Detection of impaired glucose tolerance and undiagnosed type 2 diabetes in UK South Asians: an effective screening strategy

A meta-analysis of diabetes risk prediction models applied to prediabetes screening

AIM

To provide a systematic overview of diabetes risk prediction models used for prediabetes screening to promote primary prevention of diabetes.

METHODS

The Cochrane, PubMed, Embase, Web of Science and China National Knowledge Infrastructure (CNKI) databases were searched for a comprehensive search period of 30 August 30, 2023, and studies involving diabetes prediction models for screening prediabetes risk were included in the search. The Quality Assessment Checklist for Diagnostic Studies (QUADAS-2) tool was used for risk of bias assessment and Stata and R software were used to pool model effect sizes.

RESULTS

A total of 29 375 articles were screened, and finally 20 models from 24 studies were included in the systematic review. The most common predictors were age, body mass index, family history of diabetes, history of hypertension, and physical activity. Regarding the indicators of model prediction performance, discrimination and calibration were only reported in 79.2% and 4.2% of studies, respectively, resulting in significant heterogeneity in model prediction results, which may be related to differences between model predictor combinations and lack of important methodological information.

CONCLUSIONS

Numerous models are used to predict diabetes, and as there is an association between prediabetes and diabetes, researchers have also used such models for screening the prediabetic population. Although it is a new clinical practice to explore, differences in glycaemic metabolic profiles, potential complications, and methods of intervention between the two populations cannot be ignored, and such differences have led to poor validity and accuracy of the models. Therefore, there is no recommended optimal model, and it is not recommended to use existing models for risk identification in alternative populations; future studies should focus on improving the clinical relevance and predictive performance of existing models.

Diabetes in the Kokan region of India

BACKGROUND

BKL Walawalkar Hospital is situated near the village of Dervan in the Kokan region of the state of Maharashtra in India. A survey of 2200 surrounding villages showed 51.8% adults had body mass index (BMI) below <18.5 kg/m² and only 4.5% were overweight. A survey of 11521 adolescent girls from rural schools showed 64% prevalence of thinness. In the same region, government survey reported the prevalence of diabetes around 7%, and 70% prevalence of leanness. This reinforced the fact that the overall population of Kokan is lean. Hence, we decided to investigate body composition of diabetic people from our hospital clinic by carrying out a clinic-based case control study.

AIM

To study body composition of diabetics in a rural clinic of Kokan.

METHODS

In a case-control study, 168 type 2 diabetic patients (102 men) attending the outpatient department at a rural hospital and 144 non-diabetic controls (68 men) in the Chiplun area of the Kokan region were recruited. History of diabetes (age of onset, duration), anthropometric measurements (height, weight, waist and hip circumference) were recorded. Body composition was measured by bioimpedance using the TANITA analyzer.

RESULTS

More than 45% of diabetic subjects had a 1^st degree family history of diabetes, and more than 50% had macrovascular complications. The average BMI in diabetic subjects was 24.3 kg/m². According to World Health Organization standards, prevalence of underweight was 8% and that of normal BMI was around 50%. Underweight and normal diabetic subjects (men as well as women) had significantly lower body fat percentage, higher muscle mass percentage, lower visceral fat and lower basal metabolic rate when compared to their overweight counterparts.

CONCLUSION

The diabetic population in Kokan has near normal body composition, and BMI has considerable limitations in assessing body composition and it also lacks sensitivity for assessing risk for diabetes in this population. High prevalence of family history of diabetes may point towards genetic predisposition. Leanness is an inherent characteristic of this population and its metabolic significance needs further investigations with a larger sample size.

The effect of vildagliptin relative to sulfonylurea as dual therapy with metformin (or as monotherapy) in Muslim patients with type 2 diabetes fasting during Ramadan in the Middle East: the VIRTUE study

OBJECTIVE

To assess the effect of vildagliptin relative to sulfonylurea (SU) on hypoglycemic events, in Muslim patients from the Middle East with type 2 diabetes who fast during Ramadan. The primary endpoint was the proportion of patients with at least one hypoglycemic event (HE) during the fasting period. Secondary endpoints included change in weight, HbA1c levels, treatment adherence and overall safety.

DESIGN AND METHODS

This multicenter, prospective, observational cohort study enrolled Muslim adult T2DM patients from Middle Eastern countries who received treatment with vildagliptin or SU as add on to metformin or monotherapy. During a ∼16 week observation period, data was collected up to 6 weeks before and 6 weeks after Ramadan fasting.

RESULTS

A total of 584 patients from the Middle East enrolled in the study; 308 patients received vildagliptin and 265 received SU. Significantly fewer vildagliptin patients reported at least one HE (3.7% vildagliptin vs. 25.5% SU; p < .001). No grade 2 HEs were reported in vildagliptin patients versus two in SU patients (p = .128). Mean change in HbA1c at the end of study showed -0.18% between treatment difference in favor of vildagliptin, p = .001. Mean body weight change at the end of study showed -0.68 kg between treatment difference in favor of vildagliptin, p < .001. Treatment exposure and adherence were high and similar in both cohorts. There were 4.3% adverse events reported in vildagliptin compared to 25.3% in the SU cohort, with hypoglycemia being the most experienced event in both cohorts.

LIMITATIONS

Being observational and not mandating HE confirmation with blood glucose measurement (though it was done in a large number of patients) were key limitations.

CONCLUSION

Anti-hyperglycemic treatment with vildagliptin led to significantly fewer hypoglycemia events compared to sulfonylurea treatment among Muslim diabetic patients who fast during Ramadan. Good glycemic control, weight control and safety results supported this outcome.

A community faith centre based screening and educational intervention to reduce the risk of type 2 diabetes: A feasibility study

AIMS

People of South Asian origin experience higher rates of diabetes and complications of diabetes compared to white Europeans. Therefore, it is important to identify those with undiagnosed diabetes and those at high risk of developing diabetes, in order to intervene with lifestyle intervention to reduce risk and prevent complications. We conducted a study to assess the feasibility of delivering a faith centre based pathway for screening and referral to group education for high risk individuals to increase screening uptake and reduce diabetes risk.

METHODS

Opportunistic screening and early intervention strategy for people at risk of diabetes and cardiovascular disease in local faith centres. The screening consisted of a diabetes risk assessment tool and a near patient test for HbA1c. Participants found to be at high risk of diabetes (HbA1c 6-6.4%/42-46mmol/mol) were offered a 'Walking Away from Diabetes' group educational intervention aimed at increasing exercise levels and reducing diabetes risk.

RESULTS

252 participants were screened during four screening events. 202 participants (80.2%) gave consent for their data to be included in the analysis. 72.4% of participants were found to have a high diabetes risk score. 32 participants (15.8%) had a HbA1c result (6-6.4%/42-46mmol/mol). Eight participants (4.0%) had a (HbA1c ⩾6.5%/⩾47mmol/mol). Of those eligible for the diabetes prevention education programme, 18 participants (56.3%) attended.

CONCLUSIONS

This study confirms that screening followed by group education within faith centre settings is feasible and acceptable to participants. The strategies chosen were effective in achieving a high screening yield and high uptake of group education.

Predictive modeling for incident and prevalent diabetes risk evaluation

With half of individuals with diabetes undiagnosed worldwide and a projected 55% increase of the population with diabetes by 2035, the identification of undiagnosed and high-risk individuals is imperative. Multivariable diabetes risk prediction models have gained popularity during the past two decades. These have been shown to predict incident or prevalent diabetes through a simple and affordable risk scoring system accurately. Their development requires cohort or cross-sectional type studies with a variable combination, number and definition of included risk factors, with their performance chiefly measured by discrimination and calibration. Models can be used in clinical and public health settings. However, the impact of their use on outcomes in real-world settings needs to be evaluated before widespread implementation.

Reporting and handling of missing data in predictive research for prevalent undiagnosed type 2 diabetes mellitus: a systematic review

Missing values are common in health research and omitting participants with missing data often leads to loss of statistical power, biased estimates and, consequently, inaccurate inferences. We critically reviewed the challenges posed by missing data in medical research and approaches to address them. To achieve this more efficiently, these issues were analyzed and illustrated through a systematic review on the reporting of missing data and imputation methods (prediction of missing values through relationships within and between variables) undertaken in risk prediction studies of undiagnosed diabetes. Prevalent diabetes risk models were selected based on a recent comprehensive systematic review, supplemented by an updated search of English-language studies published between 1997 and 2014. Reporting of missing data has been limited in studies of prevalent diabetes prediction. Of the 48 articles identified, 62.5% (n = 30) did not report any information on missing data or handling techniques. In 21 (43.8%) studies, researchers opted out of imputation, completing case-wise deletion of participants missing any predictor values. Although imputation methods are encouraged to handle missing data and ensure the accuracy of inferences, this has seldom been the case in studies of diabetes risk prediction. Hence, we elaborated on the various types and patterns of missing data, the limitations of case-wise deletion and state-of the-art methods of imputations and their challenges. This review highlights the inexperience or disregard of investigators of the effect of missing data in risk prediction research. Formal guidelines may enhance the reporting and appropriate handling of missing data in scientific journals.

Evaluation of the role of enteral nutrition in managing patients with diabetes: a systematic review

The aim of this systematic review is to evaluate the role of enteral nutrition in managing patients with diabetes on enteral feed. The prevalence of diabetes is on the increase in the UK and globally partly due to lack of physical activities, poor dietary regimes and genetic susceptibility. The development of diabetes often leads to complications such as stroke, which may require enteral nutritional support. The provision of enteral feeds comes with its complications including hyperglycaemia which if not managed can have profound consequences for the patients in terms of clinical outcomes. Therefore, it is essential to develop strategies for managing patients with diabetes on enteral feed with respect to the type and composition of the feed. This is a systematic review of published peer reviewed articles. EBSCOhost Research, PubMed and SwetsWise databases were searched. Reference lists of identified articles were reviewed. Randomised controlled trials comparing enteral nutrition diabetes specific formulas with standard formulas were included. The studies which compared diabetes specific formulas (DSF) with standard formulas showed that DSF was more effective in controlling glucose profiles including postprandial glucose, HbA1c and insulinemic response. The use of DSF appears to be effective in managing patients with diabetes on enteral feed compared with standard feed.

Design and baseline characteristics of the PODOSA (Prevention of Diabetes & Obesity in South Asians) trial: a cluster, randomised lifestyle intervention in Indian and Pakistani adults with impaired glycaemia at high risk of developing type 2 diabetes

OBJECTIVES

To describe the design and baseline population characteristics of an adapted lifestyle intervention trial aimed at reducing weight and increasing physical activity in people of Indian and Pakistani origin at high risk of developing type 2 diabetes.

DESIGN

Cluster, randomised controlled trial.

SETTING

Community-based in Edinburgh and Glasgow, Scotland, UK.

PARTICIPANTS

156 families, comprising 171 people with impaired glycaemia, and waist sizes ≥90 cm (men) and ≥80 cm (women), plus 124 family volunteers.

INTERVENTIONS

Families were randomised into either an intensive intervention of 15 dietitian visits providing lifestyle advice, or a light (control) intervention of four visits, over a period of 3 years.

OUTCOME MEASURES

The primary outcome is a change in mean weight between baseline and 3 years. Secondary outcomes are changes in waist, hip, body mass index, plasma blood glucose and physical activity. The cost of the intervention will be measured. Qualitative work will seek to understand factors that motivated participation and retention in the trial and families' experience of adhering to the interventions.

RESULTS

Between July 2007 and October 2009, 171 people with impaired glycaemia, along with 124 family volunteers, were randomised. In total, 95% (171/196) of eligible participants agreed to proceed to the 3-year trial. Only 13 of the 156 families contained more than one recruit with impaired glycaemia. We have recruited sufficient participants to undertake an adequately powered trial to detect a mean difference in weight of 2.5 kg between the intensive and light intervention groups at the 5% significance level. Over half the families include family volunteers. The main participants have a mean age of 52 years and 64% are women.

CONCLUSIONS

Prevention of Diabetes & Obesity in South Asians (PODOSA) is one of the first community-based, randomised lifestyle intervention trials in a UK South Asian population. The main trial results will be submitted for publication during 2013.

TRIAL REGISTRATION

Current controlled trials ISRCTN25729565 (http://www.controlled-trials.com/isrctn/).

Risk scores based on self-reported or available clinical data to detect undiagnosed type 2 diabetes: a systematic review

OBJECTIVE

To systematically review published primary research on the development or validation of risk scores that require only self-reported or available clinical data to identify undiagnosed Type 2 Diabetes Mellitus (T2DM).

METHODS

A systematic literature search of Medline and EMBASE was conducted until January 2011. Studies focusing on the development or validation of risk scores to identify undiagnosed T2DM were included. Risk scores to predict future risk of T2DM were excluded.

RESULTS

Thirty-one studies were included; 17 developed a new risk score, 14 validated existing scores. Twenty-six studies were conducted in high-income countries. Age and measures of body mass/fat distribution were the most commonly used predictor variables. Studies developing new scores performed better than validation studies, with 11 reporting an AUC of >0.80 compared to one validation study. Fourteen validation studies reported sensitivities of <80%. The performance of scores did not differ by the number of variables included or the country setting.

CONCLUSIONS

There is a proliferation of newly developed risk scores using similar variables, which sometimes perform poorly upon external validation. Future research should explore the recalibration, validation and applicability of existing scores to other settings, particularly in low/middle income countries, and on the utility of scores to improve diabetes-related outcomes.

Survey of diabetes risk assessment tools: concepts, structure and performance

The objective of this study is to review the effectiveness and limitations of existing diabetes risk screening tools to assess the need for further developing of such tools. An electronic search of the EMBASE, MEDLINE, and Cochrane library supplemented by a manual search was performed from 1995-2010. The search retrieved a total of 2168 articles reporting diabetes risk assessment tools which, after culling, produced 41 tools developed in 22 countries, with the majority (n = 26) developed in North America and Europe. All are short questionnaires of 2-16 questions incorporating common variables including age, gender, waist circumference, BMI, family history of diabetes, history of hypertension or antihypertensive medications. While scoring format and cut-offs point are diverse between questionnaires, overall accuracy value range of 40-97%, 24-86% and 62-87% were reported for sensitivity, specificity and receiver operating characteristic curve respectively. In summary, there is a trend of increasing availability of diabetes prediction tools with the existing risk assessment tools being generally a short questionnaire aiming for ease of use in clinical practice. The overall performance of existing tools showed moderate to high accuracy in their predictive performance. However, further detailed comparison of existing questionnaires is needed to evaluate whether they can serve adequately as diabetes risk assessment tool in clinical practice.

Prevalence, risk factors and complications associated with type 2 diabetes in migrant South Asians

It is estimated that type 2 diabetes (T2D) currently affects about 246 million people worldwide, with South Asians, especially Indians, having both the largest number of cases and the fastest growing prevalence. South Asian ethnicity has been identified as a major risk factor for the development of T2D with central adiposity, insulin resistance and an unfavourable lipid profile being identified as predominant signals of alarm. Leading databases, including Web of Science, Medline, PubMed and Science Direct, were consulted and manual searches were conducted for cited references in leading diabetes-related journals. In all, 152 articles were included for the final assessment reported in this review. Genetic predisposition, central adiposity and unfavourable lifestyle, including physical inactivity and an unhealthy diet, were associated with the prevalence of T2D in migrant South Asians. 'Westernization', acculturation, socio-economic factors and lack of knowledge about the disease have also been identified as contributors to the development of T2D in this population. Higher prevalence of T2D in migrant South Asians may not be entirely attributed to genetic predisposition; hence, ethnicity and associated modifiable risk factors need further investigation. Preventive measures and appropriate interventions are currently limited by the lack of ethnic-specific cut-off points for anthropometric and biological markers, as well as by the absence of reliable methods for dietary and physical activity assessment. This article describes the prevalence rate, risk factors and complications associated with T2D in migrant South Asians living in different countries.

Recruiting South Asians to a lifestyle intervention trial: experiences and lessons from PODOSA (Prevention of Diabetes & Obesity in South Asians)

Background

Despite the growing emphasis on the inclusion of ethnic minority patients in research, there is little published on the recruitment of these populations especially to randomised, community based, lifestyle intervention trials in the UK.

Methods

We share our experience of recruitment to screening in the PODOSA (Prevention of Diabetes and Obesity in South Asians) trial, which screened 1319 recruits (target 1800) for trial eligibility. A multi-pronged recruitment approach was used. Enrolment via the National Health Service included direct referrals from health care professionals and written invitations via general practices. Recruitment within the community was carried out by both the research team and through our partnerships with local South Asian groups and organisations. Participants were encouraged to refer friends and family throughout the recruitment period.

Results

Health care professionals referred only 55 potential participants. The response to written invitations via general practitioners was 5.2%, lower than reported in other general populations. Community orientated, personal approaches for recruitment were comparatively effective yielding 1728 referrals (82%) to the screening stage.

Conclusions

The PODOSA experience shows that a community orientated, personal approach for recruiting South Asian ethnic minority populations can be successful in a trial setting. We recommend that consideration is given to cover recruitment costs associated with community engagement and other personalised approaches. Researchers should consider prioritising approaches that minimise interference with professionals' work and, particularly in the current economic climate, keep costs to a minimum. The lessons learned in PODOSA should contribute to future community based trials in South Asians.

Trial Registration

Current Controlled Trials ISRCTN25729565

Comparison of the dipeptidyl peptidase-4 inhibitor vildagliptin and the sulphonylurea gliclazide in combination with metformin, in Muslim patients with type 2 diabetes mellitus fasting during Ramadan: results of the VECTOR study

OBJECTIVE

To compare the incidence of hypoglycaemic events (HEs) in a real-world setting in Muslim patients with type 2 diabetes mellitus fasting during Ramadan.

RESEARCH DESIGN AND METHODS

We performed a ≤16-week prospective, non-interventional, two-cohort study. Data were collected 1-6 weeks before and ≤6 weeks after fasting. Patients were enrolled who had been receiving vildagliptin (50 mg twice daily) or sulphonylurea (SU) as add-on to metformin at least 4 weeks prior to fasting.

MAIN OUTCOME MEASURES

The primary efficacy endpoint was incidence of HEs during the Ramadan fast. Changes in glycated haemoglobin (HbA(1c)) and body weight, as well as adherence to treatment, were also assessed.

RESULTS

Seventy-two patients were enrolled (vildagliptin, n = 30; SU, n = 41; no treatment, n = 1), of whom 23 (76.7%) and 36 (87.8%), respectively, completed the study. With vildagliptin, there were no HEs or severe HEs, compared with 34 HEs (15 patients, 41.7%) and one severe (grade 2) HE with SU. The mean between-group difference in the proportion who experienced at least one HE was -41.7% (95%CI -57.8%, -25.6%), p = 0.0002. Vildagliptin lowered mean HbA(1c) from 7.6% (SD 0.9%) at baseline to 7.2% (SD 0.7%) post-Ramadan, whereas SU had no effect (7.2% [SD 0.6%] vs 7.3% [SD 0.7%]; mean between-group difference -0.5% [95% CI -0.9%, -0.1%], p = 0.0262). The mean number of missed doses was markedly lower with vildagliptin (0.2 [SD 0.8] vs 7.6 [SD 14.9]; mean between-group difference -7.4 [95% CI -13.7, -1.20] doses; p = 0.0204). Body weight remained unchanged in both groups.

CONCLUSION

Vildagliptin caused no hypoglycaemia, was well adhered to and improved HbA(1c), making it a suitable treatment option for managing fasting. Study limitations are the sample size and the lack of diet and exercise data. When extrapolated to the global Muslim population with a similar clinical background, these findings could have considerable public health and clinical implications.

Screening for type 2 diabetes and dysglycemia

Type 2 diabetes mellitus (T2DM) and dysglycemia (impaired glucose tolerance and/or impaired fasting glucose) are increasingly contributing to the global burden of diseases. The authors reviewed the published literature to critically evaluate the evidence on screening for both conditions and to identify the gaps in current understanding. Acceptable, relatively simple, and accurate tools can be used to screen for both T2DM and dysglycemia. Lifestyle modification and/or medication (e.g., metformin) are cost-effective in reducing the incidence of T2DM. However, their application is not yet routine practice. It is unclear whether diabetes-prevention strategies, which influence cardiovascular risk favorably, will also prevent diabetic vascular complications. Cardioprotective therapies, which are cost-effective in preventing complications in conventionally diagnosed T2DM, can be used in screen-detected diabetes, but the magnitude of their effects is unknown. Economic modeling suggests that screening for both T2DM and dysglycemia may be cost-effective, although empirical data on tangible benefits in preventing complications or death are lacking. Screening for T2DM is psychologically unharmful, but the specific impact of attributing the label of dysglycemia remains uncertain. Addressing these gaps will inform the development of a screening policy for T2DM and dysglycemia within a holistic diabetes prevention and control framework combining secondary and high-risk primary prevention strategies.

Sitting time and waist circumference are associated with glycemia in U.K. South Asians: data from 1,228 adults screened for the PODOSA trial

OBJECTIVE

To investigate the independent contributions of waist circumference, physical activity, and sedentary behavior on glycemia in South Asians living in Scotland.

RESEARCH DESIGN AND METHODS

Participants were 1,228 (523 men and 705 women) adults of Indian or Pakistani origin screened for the Prevention of Type 2 Diabetes and Obesity in South Asians (PODOSA) trial. All undertook an oral glucose tolerance test, had physical activity and sitting time assessed by International Physical Activity Questionnaire, and had waist circumference measured.

RESULTS

Mean ± SD age and waist circumference were 49.8 ± 10.1 years and 99.2 ± 10.2 cm, respectively. One hundred ninety-one participants had impaired fasting glycemia or impaired glucose tolerance, and 97 had possible type 2 diabetes. In multivariate regression analysis, age (0.012 mmol ⋅ L⁻¹ ⋅ year⁻¹ [95% CI 0.006-0.017]) and waist circumference (0.018 mmol ⋅ L⁻¹ ⋅ cm⁻¹ [0.012-0.024]) were significantly independently associated with fasting glucose concentration, and age (0.032 mmol ⋅ L⁻¹ ⋅ year⁻¹ [0.016-0.049]), waist (0.057 mmol ⋅ L⁻¹ ⋅ cm⁻¹ [0.040-0.074]), and sitting time (0.097 mmol ⋅ L⁻¹ ⋅ h⁻¹ ⋅ day⁻¹ [0.036-0.158]) were significantly independently associated with 2-h glucose concentration. Vigorous activity time had a borderline significant association with 2-h glucose concentration (-0.819 mmol ⋅ L⁻¹ ⋅ h⁻¹ ⋅ day⁻¹ [-1.672 to 0.034]) in the multivariate model.

CONCLUSIONS

These data highlight an important relationship between sitting time and 2-h glucose levels in U.K. South Asians, independent of physical activity and waist circumference. Although the data are cross-sectional and thus do not permit firm conclusions about causality to be drawn, the results suggest that further study investigating the effects of sitting time on glycemia and other aspects of metabolic risk in South Asian populations is warranted.