONS

We show for the first time using prospective cohort data from Africa that the IDF Europid WC thresholds are not appropriate for an African population, and show that African-specific WC thresholds perform better than the IDF Europid thresholds to predict incident dysglycaemia and T2D.

Echocardiographic and Electrocardiographic Abnormalities Among Elderly Adults With Cardiovascular Disease in Rural South Africa

BACKGROUND

Sub-Saharan Africa is undergoing an epidemiological transition fueled by the interaction between infectious and cardiovascular diseases. Our cross-sectional study aimed to characterize the spectrum of abnormalities suggesting end-organ damage on ECG and transthoracic echocardiograms (TTE) among older adults with cardiovascular diseases in rural South Africa.

METHODS

The prevalence of ECG and TTE abnormalities was estimated; χ2 analyses and multivariable logistic regressions were performed to test their association with sex, hypertension, and other selected comorbidities.

RESULTS

Overall, 729 ECGs and 155 TTEs were completed, with 74 participants completing both. ECG evaluation showed high rates of left ventricular hypertrophy (LVH, 36.5%) and T wave abnormalities (13.6%). TTE evaluation showed high rates of concentric LVH (31.6%), with moderate-severe (56.8%) diastolic dysfunction. Participants with hypertension showed more cardiac remodeling on ECG by LVH (45.4% versus 22.1%, P<0.01), and TTE by concentric LVH (42.5% versus 8.2%, P<0.01) and increased left ventricular mass (58.5% versus 20.4%, P<0.0001). In multivariable logistic regression, systolic blood pressure remained significantly associated with LVH on ECG (adjusted odds ratio, 1.03 per mm Hg [95% CI, 1.03-1.04], P<0.0001) and increased left ventricular mass on TTE (adjusted odds ratio, 1.04 per mm Hg [95% CI, 1.01-1.06], P=0.001). Male participants (n=326, 40.2%) were more likely than females (n=484, 59.8%) to show ECG abnormalities like LVH (45% versus 30.8%, P<0.01), whereas females were more likely to show TTE abnormalities like concentric LVH (40.8% versus 13.5%, P<0.01) and increased left ventricular mass (58.4% versus 23.1%, P<0.0001). Similar results were confirmed in multivariable models.

CONCLUSIONS

Our findings suggest that cardiovascular diseases are widespread in rural South Africa, with a larger burden of hypertensive heart disease than previously appreciated, and define the severity of end-organ damage that is already underway. Local health systems must adapt to face the growing burden of hypertension, as suboptimal rates of hypertension diagnosis and treatment may dramatically increase the heart failure burden.