Burden of Diabetes and First Evidence for the Utility of HbA1c for Diagnosis and Detection of Diabetes in Urban Black South Africans: The Durban Diabetes Study

The association between body weight indices, behavioral factors, and type 2 diabetes mellitus in Africa: A systematic review and meta-analysis of population-based epidemiological studies

BACKGROUND AND AIM

Type 2 diabetes mellitus (T2DM) is a significant public health concern in Africa. While the associations between modifiable risk factors and T2DM are likely to be Africa-specific, their overall estimations have not been published. This study aimed to use systematic and meta-analytic methods to examine the strength of associations between modifiable risk factors and T2DM in Africa.

METHODS AND RESULTS

A systematic search of literature published between January 2000 to March 2022 was conducted. The review included only population-based studies and data extracted from 57 studies. Of these, unadjusted data from 50 studies were included in meta-analysis. With considerable heterogeneity between studies, random-effect models were calculated to ascertain the odds ratios (OR) and 95% confidence intervals (CI) for the associations between obesity (OB) and overweight (OV), defined by BMI; central obesity (waist circumference (OB-WC), waist-to-hip-ratio (OB-WHR)), alcohol, fruit and vegetable consumption, smoking, physical activity (PA) and T2DM. Moderator effects of age, African regions, and urban/rural location were assessed. Risk factors associated with T2DM include BMI-OB [OR = 3.05, 95% CI: (2.58, 3.61)], BMI-OV [OR = 2.38, 95% CI: (1.51, 3.75)], and BMI-OV/OB [OR = 2.07, 95% CI: (1.82, 2.34)]; OB-WC [OR = 2.58, 95% CI: (2.09, 3.18)] and OB-WHR [OR = 2.22, 95% CI: (1.69, 2.92)]; PA [OR = 1.85, 95% CI: (1.50, 2.30)]. Significant moderator effects were not observed.

CONCLUSION

Obesity defined by BMI and central obesity, but not behavioral risk factors were most strongly associated with T2DM in African populations, emphasizing the need for obesity prevention to limit the rise of T2DM.

REGISTRATION

The PROSPERO registration number is CRD42016043027.

Uncovering myocardial infarction genetic signatures using GWAS exploration in Saudi and European cohorts

Genome-wide association studies (GWAS) have yielded significant insights into the genetic architecture of myocardial infarction (MI), although studies in non-European populations are still lacking. Saudi Arabian cohorts offer an opportunity to discover novel genetic variants impacting disease risk due to a high rate of consanguinity. Genome-wide genotyping (GWG), imputation and GWAS followed by meta-analysis were performed based on two independent Saudi Arabian studies comprising 3950 MI patients and 2324 non-MI controls. Meta-analyses were then performed with these two Saudi MI studies and the CardioGRAMplusC4D and UK BioBank GWAS as controls. Meta-analyses of the two Saudi MI studies resulted in 17 SNPs with genome-wide significance. Meta-analyses of all 4 studies revealed 66 loci with genome-wide significance levels of p < 5 × 10-8. All of these variants, except rs2764203, have previously been reported as MI-associated loci or to have high linkage disequilibrium with known loci. One SNP association in Shisa family member 5 (SHISA5) (rs11707229) was evident at a much higher frequency in the Saudi MI populations (> 12% MAF). In conclusion, our results replicated many MI associations, whereas in Saudi-only GWAS (meta-analyses), several new loci were implicated that require future validation and functional analyses.

Pregnancy and diabetic ketoacidosis: fetal jeopardy and windows of opportunity

Background

Diabetic ketoacidosis (DKA) during pregnancy poses significant risks to both the mother and fetus, with an increased risk of fetal demise. Although more prevalent in women with Type I diabetes (T1D); those with Type 2 diabetes (T2D) and gestational diabetes mellitus (GDM) can also develop DKA. A lack of information about DKA during pregnancy exists worldwide, including in South Africa.

Objective

This study examined the characteristics and outcomes associated with DKA during pregnancy.

Methods

The study took place between 1 April 2020 and 1 October 2022. Pregnant women with DKA, admitted to Tygerberg Hospital's Obstetric Critical Care Unit (OCCU) were included. Maternal characteristics, precipitants of DKA, adverse events during treatment, and maternal-fetal outcomes were examined.

Results

There were 54 episodes of DKA among 47 women. Most DKA's were mild and occurred in the third trimester. Pregestational diabetes dominated (31/47; 60%), with 47% having T1D and 94% requiring insulin. Seven women (7/47, 15%; T2D:6, T1D:1) had two episodes of DKA during the same pregnancy. Most women (32/47; 68%) were either overweight or obese. Yet, despite the T2D phenotype, biomarkers indicated that auto-immune diabetes was prevalent among women without any prior history of T1D (6/21; 29%). Twelve women (26%) developed gestational hypertension during pregnancy, and 17 (36%) pre-eclampsia. Precipitating causes of DKA included infection (14/54; 26%), insulin disruption (14/54; 26%) and betamethasone administration (10/54; 19%). More than half of the episodes of DKA involved hypokalemia (35/54, 65%) that was associated with fetal death (P=0.042) and hypoglycemia (28/54, 52%). Preterm birth (<37 weeks' gestation) occurred in 85% of women. No maternal deaths were recorded. A high fetal mortality rate (13/47; 28%) that included 11 spontaneous intrauterine deaths and two medical terminations, was observed.

Conclusion

Women with DKA have a high risk of fetal mortality as well as undiagnosed auto-immune diabetes. There is a strong link between maternal hypokalemia and fetal loss, suggesting an opportunity to address management gaps in pregnant women with DKA.

Identification and characterisation of diabetes in Uganda: protocol for the nested, population-based 'Diabetes in low-resource Populations' (DOP) Study

INTRODUCTION

Sub-Saharan Africa is experiencing an increasing burden of diabetes, but there are little reliable data, particularly at the community level, on the true prevalence or why this condition affects young and relatively lean individuals. Moreover, the detection of diabetes in Africa remains poor, not only due to a lack of resources but because the performance of available diagnostic tests is unclear.

METHODS

This research aims to (1) determine the prevalence and risk factors of diabetes in a rural Ugandan population, (2) use clinical and biochemical markers to define different diabetes phenotypes and (3) study the progression of diabetes in this population. We will also assess the utility of the widely used tests (glycated haemoglobin (HbA1c), oral glucose tolerance test (OGTT) and fasting glucose) in diagnosing diabetes.

DESIGN

This is a population-based study nested within the longstanding general population cohort in southwestern Uganda. We will undertake a population survey to identify individuals with diabetes based on fasting glucose, HbA1c, OGTT results or history of pre-existing diabetes.

PARTICIPANTS

The study intends to enrol up to 11 700 individuals aged 18 years and above, residing within the study area and not pregnant or within 6 months post-delivery date. All participants will have detailed biophysical and biochemical/metabolic measurements. Individuals identified to have diabetes and a random selection of controls will have repeat tests to test reproducibility before referral and enrolment into a diabetic clinic. Participants will then be followed up for 1 year to assess the course of the disease, including response to therapy and diabetes-related complications.

CONCLUSIONS

These data will improve our understanding of the burden of diabetes in Uganda, the risk factors that drive it and underlying pathophysiological mechanisms, as well as better ways to detect this condition. This will inform new approaches to improve the prevention and management of diabetes.

ETHICS AND DISSEMINATION

This study protocol was approved by the Uganda Virus Research Institute Research Ethics Committee (REC) (number: G.C./127/21/09/858), the London School of Hygiene and Tropical Medicine REC (number: 26638) and the Uganda National Council for Science and Technology (protocol number: HS1791ES). Written informed consent will be obtained from all participants before being enrolled on to the study and conducting study-related procedures. Research findings will be disseminated in policy briefs, seminars, local and international conferences and publications in peer-reviewed open-access journals. As part of the dissemination plans, findings will also be disseminated to patient care groups and to clinicians.

TRIAL REGISTRATION NUMBER

NCT05487079.

Early postpartum HbA1c after hyperglycemia first detected in pregnancy-Imperfect but not without value

BACKGROUND

South African women of childbearing age are disproportionally affected by obesity and at significant risk of Type 2 Diabetes Mellitus (T2DM). Unless pregnant, they do not readily undergo screening for T2DM. With a local focus on improved antenatal care, hyperglycemia is often first detected in pregnancy (HFDP). This may erroneously be attributed to Gestational Diabetes Mellitus (GDM) in all without considering T2DM. Glucose evaluation following pregnancy is essential for early detection and management of women with T2DM in whom persistent hyperglycemia is to be expected. Conventional testing with an oral glucose tolerance test (OGTT) is cumbersome, prompting investigation for alternate solutions.

AIM

To compare the diagnostic performance of HbA1c to the current gold standard OGTT in women with HFDP 4-12 weeks post-delivery.

METHODS

Glucose homeostasis was assessed with OGTT and HbA1c in 167 women with HFDP, 4-12 weeks after delivery. Glucose status was based on American Diabetes Association criteria.

RESULTS

Glucose homeostasis was assessed at 10 weeks (IQR 7-12) after delivery. Of the 167 participants, 52 (31%) had hyperglycemia, which was comprised of 34 (20%) prediabetes and 18 (11%) T2DM. Twelve women in the prediabetes subgroup had diagnostic fasting plasma glucose (FPG) and 2-hour plasma glucose (2hPG), but in two-thirds of the patients (22/34) only one time point proved diagnostic. The FPGs and the 2hPGs of six women with HbA1c-based T2DM were both within the prediabetes diagnostic range. According to the HbA1c measurements, 85% of 52 participants with gold standard OGTT defined hyperglycemia (prediabetes and T2DM) as well as 15 of 18 women with postpartum persistent T2DM were correctly classified. According to FPG, 15 women with persistent hyperglycemia would have been missed (11 with prediabetes and four with T2DM; 29%). When compared to an OGTT, a single HbA1c of 6.5% (48mmol/mol) postpartum demonstrated a sensitivity of 83% and specificity of 97% for the identification of T2DM.

CONCLUSION

HbA1c may improve access to postpartum testing in overburdened clinical settings where the required standards of OGTT cannot be guaranteed. HbA1c is a valuable test to detect women who will benefit most from early intervention but cannot unequivocally replace OGTT.

The clinical significance of serum HbA1c to diagnose diabetes mellitus during acute pancreatitis

AIMS

To investigate the prevalence of diabetes mellitus (DM) in acute pancreatitis (AP) patients and to explore the extent to which inflammatory stress affects plasma glucose (PG) levels in AP patients.

METHODS

A retrospective analysis of 2163 AP patients was performed. The PG differences among AP patients under differing pancreatic necrosis conditions and inflammation severity were compared. Receiver operating characteristic curves were used to assess whether fasting PG in the inflammatory stage of AP might be used for DM screening.

RESULTS

The overall DM prevalence was 19.97% in AP patients, 32.41% of whom had newly diagnosed DM (based on HbA1c levels in patients who self-reported no DM). The DM prevalence was 46.93% in hyperlipidemic AP patients, 44.14% of whom had newly diagnosed DM. In patients with and without pancreatic necrosis, the optimal PG thresholds for the screening of newly diagnosed DM were 10.40 mmol/L and 8.21 mmol/L, respectively, with an AUC of 0.959 ± 0.034 (P < 0.001) and 0.972 ± 0.006 (P < 0.001), respectively.

CONCLUSIONS

For hospitalized AP patients and fasting PG levels exceeding 10 mmol/L (with necrosis) or 8 mmol/L (without necrosis) (P < 0.001), HbA1c testing is recommended to investigate the presence of comorbid undiagnosed DM.

Estimating the changing burden of disease attributable to high fasting plasma glucose in South Africa for 2000, 2006 and 2012

Background. Worldwide, higher-than-optimal fasting plasma glucose (FPG) is among the leading modifiable risk factors associated with all- cause mortality and disability-adjusted life years (DALYs) due to the direct sequelae of diabetes and the increased risk for cardiovascular and chronic kidney disease. Objectives. To report deaths and DALYs of health outcomes attributable to high FPG by age and sex for South Africa (SA) for 2000, 2006 and 2012. Methods. Comparative risk assessment methodology was used to estimate the burden attributable to high FPG. A meta-regression analysis was performed using data from national and small-area studies to estimate the population distribution of FPG and diabetes prevalence. Attributable fractions were calculated for selected health outcomes and applied to local burden estimates from the second South African National Burden of Disease Study (SANBD2). Age-standardised rates were calculated using World Health Organization world standard population weights. Results. We estimated a 5% increase in mean FPG from 5.31 (95% confidence interval (CI) 5.18 - 5.43) mmol/L to 5.57 (95% CI 5.41 - 5.72) mmol/L and a 75% increase in diabetes prevalence from 7.3% (95% CI 6.7 - 8.3) to 12.8% (95% CI 11.9 - 14.0) between 2000 and 2012. The age-standardised attributable death rate increased from 153.7 (95% CI 126.9 - 192.7) per 100 000 population in 2000 to 203.5 (95% CI 172.2 - 240.8) per 100 000 population in 2012, i.e. a 32.4% increase. During the same period, age-standardised attributable DALY rates increased by 43.8%, from 3 000 (95% CI 2 564 - 3 602) per 100 000 population in 2000 to 4 312 (95% CI 3 798 - 4 916) per 100 000 population in 2012. In each year, females had similar attributable death rates to males but higher DALY rates. A notable exception was tuberculosis, with an age-standardised attributable death rate in males double that in females in 2000 (14.3 v. 7.0 per 100 000 population) and 2.2 times higher in 2012 (18.4 v. 8.5 per 100 000 population). Similarly, attributable DALY rates were higher in males, 1.7 times higher in 2000 (323 v. 186 per 100 000 population) and 1.6 times higher in 2012 (502 v. 321 per 100 000 population). Between 2000 and 2012, the age-standardised death rate for chronic kidney disease increased by 98.3% (from 11.7 to 23.1 per 100 000 population) and the DALY rate increased by 116.9% (from 266 to 578 per 100 000 population). Conclusion. High FPG is emerging as a public health crisis, with an attributable burden doubling between 2000 and 2012. The consequences are costly in terms of quality of life, ability to earn an income, and the economic and emotional burden on individuals and their families. Urgent action is needed to curb the increase and reduce the burden associated with this risk factor. National data on FPG distribution are scant, and efforts are warranted to ensure adequate monitoring of the effectiveness of the interventions.

Glycated haemoglobin and fasting plasma glucose tests in the screening of outpatients for diabetes and abnormal glucose regulation in Uganda: A diagnostic accuracy study

Background and objectives

To understand the utility of glycated haemoglobin (HBA_1C) in screening for diabetes and Abnormal Glucose Regulation (AGR) in primary care, we compared its performance to that of the fasting plasma glucose (FPG) test.

Methods

This was a prospective diagnostic accuracy study conducted in eastern Uganda. Patients eligible for inclusion were consecutive adults, 30–75 years, receiving care at the outpatient department of a general hospital in eastern Uganda. We determined the sensitivity, specificity and optimum cut-off points for HBA_1C and FPG tests using the oral glucose tolerance test (OGTT) as a clinical reference standard.

Results

A total of 1659 participants underwent FPG testing of whom 310 were also HBA_1C and OGTT tested. A total of 113 tested positive for diabetes and 168 for AGR on the OGTT. At recommended cut-off points for diabetes, the HBA_1C and FPG tests had comparable sensitivity [69.8% (95% CI 46.3–86.1) versus 62.6% (95% CI 41.5–79.8), respectively] and specificity [98.6% (95% CI 95.4–99.6) versus 99.4% (95% CI 98.9–99.7), respectively]. Similarly, the sensitivity of HBA_1C and the FPG tests for Abnormal Glucose Regulation (AGR) at ADA cut-offs were comparable [58.9% (95% CI 46.7–70.2) vs 47.7% (95% CI 37.3–58.4), respectively]; however, the HBA_1C test had lower specificity [70.7% (95% CI 65.1–75.8)] than the FPG test [93.5% (95% CI 88.6–96.4)]. At the optimum cut-offs points for diabetes [45.0 mmol/mol (6.3%) for HBA_1C and 6.4 mmol/L (115.2 mg/dl) for FPG], HBA_1C and FPG sensitivity [71.2% (95% CI 46.9–87.8) versus 72.7% (95% CI 49.5–87.8), respectively] and specificity [95.1% (95% CI91.8 97.2) versus 98.7% (95% CI 98.0 99.2), respectively] were comparable. Similarly, at the optimum cut-off points for AGR [42.0 mmol/mol (6.0%) for the HBA_1C and 5.5 mmol/l (99.0 mg/dl) for the FPG test], HBA_1C and FPG sensitivity [42.3% (95% CI 31.8–53.6) and 53.2 (95% CI 43.1–63.1), respectively] and specificity [89.1% (95% CI 84.1 92.7) and 92.7% (95% CI 91.0 94.1), respectively] were comparable.

Discussion

HBA_1C is a viable alternative diabetes screening and confirmatory test to the FPG test; however, the utility of both tests in screening for prediabetes in this outpatient population is limited.

The Healthy Aging Adult South Africa report card: a systematic review of the evidence between 2013 and 2020 for middle-aged South African men and women

Due to the increasing non-communicable disease burden in Africa, several strategies that target the major lifestyle and physiological risk factors have been implemented to combat such diseases. The Healthy Aging Adult South Africa report card systematically reviews national and regional prevalence data of middle-aged South African adults (45-65 years) published between 2013 and 2020 on diet, physical activity, tobacco use and alcohol consumption, obesity, hypertension, dyslipidaemia and diabetes mellitus. Each indicator was assigned two grades, (1) based on the availability of prevalence data, and (2) based on whether policies have been proposed and implemented for the respective indicators. Alcohol consumption, obesity, hypertension and diabetes received an A grade for the availability of prevalence data. Tobacco use and diet received an A grade for policy and implementation. Gaps have been identified that need to be filled by future research focusing on continued surveillance of all indicators in order to inform and implement effective policies.

Type 2 diabetes mellitus in sub-Saharan Africa: challenges and opportunities

Type 2 diabetes mellitus (T2DM), which was once thought to be rare in sub-Saharan Africa (SSA), is now well established in this region. The SSA region is undergoing a rapid but variable epidemiological transition fuelled by the pace of urbanization, with disease burden profiles shifting from communicable diseases to non-communicable diseases (NCDs). Information on the epidemiology of T2DM has increased, but wide variations in study methods, diagnostic biomarkers and criteria hamper analytical comparison, and data from high-quality studies are limited. The prevalence of T2DM is still low in some rural populations but moderate or high rates are reported in many countries/regions, with evidence for an increase in some. In addition, the proportion of undiagnosed T2DM is still high. The prevalence of T2DM is highest in African people living in urban areas, and the gradient between African people living in urban areas and people in the African diaspora is rapidly fading. However, data from longitudinal studies are lacking and there is limited information on chronic complications and the genetics of T2DM. The large unmet needs for T2DM care call for greater investment of resources into health systems to manage NCDs in SSA. Proposed health-system paradigms are being developed in some countries/regions. However, national NCD programmes need to be adequately funded and coordinated to stem the tide of T2DM and its complications.

The diagnostic accuracy of HbA1c , compared to the oral glucose tolerance test, for screening for type 2 diabetes mellitus in Africa-A systematic review and meta-analysis

OBJECTIVE

To assess the diagnostic accuracy of glycated haemoglobin A_1c (HbA_1c ), compared to fasting plasma glucose (FPG) and the oral glucose tolerance test (OGTT), in screening for type 2 diabetes (T2D) in Africa.

METHODS

We systematically searched databases for studies that compared the HbA_1c to either the OGTT, or the FPG for T2D diagnosis were included. The QUADAS 2 tool was used for assessing the quality of included studies. We used the split component synthesis (SCS) method for the meta-analysis of diagnostic accuracy studies to pool the studies for meta-analysis of sensitivity and specificity, primarily at the HbA_1c ≥48 mmol/mol (6.5%) cut-off and at other cut-offs. We assessed heterogeneity using the I²  statistic and publication bias using Doi plots.

RESULTS

Eleven studies, from seven African countries, with 12,925 participants, were included. Against the OGTT, HbA_1c ≥48 mmol/mol (6.5%) had a pooled sensitivity of 57.7% (95% confidence interval [CI] 43.4-70.9) and specificity of 92.3% (95% CI 83.9-96.5). Against the FPG, HbA_1c ≥48 mmol/mol (6.5%) had a pooled sensitivity of 64.5% (95% CI 50.5-76.4) and specificity of 94.3% (95% CI 87.9-97.5). The highest sensitivity for HbA_1c , against the OGTT, was at the 42 mmol/mol (6.0%) cut-off.

CONCLUSION

In Africa, the HbA_1c ≥48 mmol/mol (6.5%) cut-off may miss almost half of the individuals with T2D based on blood glucose measures.

Relationships between adiposity distribution and metabolic health in preconception women in South Africa

Objective

Adipose tissue is a central regulator of metabolic health and a contributor to systemic inflammation. Patterns of adiposity deposition are important to understand for optimizing health. This study aimed to asses relationships between adiposity deposition and metabolic and inflammatory biomarkers in South African women prior to conception.

Methods

Non‐pregnant, healthy women (n = 298) were recruited for this cross‐sectional study via home visits. Body composition was measured by Dual X‐ray Absorptiometry. Inflammation markers C‐reactive protein (CRP), alpha1‐acid glycoprotein (AGP), hemoglobin A1c (HbA1c), and blood pressure were scored according to risk. A summative metabolic health risk score was created for women with obesity. Generalized regression models assessed relationships between adiposity deposition and outcomes with adjustment for potential confounders.

Results

Obesity was present in 22% of women (mean age = 20.93 years). Fat mass index was associated with inflammation and metabolic health risk (β = 0.58; p < 0.01). Visceral fat, trunk:limb ratio, android:gynoid ratio, body mass index, weight, and waist circumference were positively associated with CRP, AGP, and metabolic health risk (p < 0.01). Weight was associated with Hba1c (β < 0.01; p < 0.05). Participants with obesity and low metabolic health risk had lower fat mass index and visceral fat than participants with obesity and higher metabolic health risk.

Conclusions

Black South African women accumulated excess adipose tissue in abdominal regions. While fat mass and body mass were associated with inflammation and metabolic health risk, women with obesity and with lower fat mass index and lower visceral adipose tissue were metabolically protected. Identification of women at risk for metabolic disease preconception could help ensure future healthy pregnancies and prevent transference of risk to offspring.

HIV infection and anaemia do not affect HbA1c for the detection of diabetes in black South Africans: Evidence from the Durban Diabetes Study

OBJECTIVE

South Africa has a high burden of HIV infection and anaemia. These conditions may cause HbA_1c to over- or underestimate glycaemia; however, this has not been comprehensively investigated in African populations. We assessed the association of anaemia, HIV infection and antiretroviral therapy (ART) with HbA_1c , and implications for the detection and diagnosis of diabetes, in a black South African population.

RESEARCH DESIGN AND METHODS

In this population-based cross-sectional study in eThekwini municipality (Durban), South Africa, we assessed HbA_1c and conducted oral glucose tolerance tests (OGTTs), HIV diagnostic tests and full blood count measurements among 1067 participants without a history of diabetes diagnosis. Linear regression was used to examine differences in HbA_1c by anaemia (comparator: no anaemia), or HIV and ART (comparator: no HIV) status. HbA_1c -based diabetes prevalence was compared with OGTT-based prevalence among individuals with anaemia and with untreated and ART-treated HIV.

RESULTS

In adjusted analyses, normocytic and microcytic anaemia were associated with higher HbA_1c compared with no anaemia, whereas macrocytic anaemia and ART-treated HIV were associated with lower HbA_1c compared with no anaemia and no HIV, respectively. However, magnitudes of association were small (range: β  = -3.4 mmol/mol or -0.31%, p < 0.001 [macrocytic anaemia] to β = 2.1 mmol/mol or 0.19%, p < 0.001 [microcytic anaemia]). There was no significant difference in diabetes prevalence based on HbA_1c or OGTT among individuals with anaemia (2.9% vs. 3.3%, p = 0.69), untreated HIV (1.6% vs. 1.6% p = 1.00) or ART-treated HIV (2.9% vs. 1.2%, p = 0.08).

CONCLUSIONS

Our results suggest that anaemia and HIV status appear unlikely to materially affect the utility of HbA_1c for diabetes detection and diagnosis in this population. Further studies are needed to examine these associations in sub-Saharan African populations.

Prevalence and correlates of pre-diabetes in adults of mixed ethnicities in the South African population: a systematic review and meta-analysis protocol

INTRODUCTION

Pre-diabetes is a metabolic condition characterised by moderate glycaemic dysregulation and is a front-line risk factor to multiple metabolic complications such as overt diabetes. To the best of our knowledge, this will be the first systematic review and meta-analysis that focuses on generating a comprehensive pooling of studies that report on the pre-diabetes prevalence in South Africa. Therefore, the review's purpose will be to screen and elect reports that can be used to synthesise and provide the best estimate prevalence and correlate of pre-diabetes in the South African population.

METHODS AND ANALYSIS

To determine the prevalence and correlates of pre-diabetes in South African, we will search PubMed, Embase and African Journal online for published or unpublished studies reporting the prevalence of pre-diabetes in South Africa starting from the year 2000 to 2020. Studies will be assessed for eligibility by checking if they meet the inclusion criteria. Eligible studies will undergo data extraction and risk of bias assessment. We will perform a subgroup analysis to detect probable causes of heterogeneity.

ETHICS AND DISSEMINATION

The review will not require ethics clearance because non-identifiable data will be used. The review outcomes will give more insight into the current burden that pre-diabetes has in South Africa.

PROSPERO REGISTRATION NUMBER

CRD42020182430.

Clinic-based diabetes screening at the time of HIV testing and associations with poor clinical outcomes in South Africa: a cohort study

BACKGROUND

HIV clinical care programs in high burden settings are uniquely positioned to facilitate diabetes diagnosis, which is a major challenge. However, in sub-Saharan Africa, data on the burden of diabetes among people living with HIV (PLHIV) and its impact on HIV outcomes is sparse.

METHODS

We enrolled adults presenting for HIV testing at an outpatient clinic in Durban. Those who tested positive for HIV-infection were screened for diabetes using a point-of-care hemoglobin A1c (HbA1c) test. We used log-binomial, Poisson, and Cox proportional hazard models adjusting for confounders to estimate the relationship of diabetes (HbA1c ≥ 6.5%) with the outcomes of HIV viral suppression (< 50 copies/mL) 4-8 months after antiretroviral therapy initiation, retention in care, hospitalization, tuberculosis, and death over 12 months.

RESULTS

Among 1369 PLHIV, 0.5% (n = 7) reported a prior diabetes diagnosis, 20.6% (95% CI 18.5-22.8%, n = 282) screened positive for pre-diabetes (HbA1c 5.7-6.4%) and 3.5% (95% CI 2.7-4.6%, n = 48) for diabetes. The number needed to screen to identify one new PLHIV with diabetes was 46.5 persons overall and 36.5 restricting to those with BMI ≥ 25 kg/m2. Compared to PLHIV without diabetes, the risk of study outcomes among those with diabetes was not statistically significant, although the adjusted hazard of death was 1.79 (95% CI 0.41-7.87).

CONCLUSIONS

Diabetes and pre-diabetes were common among adults testing positive for HIV and associated with death. Clinic-based diabetes screening could be targeted to higher risk groups and may improve HIV treatment outcomes.

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

OBJECTIVES

We investigated concordance between haemoglobin A1c (HbA₁c)-defined diabetes and fasting plasma glucose (FPG)-defined diabetes in a black South African population with a high prevalence of obesity.

DESIGN

Cross-sectional study.

SETTING

Rural South African population-based cohort.

PARTICIPANTS

765 black individuals aged 40-70 years and with no history of diabetes.

PRIMARY AND SECONDARY OUTCOME MEASURES

The primary outcome measure was concordance between HbA_1c-defined diabetes and FPG-defined diabetes. Secondary outcome measures were differences in anthropometric characteristics, fat distribution and insulin resistance (measured using Homoeostatic Model Assessment of Insulin Resistance (HOMA-IR)) between those with concordant and discordant HbA_1c/FPG classifications and predictors of HbA_1c variance.

RESULTS

The prevalence of HbA_1c-defined diabetes was four times the prevalence of FPG-defined diabetes (17.5% vs 4.2%). Classification was discordant in 15.7% of participants, with 111 individuals (14.5%) having HbA_1c-only diabetes (kappa 0.23; 95% CI 0.14 to 0.31). Median body mass index, waist and hip circumference, waist-to-hip ratio, subcutaneous adipose tissue and HOMA-IR in participants with HbA_1c-only diabetes were similar to those in participants who were normoglycaemic by both biomarkers and significantly lower than in participants with diabetes by both biomarkers (p<0.05). HOMA-IR and fat distribution explained additional HbA_1c variance beyond glucose and age only in women.

CONCLUSIONS

Concordance was poor between HbA_1c and FPG in diagnosis of diabetes in black South Africans, and participants with HbA_1c-only diabetes phenotypically resembled normoglycaemic participants. Further work is necessary to determine which of these parameters better predicts diabetes-related morbidities in this population and whether a population-specific HbA_1c threshold is necessary.

Prevalence of Type 2 Diabetes in South Africa: A Systematic Review and Meta-Analysis

Synthesis of existing prevalence data using rigorous systematic review methods is considered an effective strategy to generate representative and robust prevalence figures to inform health planning and policy. The purpose of this systematic review was to identify, collate, and synthesise all studies reporting the prevalence of total and newly diagnosed type 2 diabetes (T2DM), impaired glucose tolerance (IGT), and impaired fasting glucose (IFG) in South Africa. Four databases, PubMed, Scopus, Web of Science, and African Index Medicus were searched for articles published between January 1997 and June 2020. A total of 1886 articles were identified, of which 11 were included in the meta-analysis. The pooled prevalence in individuals 25 years and older was 15.25% (11.07–19.95%) for T2DM, 9.59% (5.82–14.17%) for IGT, 3.55% (0.38–9.61%) for IFG, and 8.29% (4.97–12.34%) for newly diagnosed T2DM. Although our pooled estimate may be imprecise due to significant heterogeneity across studies with regard to population group, age, gender, setting, diagnostic test, and study design, we provide evidence that the burden of glucose intolerance in South Africa is high. These factors contribute to the paucity of representative T2DM prevalence data. There is a need for well-designed epidemiological studies that use best-practice and standardised methods to assess prevalence.

Performance of diabetes screening tests: an evaluation study of Iranian diabetes screening program

BACKGROUND

Type 2 diabetes is a common non-communicable disease that is responsible for about 9% of all deaths and a 25% reduction in life expectancy. However, nearly half of the diabetic patients are not aware of their disease. In this regard, to identify un-known diabetic patients, diabetes screening is of great importance. This study was conducted to evaluate the performance of two commonly used diabetes screening tests that are currently recommended by the Iranian diabetes screening program for (DSP).

METHODS

The validity of the two diabetes screening tests were measured among 1057 participants who were older than 30 years of age. The studied screening tests included capillary fasting blood glucose (CBG) and glycated hemoglobin (HbA1c). The golden standard for measuring the validity of the tests was venous fasting plasma glucose (VPG).

RESULTS

According to the results, the sensitivity of CBG and HbA1c tests was 69.01% and 84.5%, and the specificity of the tests were 95.7% and 79.3%, respectively. Positive and negative predictive values were 53.84% and 97.72% for CBG and 22.72% and 98.61% for HbA1c, respectively. The recommended cut points for CBG and HbA1c were 116.5 mg/dl and 7.15%, respectively. Using these values as the new cut points, sensitivity and specificity of CBG and HbA1c changed to 80.30% and 89.10%, and 77.50% and 94.20%, respectively.

CONCLUSIONS

Compared to several other countries, the performance of Iranian DSP is relatively better. The Receiver Operating Characteristic Curve suggested new cut points for significantly better performance of DSP.

Polymorphic genetic markers and how they are associated with clinical and metabolic indicators of type 2 diabetes mellitus in the Kazakh population

Background

Type 2 diabetes mellitus is a serious public health problem worldwide. The aim of the study was to analyze the relationship of eight polymorphic gene variants with the development of clinical-metabolic rates of type 2 diabetes mellitus inside Kazakh population.

Materials and methods

139 patients with type 2 diabetes mellitus and 100 patients in the control group were examined. Genotyping of polymorphisms of candidate genes was carried out on a next generation QuantStudio 12 K Flex unit.

Results

Gene TCF7L2 locus rs7901695 and rs7903146, gene KCNQ1 locus rs2237892, rs7756992, and gene CDKAL1 locus rs7754840 demonstrated statistically significant associations with glucose metabolism, lipid profile and body mass index (BMI) in type 2 DM inside the population. Statistically significant difference in anthropometric and biochemical measures of rs17584499, rs4712523 and rs163184 has not been revealed.

Conclusions

Genetic polymorphisms that influence pancreatic gland beta-cells insulin release and secretion associate with metabolic and anthropometric measures definitive for type 2 DM in Kazakh population.

Diagnostic accuracy of tests for type 2 diabetes and prediabetes: A systematic review and meta-analysis

Aim

This systematic review aimed to ascertain the diagnostic accuracy (sensitivity and specificity) of screening tests for early detection of type 2 diabetes and prediabetes in previously undiagnosed adults.

Methods

This systematic review included published studies that included one or more index tests (random and fasting tests, HbA1c) for glucose detection, with 75-gram Oral Glucose Tolerance Test (or 2-hour post load glucose) as a reference standard (PROSPERO ID CRD42018102477). Seven databases were searched electronically (from their inception up to March 9, 2020) accompanied with bibliographic and website searches. Records were manually screened and full text were selected based on inclusion and exclusion criteria. Subsequently, data extraction was done using standardized form and quality assessment of studies using QUADAS-2 tool. Meta-analysis was done using bivariate model using Stata 14.0. Optimal cut offs in terms of sensitivity and specificity for the tests were analysed using R software.

Results

Of 7,151 records assessed by title and abstract, a total of 37 peer reviewed articles were included in this systematic review. The pooled sensitivity, specificity, positive (LR+) and negative likelihood ratio (LR-) for diagnosing diabetes with HbA1c (6.5%; venous sample; n = 17 studies) were 50% (95% CI: 42–59%), 97.3% (95% CI: 95.3–98.4), 18.32 (95% CI: 11.06–30.53) and 0.51 (95% CI: 0.43–0.60), respectively. However, the optimal cut-off for diagnosing diabetes in previously undiagnosed adults with HbA1c was estimated as 6.03% with pooled sensitivity of 73.9% (95% CI: 68–79.1%) and specificity of 87.2% (95% CI: 82–91%). The optimal cut-off for Fasting Plasma Glucose (FPG) was estimated as 104 milligram/dL (mg/dL) with a sensitivity of 82.3% (95% CI: 74.6–88.1%) and specificity of 89.4% (95% CI: 85.2–92.5%).

Conclusion

Our findings suggest that at present recommended threshold of 6.5%, HbA1c is more specific and less sensitive in diagnosing the newly detected diabetes in undiagnosed population from community settings. Lowering of thresholds for HbA1c and FPG to 6.03% and 104 mg/dL for early detection in previously undiagnosed persons for screening purposes may be considered.

[Measurement of pupillary diameter in diabetic and non-diabetic patients: a case-control study]

PURPOSE

To study the effect of type 2 diabetes on pupil diameter.

PATIENTS AND METHODS

We carried out a case-control study at the Douala Obstetrics, Gynecology and Pediatric Hospital over a 5-month period. The cases were type 2 diabetic patients, and the controls were non-diabetic patients paired for age and gender. We studied the correlation between the duration of diabetes, fasting blood sugar and the horizontal pupil diameter.

RESULTS

We included 35 patients in each group. The mean age was 56.6±10.01 years. Both groups included 17 males and 18 females. The mean duration of diabetes was 2.72±4.31 years, and the mean fasting blood sugar was 2.02±0.69g/L. The mean pupil diameter was similar in the two groups. On the right side, it was 4.75±0.73mm for controls and 4.52±0.69mm for cases (P=0.179). On the left side, it was 4.70±0.68mm and 4.42±0.73mm respectively for each group (P=0.101). The duration of diabetes was correlated to pupil diameter in the right eye (r=-0.43; P=0.01) and left eye (r=-0.45; P<0.01). No additional risk was found to be associated with diabetes for right pupil diameters (OR=0.79; P=0.33), or for left ones (OR=0.76; P=0.24).

CONCLUSION

Pupil diameter is similar in diabetic and non-diabetic patients. However, the duration of diabetes appears to affect pupil diameter.

Glycated haemoglobin (HbA1c) as a reliable option for detecting diabetes among the urban poor population in Bangladesh

Our previous epidemiological survey targeting urban slum dwellers in Bangladesh showed that the prevalence of diabetes defined by glycated haemoglobin (HbA1c) was higher than the national estimation, and higher in women than men. Subsequently, we conducted the oral glucose tolerance test (OGTT) and found that HbA1c values were consistent with the OGTT findings for detecting diabetes. Our findings indicated that HbA1c ≥6.5% was a rational cut-off, but the optimal HbA1c cut-off for this population might be lower than the internationally recommended threshold. Measuring HbA1c would be a reliable and feasible option for detecting diabetes among underprivileged population in developing countries.

Assessment of diabetes and prediabetes prevalence and predictors by HbA1c in a population from sub-Saharan Africa with a high proportion of anemia: a prospective cross-sectional study

INTRODUCTION

Epidemiological data about diabetes mellitus (DM) for sub-Saharan Africa (SSA) are scarce and the utility of glycated hemoglobin (HbA1c) to diagnose DM is uncertain in African populations with a high proportion of anemia.

RESEARCH DESIGN AND METHODS

In a cross-sectional study, age-adjusted prevalence rates and predictors for DM and pre-DM were prospectively assessed by HbA1c in a semirural walk-in population of Tanzania (n=992). Predictors for DM were calculated by logistic regression. Correlations between HbA1c, hemoglobin, and blood glucose levels were done by Pearson's correlation.

RESULTS

Overall, DM and pre-DM prevalence rates were 6.8% (95% CI 5.3 to 8.5) and 25% (95% CI 22.8 to 28.3), respectively. There was an increase in DM prevalence in patients 50-59 (14.9%; 95% CI 9.1 to 22.5), ≥60 years old (18.5%; 95% CI 12.2 to 26.2) and in patients with overweight (9.3%; 95% CI 5.9 to 13.7), obesity (10.9%; 95% CI 6.9 to 16) compared with patients 18-29 years old (2.2%; 95% CI 0.9 to 4.4) (p<0.001) and to normal-weight patients (3.6%; 95% CI 2.1 to 5.6) (p<0.01), respectively. Age (OR 1.08, 95% CI 1.05 to 1.12; p<0.001), body mass index (BMI) (OR 1.10, 95% CI 1.04 to 1.16; p<0.001), and acute infection (OR 3.46, 95% CI 1.02 to 10.8; p=0.038) were predictors for DM. Comparing patients with a BMI of 20 kg/m² and a BMI of 35 kg/m², the relative risk for DM increases in average by 2.12-fold (range 1.91-2.24) across the age groups. Comparing patients 20 years old with patients 70 years old, the relative risk for DM increases in average 9.7-fold (range 8.9-10.4) across the BMI groups. Overall, 333 patients (36%) suffered from anemia. Pearson's correlation coefficients (r) between HbA1c and hemoglobin was -0.009 (p=0.779), and between HbA1c and fasting blood glucose and random blood glucose, it was 0.775 and 0.622, respectively (p<0.001).

CONCLUSION

We observed a high prevalence of DM and pre-DM, mainly triggered by increasing age and BMI, and provide evidence that HbA1c is suitable to assess DM also in populations of SSA with high proportions of anemia.

TRIAL REGISTRATION NUMBER

NCT03458338.

ZRANB3 is an African-specific type 2 diabetes locus associated with beta-cell mass and insulin response

Genome analysis of diverse human populations has contributed to the identification of novel genomic loci for diseases of major clinical and public health impact. Here, we report a genome-wide analysis of type 2 diabetes (T2D) in sub-Saharan Africans, an understudied ancestral group. We analyze ~18 million autosomal SNPs in 5,231 individuals from Nigeria, Ghana and Kenya. We identify a previously-unreported genome-wide significant locus: ZRANB3 (Zinc Finger RANBP2-Type Containing 3, lead SNP p = 2.831 × 10⁻⁹). Knockdown or genomic knockout of the zebrafish ortholog results in reduction in pancreatic β-cell number which we demonstrate to be due to increased apoptosis in islets. siRNA transfection of murine Zranb3 in MIN6 β-cells results in impaired insulin secretion in response to high glucose, implicating Zranb3 in β-cell functional response to high glucose conditions. We also show transferability in our study of 32 established T2D loci. Our findings advance understanding of the genetics of T2D in non-European ancestry populations.

Type 2 diabetes (T2D) is prevalent in populations worldwide, however, mostly studied in European and mixed-ancestry populations. Here, the authors perform a genome-wide association study for T2D in over 5,000 sub-Saharan Africans and identify a locus, ZRANB3, that is specific for this population.

Genome-wide association study of type 2 diabetes in Africa

AIMS/HYPOTHESIS

Genome-wide association studies (GWAS) for type 2 diabetes have uncovered >400 risk loci, primarily in populations of European and Asian ancestry. Here, we aimed to discover additional type 2 diabetes risk loci (including African-specific variants) and fine-map association signals by performing genetic analysis in African populations.

METHODS

We conducted two type 2 diabetes genome-wide association studies in 4347 Africans from South Africa, Nigeria, Ghana and Kenya and meta-analysed both studies together. Likely causal variants were identified using fine-mapping approaches.

RESULTS

The most significantly associated variants mapped to the widely replicated type 2 diabetes risk locus near TCF7L2 (p = 5.3 × 10^-13). Fine-mapping of the TCF7L2 locus suggested one type 2 diabetes association signal shared between Europeans and Africans (indexed by rs7903146) and a distinct African-specific signal (indexed by rs17746147). We also detected one novel signal, rs73284431, near AGMO (p = 5.2 × 10^-9, minor allele frequency [MAF] = 0.095; monomorphic in most non-African populations), distinct from previously reported signals in the region. In analyses focused on 100 published type 2 diabetes risk loci, we identified 21 with shared causal variants in African and non-African populations.

CONCLUSIONS/INTERPRETATION

These results demonstrate the value of performing GWAS in Africans, provide a resource to larger consortia for further discovery and fine-mapping and indicate that additional large-scale efforts in Africa are warranted to gain further insight in to the genetic architecture of type 2 diabetes.

Reference interval determination for glycated albumin in defined subgroups of a South African population

Background

Glycated proteins, such as glycated haemoglobin (HbA1c) and glycated albumin (GA%), are increasingly being used for glycaemic control assessment and the diagnosis of diabetes mellitus. GA% is an intermediate marker of glycaemic control that is not influenced by factors that affect HbA1c concentrations. The aim of this study was to determine reference intervals and assess confounding factors for glycated albumin in a well-characterized healthy population in South Africa.

Methods

We measured glycated albumin using an enzymatic method on stored serum samples of healthy individuals recruited in Cape Town, South Africa. Reference intervals (overall and specific for age, sex and ethnicity) were determined using non-parametric methods and confounding factors were assessed using multiple regression analysis.

Results

The reference interval (2.5th to 97.5th percentile) for glycated albumin of 663 healthy individuals (mean age, 34 years, 38.6% males) ranged from 10.7 to 15.2%. Sex, body mass index categories and ethnicity were significantly associated with the glycated albumin and were considered of practical importance because their standardized regression coefficients (Beta) were greater than a cut-off of 0.15, implying a stronger effect on glycated albumin ( P < 0.001). The glycated albumin reference intervals for subjects with body mass index <25 kg/m2 was 11.2–15.3%, for body mass index 25–30 kg/m2 it was 10.5–14.9% and 10.0–14.6% for body mass index >30 kg/m2 ( P = 0.0001).

Conclusions

The overall reference interval showed good correlation with reference intervals determined in other studies. However, sex, ethnicity and body mass index were statistically significant confounding factors that may influence the overall reference interval. Therefore, overall glycated albumin reference intervals should be used cautiously.

Prediabetes management in the Middle East, Africa and Russia: Current status and call for action

Most data on the burden of diabetes and prediabetes are from countries where local infrastructure can support reliable estimates of the burden of non-communicable diseases. Countries in the Middle East and Africa, together with Russia, have a total population of almost 2 billion, but have been relatively overlooked by authors in this field. We reviewed the prevalence and drivers of prediabetes and diabetes across this large region. A large, and variable, burden of dysglycaemia exists, especially in Middle Eastern and North African countries, associated with high levels of obesity and sedentariness, with a generally lower prevalence in most other parts of Africa. The design and size of studies are highly variable, and more research to quantify the scale of the problem is needed. Local barriers to care relating to issues concerned with gender, consanguinity, lack of understanding of diabetes, lack of understanding of obesity as a health issue, and limited resource at a national level for tracking and intervention for diabetes and other non-communicable diseases. Lifestyle interventions with proven local cost-effectiveness, enhanced access to pharmacologic intervention, and societal interventions to promote better diet and more activity will be an important element in strategies to combat these adverse trends.

Evidence for the utility of antenatal HbA1c to predict early postpartum diabetes after gestational diabetes in South Africa

Aim To evaluate antenatal HbA1c at diagnosis and in the 4 weeks preceding delivery to predict early postpartum diabetes mellitus (DM) in women with Gestational Diabetes Mellitus (GDM). Methods Seventy-eight women with GDM were prospectively assessed. The ability of HbA1c at GDM diagnosis (t1) and in the 4 weeks preceding delivery (t2) to predict DM 6-12 weeks after delivery was investigated. Glucose assessment was performed between November 1, 2015, and November 1, 2016 at Tygerberg Hospital (TH), Cape Town, South Africa (SA). Individuals with known pre-existing diabetes were excluded. Results HbA1c of 6.2% (44 mmol/mol) and 6.5% (48 mmol/mol) at t1 predicted DM with sensitivities of 95% and 90% and specificities of 62% and 70% respectively. At t2 the best cut-off for HbA1c, in accordance with t1, was also 6.2% (44 mmol/mol; sensitivity 92%, specificity 56%). Nineteen of the 29 women with suspected pre-gestational DM had HbA1c levels ≥ 6.5% (48 mmol/mol) at t1. The increased risk for postpartum DM with HbA1c ≥ 6.2% (44 mmol/mol) was four-fold (OR 3.97 CI 2.08-7.59p < 0.001) at t1 and five-fold (OR 5.08 CI 1.60-16.25 p = 0.006) at t2. Conclusion HbA1c lower than 6.5% (48 mmol/mol) predicts postpartum DM in women with GDM. HbA1c can serve as instrument to improve postpartum follow-up.

The prevalence of type 2 diabetes in South Africa: a systematic review protocol

INTRODUCTION

Type 2 diabetes mellitus is a major source of morbidity and mortality in South Africa, spurred by increased urbanisation and unhealthy lifestyle factors. Local epidemiological data are required to inform health planning and policy. The purpose of this systematic review is to identify, collate and synthesise all studies reporting the prevalence of diabetes in South Africa. A secondary aim is to report the prevalence of impaired glucose tolerance and impaired fasting glucose, conditions which are associated with an increased risk of progression to overt diabetes, and the prevalence of undiagnosed diabetes.

METHODS AND ANALYSIS

Multiple databases will be searched for diabetes prevalence studies conducted in South Africa between 1997 and 2018. Two authors will independently select studies that meet the inclusion criteria, extract data and appraise studies using a risk of bias tool for prevalence studies. Studies with low or moderate risk of bias will be included. Sources of heterogeneity will be explored using subgroup analysis.

ETHICS AND DISSEMINATION

The systematic review does not require ethics clearance since published studies with non-identifiable data will be used. This review will provide best estimates to inform the Second National Burden of Disease study which can guide health and policy planning.

PROSPERO REGISTRATION NUMBER

CRD42017071280.

Glycated haemoglobin A1c (HbA1c) for detection of diabetes mellitus and impaired fasting glucose in Malawi: a diagnostic accuracy study

OBJECTIVES

To examine the accuracy of glycated haemoglobin A_1c (HbA_1c) in detecting type 2 diabetes and impaired fasting glucose among adults living in Malawi.

DESIGN

A diagnostic validation study of HbA_1c. Fasting plasma glucose (FPG) ≥7.0 mmol/L was the reference standard for type 2 diabetes, and FPG between 6.1 and 6.9 mmol/L as impaired fasting glucose.

PARTICIPANTS

3645 adults (of whom 63% were women) recruited from two demographic surveillance study sites in urban and rural Malawi. This analysis excluded those who had a previous diagnosis of diabetes or had history of taking diabetes medication.

RESULTS

HbA_1c demonstrated excellent validity to detect FPG-defined diabetes, with an area under the receiver operating characteristic (AUROC) curve of 0.92 (95% CI 0.90 to 0.94). At HbA_1c ≥6.5% (140 mg/dL), sensitivity was 78.7% and specificity was 94.0%. Subgroup AUROCs ranged from 0.86 for participants with anaemia to 0.94 for participants in urban Malawi. There were clinical and metabolic differences between participants with true diabetes versus false positives when HbA_1c was ≥6.5% (140 mg/dL).

CONCLUSIONS

The findings from this study provide justification to use HbA_1c to detect type 2 diabetes. As HbA_1c testing is substantially less burdensome to patients than either FPG testing or oral glucose tolerance testing, it represents a useful option for expanding access to diabetes care in sub-Saharan Africa.

Access to Hemoglobin A1c in Rural Africa: A Difficult Reality with Severe Consequences

Sub-Saharan Africa (SSA) continues to have the highest diabetes-related mortality rate in the world. While there exists a multitude of health system barriers driving poor diabetes control, rural facilities particularly in SSA lack access to proper monitoring of glucose and other key biologic tests. At best, most of these diabetes patients receive random blood sugar readings only on the day of their clinic visit. This approach has very limited clinical value in determining dosage adjustments for narrow therapeutic index medications such as insulin. Furthermore, access to other blood tests and physical exam tools for detecting early signs of diabetes complications is limited. We propose that routine access to hemoglobin A1c (HbA1c) testing would not only allow for close monitoring of diabetes control but also provide critical data informing the population level risk for diabetes complications. However, implementing HbA1c testing does have its own barriers at rural facilities, including high costs, refrigeration requirements, and perceived discordance between HbA1c values and mean blood glucose levels for SSA patients. Fortunately, several pilots in rural SSA have illustrated feasibility of HbA1c testing. Further political will, price reduction, and context-specific research are needed. Increasing access to HbA1c testing is a critical step to combat the high diabetes-related mortality rates in rural SSA.

Trilateral overlap of tuberculosis, diabetes and HIV-1 in a high-burden African setting: implications for TB control

The diabetes mellitus burden is growing in countries where tuberculosis (TB) and HIV-1 remain major challenges, threatening TB control efforts. This study determined the association between TB and diabetes/impaired glucose regulation in the context of HIV-1.

A cross-sectional study was conducted at a TB clinic in Cape Town (South Africa). Participants were screened for diabetes and impaired glucose regulation using fasting plasma glucose, oral glucose tolerance test and glycated haemoglobin (HbA1c).

414 TB and 438 non-TB participants were enrolled. In multivariable analysis, diabetes was associated with TB (OR 2.4, 95% CI 1.3–4.3; p=0.005), with 14% population-attributable risk fraction; however, this association varied by diagnostic test (driven by HbA1c). The association remained significant in HIV-1-infected individuals (OR 2.4, 95% CI 1.1–5.2; p=0.030). A high prevalence of impaired glucose regulation (65.2% among TB cases) and a significant association with TB (OR 2.3, 95% CI 1.6–3.3; p<0.001) was also found.

Diabetes and impaired glucose regulation prevalence was high and associated with TB, particularly in HIV-1-infected individuals, highlighting the importance of diabetes screening. The variation in findings by diagnostic test highlights the need for better glycaemia markers to inform screening in the context of TB and HIV-1.

DM/TB association is significant in HIV infection, but more accurate glycaemia markers at TB diagnosis are neededhttp://ow.ly/ZXoS30aPz22

Alternative indices of glucose homeostasis as biochemical diagnostic tests for abnormal glucose tolerance in an African setting

AIMS

Accurate diabetes diagnosis is important in Africa, where rates are increasing, and the disease largely undiagnosed. The cumbersome oral glucose tolerance test (OGTT) remains the reference standard, while alternative diagnostic methods are not yet established in Africans. We assessed the ability of fasting plasma glucose (FPG), HbA1c and fructosamine, to diagnose OGTT-based abnormal glucose tolerance in mixed-ancestry South Africans.

METHODS

Mixed-ancestry adults, residing in Cape Town were examined between February and November 2015. OGTT values were used to classify glucose tolerance status as: screen-detected diabetes, prediabetes, dysglycaemia (combination of diabetes and prediabetes) and normal glucose tolerance.

RESULTS

Of the 793 participants included, 65 (8.2%) had screen-detected diabetes, 157 (19.8%) prediabetes and 571 (72.0%) normal glucose tolerance. Correlations of FPG and 2-h glucose with HbA1c (r=0.51 and 0.52) were higher than those with fructosamine (0.34 and 0.30), both p<0.0001. The highest c-statistic for the prediction of abnormal glucose tolerance was recorded with 2-h glucose [c-statistic=0.997 (screen-detected diabetes), 0.979 (prediabetes) and 0.984 (dysglycaemia)] and the lowest with fructosamine (0.865, 0.596 and 0.677). At recommended or data-specific optimal cut-offs, no combination of FPG, HbA1c and fructosamine did better than 2-h glucose, while FPG was better than HbA1c and fructosamine on a range of performance measures.

CONCLUSIONS

Abnormal glucose tolerance in this population is overwhelmingly expressed through 2-h glucose's abnormalities; and no combination of FPG, HbA1c and fructosamine was effective at accurately discriminating OGTT-defined abnormal glucose tolerance. Tested non-glucose based strategies are unreliable alternatives to OGTT for dysglycaemia diagnosis in this population.