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.

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 HbA1c 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 HbA1c , 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 HbA1c 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 HbA1c by anaemia (comparator: no anaemia), or HIV and ART (comparator: no HIV) status. HbA1c -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 HbA1c compared with no anaemia, whereas macrocytic anaemia and ART-treated HIV were associated with lower HbA1c compared with no anaemia and no HIV, respectively. However, magnitudes of association were small (range: ß  = -3.4 mmol/mol or -0.31%, p < 0.001 [macrocytic anaemia] to ß = 2.1 mmol/mol or 0.19%, p < 0.001 [microcytic anaemia]). There was no significant difference in diabetes prevalence based on HbA1c 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 HbA1c for diabetes detection and diagnosis in this population. Further studies are needed to examine these associations in sub-Saharan African populations.

High frequency of hypoglycaemia in patients with type 1 diabetes mellitus attending a tertiary diabetes clinic in Durban, South Africa.

AIM: The study aimed to assess the prevalence of hypoglycaemia in subjects with type 1 diabetes (T1D) attending a public health tertiary diabetes clinic in Durban, South Africa. METHODS: Patients with T1D were enrolled at the time of clinic attendance. Data on hypoglycaemia over the previous 12 weeks were obtained from glucose meter downloads as well as diary records. Each patient completed the Hypoglycaemia Fear Survey questionnaire as well as an in-house questionnaire on hypoglycaemic episodes in the previous 12 months. RESULTS: A total of 151 subjects (58% female, 54% black African) were enrolled. "Any" hypoglycaemia occurred in 144 (95.4%) in the 12 months prior to clinic attendance. Of these, "severe" hypoglycaemia occurred in 107 (74.3%) and 22 (20.6%) had five or more severe episodes. The most frequent behavioural change in response to hypoglycaemia was insulin dose self-adjustment and the commonest worry was the possibility of becoming emotionally upset during hypoglycaemia. CONCLUSIONS: In a tertiary diabetes clinic in Durban, South Africa, there was a high frequency of hypoglycaemia in patients with T1D and in the majority, at least one severe episode occurred in the 12 months prior to clinic attendance. The results indicate a need for further study and strategies to reduce the frequency and severity of hypoglycaemia.

Non-alcoholic fatty liver disease in Africa: a hidden danger.

There is a dearth of data on the burden and spectrum of non-alcoholic fatty liver disease (NAFLD) in African populations. The limited available information suggests that the prevalence of NAFLD in the general population is lowest for the Africa region. However, this is likely to be an underestimate and also does not take into consideration the long-term impact of rising rates of obesity, type-2 diabetes mellitus (T2DM) and high human immunodeficiency virus infection burden in Africa. A racial disparity in the prevalence of NAFLD has been observed in some studies but remains unexplained. There is an absence of data from population-based studies in Africa and this highlights the need for such studies, to reliably define the health service needs for this region. Screening for NAFLD at a population-based level using ultrasound is perhaps the ideal method for resource-poor settings because of its relative cost-effectiveness. What is required as a priority from Africa, are well-designed epidemiologic studies that screen for NAFLD in the general population as well as high-risk groups such as patients with T2DM or obesity.

Prevalence and characteristics of celiac disease in South African patients with type 1 diabetes mellitus: Results from the Durban Diabetes and Celiac Disease Study.

BACKGROUND AND AIM: The aim of this study was to assess the prevalence and characteristics of celiac disease (CD) in all patients with type 1 diabetes mellitus attending a tertiary adult diabetes clinic in Durban, South Africa. METHODS: This was a cross-sectional observational study that screened 202 patients; of these, 56.4% were African (Black), 31.7% Asian Indian, 4.5% White, and 7.4% mixed race. Demographic data, symptoms, and anthropometry were documented. Blood tests included anti-tissue transglutaminase antibody (tTG), anti-endomysial antibody (EMA), and anti-gliadin antibody (AGA). Endoscopy and duodenal biopsy were performed in patients with celiac antibodies. Diagnosis of CD was based on the modified Marsh classification. RESULTS: Mean age and mean duration of diabetes were 26.4 ± 11.4 and 10.7 ± 9.1 years, respectively. Celiac antibodies were found in 65 (32.2%) patients: EMA 7.4%, tTG immunoglobulin A (IgA) 8.4%, tTG immunoglobulin G 1.9%, AGA IgA 18.3%, and AGA immunoglobulin G 21.8%. Histological evidence of CD was found in 5.9% (n = 12/202): 2.5% were classed as definite CD (Marsh 3) and 3.4% as potential CD (Marsh 1). None of the patients with CD were symptomatic. The sensitivity of AGA IgA, EMA, and tTG IgA antibodies for detecting histologically proven CD was 66.7%, 50.0%, and 41.7%, respectively. CONCLUSION: The prevalence of CD was similar to reports from western countries. No ethnic specific differences were noted. CD was silent in all patients in this study. The sensitivity of EMA and tTG antibodies was poor and merits further evaluation as screening tools for CD in South African patients with type 1 diabetes mellitus.

High prevalence of antithyroid peroxidase and antiparietal cell antibodies among patients with type 1 diabetes mellitus attending a tertiary diabetes centre in South Africa.

OBJECTIVE: Data on the prevalence of autoimmune thyroid disease (AITD) and gastric autoimmunity in type 1 diabetes mellitus (T1DM) in Africa are limited. The aim of this study was to assess the prevalence of antithyroid peroxidase (TPO-A) and antiparietal cell antibody (PCA) in patients with T1DM at a tertiary diabetes clinic in Durban, South Africa. RESEARCH DESIGN AND METHODS: This was a cross-sectional observational study among subjects attending the adult T1DM clinic at Inkosi Albert Luthuli Hospital. Information about history and clinical examination was collected. Blood tests included glutamic acid decarboxylase antibody (GADA), TPO-A, PCA, vitamin B12, folate, ferritin, thyroid stimulating hormone (TSH), free thyroxine, lipids and HbA1c. RESULTS: A total of 202 (M:F, 90:112) patients were recruited. The ethnic composition was African (black) (56.4%; n=114), Indian (31.7%; n=64), white (4.5%; n=9) and coloured (mixed race) (7.4%; n=15). Mean age and mean duration of diabetes were 26.4±11.4 and 10.7±9.1 years, respectively. Mean body mass index was 21.6±6.3 kg/m2. GADA was positive in 63.37% (n=128). The prevalence of TPO-A was 18.9% (n=39) and PCA 8.9% (n=17). The prevalence of overt hypothyroidism, subclinical hypothyroidism and Graves' disease was 10.9%, 2.5% and 1.5%, respectively; vitamin B12 deficiency was noted in 3.5% (n=7) and iron deficiency in 19.3% (n=39). CONCLUSIONS: Among patients with T1DM in this study, there was a high prevalence of coexistent AITD and gastric autoimmunity. Screening for hypothyroidism and thyroid autoimmunity should be undertaken in all patients at initial presentation. However, to assess the feasibility and optimal timing of subsequent testing in the African setting with limited resources, more collaborative research with longitudinal studies is required.

Characteristics and outcome of surgically treated pituitary tumours in South Africa: a single-centre experience.

AIMS: To describe the clinical, biochemical, radiological and histological features and to determine the outcome of all patients with pituitary tumours treated surgically at Inkosi Albert Luthuli Central Hospital (ILACH) in Durban over a 5-year period. RESEARCH DESIGN: Retrospective chart review from 2008 to 2012. Clinical, biochemical and radiological data were collected before and 1 year after surgery. Histopathology findings and perioperative complications were recorded. RESULTS: Seventy patients were included (age 44·8 ± 14·9 years, 55·7% female). Headache (84·1%) and visual disturbances (78·3%) were the predominant presenting symptoms (84·1% and 78·3%). Most tumours were macroadenomas (97·1%). Trans-sphenoidal surgery was employed in the majority (90%). A single procedure was required in 55·7% patients, two procedures in 30% and up to six in others. Complete resection was achieved in only nine patients (12·8%), residual tumour postsurgery was found in 48 (68·6%), and no change in tumour size was found in 13 (18·6%) patients. Additional medical therapy was used in 22 (31·4%) and radiotherapy in 13 (18·6%). On biopsy, the most common pathology was nonfunctional adenoma in 33 (47·1%); 29 (41·4%) were secretory tumours, and 8 (11·4%) were craniopharyngiomas. Overall mortality was 4·3%. The commonest surgical complication was cerebrospinal fluid (CSF) leak (10%; n = 7). New postsurgical pituitary hypofunction occurred in 50 (71·4%) patients. The outcome at 1 year was similar to that on discharge. CONCLUSIONS: Patients presenting to IALCH had large tumours, and complete resection was achieved in a minority. There was a low overall mortality but high rate of postsurgical pituitary hypofunction.

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.

OBJECTIVE: Glycated haemoglobin (HbA1c) is recommended as an additional tool to glucose-based measures (fasting plasma glucose [FPG] and 2-hour plasma glucose [2PG] during oral glucose tolerance test [OGTT]) for the diagnosis of diabetes; however, its use in sub-Saharan African populations is not established. We assessed prevalence estimates and the diagnosis and detection of diabetes based on OGTT, FPG, and HbA1c in an urban black South African population. RESEARCH DESIGN AND METHODS: We conducted a population-based cross-sectional survey using multistage cluster sampling of adults aged ≥18 years in Durban (eThekwini municipality), KwaZulu-Natal. All participants had a 75-g OGTT and HbA1c measurements. Receiver operating characteristic (ROC) analysis was used to assess the overall diagnostic accuracy of HbA1c, using OGTT as the reference, and to determine optimal HbA1c cut-offs. RESULTS: Among 1190 participants (851 women, 92.6% response rate), the age-standardised prevalence of diabetes was 12.9% based on OGTT, 11.9% based on FPG, and 13.1% based on HbA1c. In participants without a previous history of diabetes (n = 1077), using OGTT as the reference, an HbA1c ≥48 mmol/mol (6.5%) detected diabetes with 70.3% sensitivity (95%CI 52.7-87.8) and 98.7% specificity (95%CI 97.9-99.4) (AUC 0.94 [95%CI 0.89-1.00]). Additional analyses suggested the optimal HbA1c cut-off for detection of diabetes in this population was 42 mmol/mol (6.0%) (sensitivity 89.2% [95%CI 78.6-99.8], specificity 92.0% [95%CI: 90.3-93.7]). CONCLUSIONS: In an urban black South African population, we found a high prevalence of diabetes and provide the first evidence for the utility of HbA1c for the diagnosis and detection of diabetes in black Africans in sub-Saharan Africa.

Characteristics, management and outcome of primary hyperparathyroidism in South Africa: a single-centre experience.

INTRODUCTION: Primary hyperparathyroidism (PHPT) is a common endocrine disorder characterised by hypercalcaemia and elevated parathyroid hormone (PTH) levels. However, it remains a relatively underdiagnosed disease in the developing world primarily due to a lack of routine blood chemistry screening. The aim of this analysis was to evaluate the characteristics, management and outcome of patients with PHPT at a tertiary referral clinic in South Africa. METHODS: A retrospective analysis was undertaken on all patients with a diagnosis of PHPT attending the endocrinology clinic at a tertiary referral hospital in Durban, South Africa, between January 2003 and June 2009. Information on clinical presentation, past medical history, biochemistry, radiology, histology and surgical notes were recorded. Patients with multiple endocrine neoplasia were excluded. RESULTS: A total of 28 case records of PHPT were reviewed. The mean age at presentation was 60±14.5 years with a female preponderance (78.6%). The mode of presentation included referral for investigation of an abnormal serum calcium (n: 23), referral from urologist with nephrolithiasis (n: 3) and for investigation of bone disease (n: 2). Symptomatic disease was found in 26 patients (92.9%), including bone pain (75%), fatigue (46.4%) and abdominal pain (32.1%). Mean serum calcium was 3.0+0.39 (normal 2.08-2.65) mmol/L, serum intact PTH 34.7±41.5 (normal 1.2-8.5) pmol/L and serum alkaline phosphatase 206.3±340.2 (normal 53-141) mIU/L. Sestamibi scan was performed on 24 patients and an adenoma was identified in 83.3%. Of the 19 (68%) patients who had parathyroidectomy, an adenoma was identified as the cause in all cases where histology was available (n:18). Surgery was successful in 18 patients with only one patient requiring repeat parathyroidectomy for persistent hypercalcaemia. Postoperative hypocalcaemia developed in eight patients (42.1%) including four patients who required intravenous calcium infusion for symptomatic hypocalcaemia. CONCLUSIONS: PHPT is a treatable disorder with good surgical success. Asymptomatic disease was uncommon in this group of patients. This is compatible with the symptomatic pattern of presentation reported in other developing countries.

The prevalence of metabolic syndrome and determination of the optimal waist circumference cutoff points in a rural South african community.

OBJECTIVE: To determine the prevalence of metabolic syndrome and to define optimal ethnic-specific waist-circumference cutoff points in a rural South African black community. RESEARCH DESIGN AND METHODS: This was a cross-sectional survey conducted by random-cluster sampling of adults aged >15 years. Participants had demographic, anthropometric, and biochemical measurements taken, including a 75-g oral glucose tolerance test. Metabolic syndrome was defined using the 2009 Joint Interim Statement (JIS) definition. RESULTS: Of 947 subjects (758 women) studied, the age-adjusted prevalence of metabolic syndrome was 22.1%, with a higher prevalence in women (25.0%) than in men (10.5%). Peak prevalence was in the oldest age-group (≥65 years) in women (44.2%) and in the 45- to 54-year age-group in men (25.0%). The optimal waist circumference cutoff point to predict the presence of at least two other components of the metabolic syndrome was 86 cm for men and 92 cm for women. The crude prevalence of metabolic syndrome was higher with the JIS definition (26.5%) than with the International Diabetes Federation (IDF) (23.3%) or the modified Third Report of the National Cholesterol Education Program Adult Treatment Panel (ATPIII) (18.5%) criteria; there was very good agreement with the IDF definition (κ = 0.90 [95% CI 0.87-0.94]) and good concordance with ATPIII criteria (0.77 [0.72-0.82]). CONCLUSIONS: There is a high prevalence of metabolic syndrome, especially in women, suggesting that this community, unlike other rural communities in Africa, already has entered the epidemic of metabolic syndrome. Waist circumference cutoff points differ from those currently recommended for Africans.

Diabetes and other disorders of glycemia in a rural South African community: prevalence and associated risk factors.

OBJECTIVE: The purpose of this study was to determine the prevalence of diabetes, impaired glucose tolerance (IGT), impaired fasting glycemia (IFG), and associated risk factors in a rural South African black community. RESEARCH DESIGN AND METHODS: This was a cross-sectional survey conducted by random cluster sampling of adults aged >15 years. Participants had a 75-g oral glucose tolerance test using the 1998 World Health Organization criteria for disorders of glycemia. RESULTS: Of 1,300 subjects selected, 1,025 subjects (815 women) participated (response rate 78.9%). The overall age-adjusted prevalence of diabetes was 3.9%, IGT 4.8%, and IFG 1.5%. The prevalence was similar in men and women for diabetes (men 3.5%; women 3.9%) and IGT (men 4.6%; women 4.7%) but higher in men for IFG (men 4.0%; women 0.8%). The prevalence of diabetes and IGT increased with age both in men and women, with peak prevalence in the 55- to 64-year age-group for diabetes and in the >or=65-year age-group for IGT. Of the cases of diabetes, 84.8% were discovered during the survey. In multivariate analysis, the significant independent risk factors associated with diabetes included family history (odds ratio 3.5), alcohol ingestion (2.8), waist circumference (1.1), systolic blood pressure (1.0), serum triglycerides (2.3), and total cholesterol (1.8); hip circumference was protective (0.9). CONCLUSIONS: There is a moderate prevalence of diabetes and a high prevalence of total disorders of glycemia, which suggests that this community, unlike other rural communities in Africa, is well into an epidemic of glucose intolerance. There is a low proportion of known diabetes and a significant association with potentially modifiable risk factors.

Cost-effective management of diabetes mellitus.

Diabetes is one of the most common noncommunicable diseases (NCD) globally and a leading cause of death in many countries; the global epidemic of type 2 diabetes will most affect the developing world. The burden of diabetes is related to its chronic complications, both the specific microvascular and the nonspecific macrovascular (atherosclerosis), making diabetes one of the leading causes of death in some countries and an enormous financial burden. The costs of diabetes care, both direct and indirect, are high. Single and multiple risk-factor intervention studies have provided evidence that targeting hyperglycemia and other nonglycemic risk factors reduces the risk of chronic complications; most national guidelines recommend intensified, multitargeted intervention of known modifiable risk factors. The aim in management is optimal control, both glycemic and non-glycemic (blood pressure, lipid and weight control). Management strategies for hyperglycemia include standard methods and individualized options. Given the complexities of the therapeutic choices (classes/agents) and regimens and on the basis of proven benefit, long familiarity, known side-effects, and reduced cost of sulfonylureas, biguanides, and insulin, one should start with standard methods. Despite the evidence for benefit of glycemic control, wide therapeutic choices and regimens and clearer targets for control, glycemic control is far from ideal. The cost-effectiveness of interventions to reduce the burden of diabetes-related complications compares favorably with that of other accepted uses of healthcare resources and provides convincing economic rationale for improving standards of care for patients with type 2 diabetes.

Diabetes in Africa. Epidemiology of type 1 and type 2 diabetes in Africa.

Until recently, there was a paucity of data on the epidemiology of diabetes mellitus in Africa. Over the past decade, information on the prevalence of type 2 diabetes has increased, albeit still limited, but there is still a lack of adequate data on type 1 diabetes in sub-Saharan Africa (SSA). For type 2 diabetes, although the prevalence is low in some rural populations, moderate and even high rates have been reported from other countries. In low diabetes prevalence populations, the moderate to high rates of impaired glucose tolerance is a possible indicator of the early stage of a diabetes epidemic. Diabetes prevalence is higher in urban, migrant and African-origin populations living abroad. There is evidence for a significant association with preventable and modifiable risk factors viz. adiposity, known diabetes, physical activity; but a dearth of data on the impact of dietary and genetic factors. For type 1 diabetes, the limited available data suggest that in SSA the frequency is low and that age of onset occurs later than in the western world. There is evidence for the role of genetic and immunological factors in its pathogenesis. The impact of HIV/AIDS on projected estimates for diabetes prevalence in Africa needs to be established.