Glucose challenge test screening for prediabetes and early diabetes

AIMS

To test the hypothesis that a 50-g oral glucose challenge test with 1-h glucose measurement would have superior performance compared with other opportunistic screening methods.

METHODS

In this prospective study in a Veterans Health Administration primary care clinic, the following test performances, measured by area under receiver-operating characteristic curves, were compared: 50-g oral glucose challenge test; random glucose; and HbA_1c level, using a 75-g oral glucose tolerance test as the 'gold standard'.

RESULTS

The study population was comprised of 1535 people (mean age 56 years, BMI 30.3 kg/m² , 94% men, 74% black). By oral glucose tolerance test criteria, diabetes was present in 10% and high-risk prediabetes was present in 22% of participants. The plasma glucose challenge test provided area under receiver-operating characteristic curves of 0.85 (95% CI 0.78-0.91) to detect diabetes and 0.76 (95% CI 0.72-0.80) to detect high-risk dysglycaemia (diabetes or high-risk prediabetes), while area under receiver-operating characteristic curves for the capillary glucose challenge test were 0.82 (95% CI 0.75-0.89) and 0.73 (95% CI 0.69-0.77) for diabetes and high-risk dysglycaemia, respectively. Random glucose performed less well [plasma: 0.76 (95% CI 0.69-0.82) and 0.66 (95% CI 0.62-0.71), respectively; capillary: 0.72 (95% CI 0.65-0.80) and 0.64 (95% CI 0.59-0.68), respectively], and HbA_1c performed even less well [0.67 (95% CI 0.57-0.76) and 0.63 (95% CI 0.58-0.68), respectively]. The cost of identifying one case of high-risk dysglycaemia with a plasma glucose challenge test would be $42 from a Veterans Health Administration perspective, and $55 from a US Medicare perspective.

CONCLUSIONS

Glucose challenge test screening, followed, if abnormal, by an oral glucose tolerance test, would be convenient and more accurate than other opportunistic tests. Use of glucose challenge test screening could improve management by permitting earlier therapy.

A new predictive tool for the early risk assessment of gestational diabetes mellitus

AIMS

The Italian National Institute of Health has recently introduced a selective screening based on the risk profile of pregnant women, which while recommending against screening of women at low risk (LR) for GDM, it recommends an early test for women at high risk (HR) for GDM. Herein, we assessed the accuracy and cost-effectiveness of this screening and developed a new index that improves these requirements.

METHODS

We retrospectively enrolled 3974 pregnant women. GDM was diagnosed with a 2h 75-g OGTT at 16-18 weeks (early test) or 24-28 weeks of gestation, according to the IADPSG guidelines.

RESULTS

55.6% of HR women had GDM, although only 38.4% underwent early screening. Among 2654 women at medium risk, 20.9% had GDM; paradoxically, among 770 LR women, that would not have been screened, 26.6% received a GDM diagnosis. Based on these unsatisfactory results, we elaborated the Capula's index, that reduced both screening tests (p<0.001) and potentially undetected GDM cases (p<0.001), and corrected the paradoxical prevalence estimates of GDM obtained with the current Italian guidelines. Also, Capula's index improved correlation of GDM risk profile with obstetric and neonatal adverse events.

CONCLUSIONS

Capula's index improves accuracy of selective screening for GDM.

Use of capillary blood glucose for screening for gestational diabetes mellitus in resource-constrained settings

AIMS

The aim of the study was to evaluate usefulness of capillary blood glucose (CBG) for diagnosis of gestational diabetes mellitus (GDM) in resource-constrained settings where venous plasma glucose (VPG) estimations may be impossible.

METHODS

Consecutive pregnant women (n = 1031) attending antenatal clinics in southern India underwent 75-g oral glucose tolerance test (OGTT). Fasting, 1- and 2-h VPG (AU2700 Beckman, Fullerton, CA) and CBG (One Touch Ultra-II, LifeScan) were simultaneously measured. Sensitivity and specificity were estimated for different CBG cut points using the International Association of Diabetes in Pregnancy Study Groups (IADPSG) criteria for the diagnosis of GDM as gold standard. Bland-Altman plots were drawn to look at the agreement between CBG and VPG. Correlation and regression equation analysis were also derived for CBG values.

RESULTS

Pearson's correlation between VPG and CBG for fasting was r = 0.433 [intraclass correlation coefficient (ICC) = 0.596, p < 0.001], for 1H, it was r = 0.653 (ICC = 0.776, p < 0.001), and for 2H, r = 0.784 (ICC = 0.834, p < 0.001). Comparing a single CBG 2-h cut point of 140 mg/dl (7.8 mmol/l) with the IADPSG criteria, the sensitivity and specificity were 62.3 and 80.7 %, respectively. If CBG cut points of 120 mg/dl (6.6 mmol/l) or 110 mg/dl (6.1 mmol/l) were used, the sensitivity improves to 78.3 and 92.5 %, respectively.

CONCLUSIONS

In settings where VPG estimations are not possible, CBG can be used as an initial screening test for GDM, using lower 2H CBG cut points to maximize the sensitivity. Those who screen positive can be referred to higher centers for definitive testing, using VPG.

Cost-effectiveness of the New Zealand diabetes in pregnancy guideline screening recommendations

OBJECTIVE

To compare the cost-effectiveness of 2 possible screening strategies for gestational diabetes mellitus (GDM) from the perspective of the New Zealand health system, developed as part of a gestational diabetes guideline.

DESIGN

A decision analytic model was built comparing 2-step screening (glycated haemoglobin (HbA1c) test at first booking and a 2 h 75 g oral glucose tolerance test (OGTT) as a single test at 24-28 weeks) with 3-step screening (HbA1c test at first booking and a 1 h glucose challenge test (GCT) followed by a 2 h 75 g OGTT when indicated from 24-28 weeks) using a 9-month time horizon.

SETTING

A hypothetical cohort of 62,000 pregnant women in New Zealand.

METHODS

Probabilities, costs and benefits were derived from the literature, and supplementary data was obtained from National Women's Annual Clinical Reports. Main outcome measures, screening and treatment costs (NZ$2013) and effect on health outcomes (incidence of complications).

RESULTS

The total cost for both strategies under baseline assumptions shows that the 2-step screening strategy would cost NZ$1.38 m more than the 3-step screening strategy overall. The additional cost per case detected was NZ$12,460 per case. The model found that the 2-step screening strategy identifies 12 more women with diabetes and 111 more women with GDM when compared against the 3-step screening strategy. We assessed the effect of changing the sensitivity and specificity of the OGTT. The baseline model assumed that the 2 h 75 g OGTT has a sensitivity and specificity of 95%. The 2-step strategy becomes more cost-effective when the diagnostic accuracy measures are improved.

CONCLUSIONS

Adopting a 2-step strategy would moderately increase the number of GDM cases detected at the same time as moderately increasing the number of women with false negatives at a significant cost to the health system. Further evidence on the benefits of the 2 different approaches would be welcome.

Optimal cut-off points of fasting plasma glucose for two-step strategy in estimating prevalence and screening undiagnosed diabetes and pre-diabetes in Harbin, China

To identify optimal cut-off points of fasting plasma glucose (FPG) for two-step strategy in screening abnormal glucose metabolism and estimating prevalence in general Chinese population. A population-based cross-sectional study was conducted on 7913 people aged 20 to 74 years in Harbin. Diabetes and pre-diabetes were determined by fasting and 2 hour post-load glucose from the oral glucose tolerance test in all participants. Screening potential of FPG, cost per case identified by two-step strategy, and optimal FPG cut-off points were described. The prevalence of diabetes was 12.7%, of which 65.2% was undiagnosed. Twelve percent or 9.0% of participants were diagnosed with pre-diabetes using 2003 ADA criteria or 1999 WHO criteria, respectively. The optimal FPG cut-off points for two-step strategy were 5.6 mmol/l for previously undiagnosed diabetes (area under the receiver-operating characteristic curve of FPG 0.93; sensitivity 82.0%; cost per case identified by two-step strategy ¥261), 5.3 mmol/l for both diabetes and pre-diabetes or pre-diabetes alone using 2003 ADA criteria (0.89 or 0.85; 72.4% or 62.9%; ¥110 or ¥258), 5.0 mmol/l for pre-diabetes using 1999 WHO criteria (0.78; 66.8%; ¥399), and 4.9 mmol/l for IGT alone (0.74; 62.2%; ¥502). Using the two-step strategy, the underestimates of prevalence reduced to nearly 38% for pre-diabetes or 18.7% for undiagnosed diabetes, respectively. Approximately a quarter of the general population in Harbin was in hyperglycemic condition. Using optimal FPG cut-off points for two-step strategy in Chinese population may be more effective and less costly for reducing the missed diagnosis of hyperglycemic condition.

Screening uptake rates and the clinical and cost effectiveness of screening for gestational diabetes mellitus in primary versus secondary care: study protocol for a randomised controlled trial

BACKGROUND

The risks associated with gestational diabetes mellitus (GDM) are well recognized, and there is increasing evidence to support treatment of the condition. However, clear guidance on the ideal approach to screening for GDM is lacking. Professional groups continue to debate whether selective screening (based on risk factors) or universal screening is the most appropriate approach. Additionally, there is ongoing debate about what levels of glucose abnormalities during pregnancy respond best to treatment and which maternal and neonatal outcomes benefit most from treatment. Furthermore, the implications of possible screening options on health care costs are not well established. In response to this uncertainty there have been repeated calls for well-designed, randomised trials to determine the efficacy of screening, diagnosis, and management plans for GDM. We describe a randomised controlled trial to investigate screening uptake rates and the clinical and cost effectiveness of screening in primary versus secondary care settings.

METHODS/DESIGN

This will be an unblinded, two-group, parallel randomised controlled trial (RCT). The target population includes 784 women presenting for their first antenatal visit at 12 to 18 weeks gestation at two hospitals in the west of Ireland: Galway University Hospital and Mayo General Hospital. Participants will be offered universal screening for GDM at 24 to 28 weeks gestation in either primary care (n=392) or secondary care (n=392) locations. The primary outcome variable is the uptake rate of screening. Secondary outcomes include indicators of clinical effectiveness of screening at each screening site (primary and secondary) including gestational week at time of screening, time to access antenatal diabetes services for women diagnosed with GDM, and pregnancy and neonatal outcomes for women with GDM. In addition, parallel economic and qualitative evaluations will be conducted. The trial will cover the period from the woman's first hospital antenatal visit at 12 to 18 weeks gestation, until the completion of the pregnancy.

TRIAL REGISTRATION

Current Controlled Trials: ISRCTN02232125.

HbA1c for screening and diagnosis of diabetes mellitus

HbA1c has become the gold standard for monitoring glycemic control in patients with diabetes mellitus. The use of this test has been expanded to diagnose and screen for diabetes mellitus with the endorsement of influential diabetes societies and the World Health Organization. The literature on the use of HbA1c for the diagnosis and screening of diabetes mellitus was critically examined. There is substantial recent literature on this topic with strong advocates for the use of HbA1c to diagnose and screen for diabetes and equally strong detractors for its use. Advocates of the use of HbA1c cite challenges in respect of patient compliance and the analysis of glucose and inconsistency of diagnosis with glucose-based diabetes diagnosis with the elimination or reduction in these challenges in HbA1c-based diagnosis. Detractors of its use cite increased cost, concerns about the availability of HbA1c testing, and the influence of demographic and clinical factors on HbA1c results that make the use of a single-threshold values questionable for different ethnic and age groups. Despite the recommendation of many international diabetes societies that HbA1c be used for screening and diagnosis of diabetes mellitus, there is a wide divergence of opinion on this use.

NIH consensus development conference: diagnosing gestational diabetes mellitus

OBJECTIVE

To provide healthcare providers, patients, and the general public with a responsible assessment of currently available data on diagnosing gestational diabetes mellitus (GDM).

PARTICIPANTS

A non-U.S. Department of Health and Human Services, nonadvocate 15-member panel representing the fields of obstetrics and gynecology, maternal-fetal medicine, pediatrics, diabetic research, biostatistics, women's health issues, health services research, decision analysis, health management and policy, health economics, epidemiology, and community engagement. In addition, 16 experts from pertinent fields presented data to the panel and conference audience.

EVIDENCE

Presentations by experts and a systematic review of the literature prepared by the University of Alberta Evidence-based Practice Centre, through the Agency for Healthcare Research and Quality (AHRQ). Scientific evidence was given precedence over anecdotal experience.

CONFERENCE PROCESS

The panel drafted its statement based on scientific evidence presented in open forum and on published scientific literature. The draft statement was posted at http://prevention.nih.gov/ for public comment and the panel released a final statement approximately 10 weeks later. The final statement is an independent report of the panel and is not a policy statement of the NIH or the Federal Government.

CONCLUSIONS

At present, GDM is commonly diagnosed in the United States using a 1-hour screening test with a 50-gram glucose load followed by a 3-hour 100-gram glucose tolerance test (a two-step approach) for those found to be abnormal on the screen. This approach identifies approximately 5% to 6% of the population as having GDM. In contrast, newly proposed diagnostic strategies rely on the administration of a 2-hour glucose tolerance test (a one-step approach) with a fasting component and a 75-gram glucose load. These strategies differ on whether a 1-hour sample is included, whether two abnormal values are required, and the diagnostic cutoffs that are used. The International Association of Diabetes and Pregnancy Study Groups (IADPSG) has proposed diagnostic thresholds based on demonstrated associations between glycemic levels and an increased risk of obstetric and perinatal morbidities. The panel considered whether a one-step approach to the diagnosis of GDM should be adopted in place of the two-step approach. The one-step approach offers certain operational advantages. The current two-step approach is used only during pregnancy and is largely restricted to the United States. There would be value in a consistent, international diagnostic standard across one's lifespan. This unification would allow better standardization of best practices in patient care and comparability of research outcomes. The one-step approach also holds potential advantages for women and their health care providers, as it would allow a diagnosis to be achieved within the context of one visit as opposed to two. However, the one-step approach, as proposed by the IADPSG, is anticipated to increase the frequency of the diagnosis of GDM by twofold to threefold, to a prevalence of approximately 15% to 20%. There are several concerns regarding the diagnosis of GDM in these additional women. It is not well understood whether the additional women identified by this approach will benefit from treatment, and if so, to what extent. Moreover, the care of these women will generate additional direct and indirect health care costs. There is also evidence that the labeling of these women may have unintended consequences, such as an increase in cesarean delivery and more intensive newborn assessments. In addition, increased patient costs, life disruptions, and psychosocial burdens have been identified. Available studies do not provide clear evidence that a one-step approach is cost-effective in comparison with the current two-step approach. After much deliberation, the panel believes that there are clear benefits to international standardization with regard to the one-step approach. Nevertheless, at present, the panel believes that there is not sufficient evidence to adopt a one-step approach. The panel is particularly concerned about the adoption of new criteria that would increase the prevalence of GDM, and the corresponding costs and interventions, without clear demonstration of improvements in the most clinically important health and patient-centered outcomes. Thus, the panel recommends that the two-step approach be continued. However, given the potential benefits of a one-step approach, resolution of the uncertainties associated with its use would warrant revision of this conclusion.

Cost-effectiveness of screening strategies for identifying pediatric diabetes mellitus and dysglycemia

OBJECTIVE

To conduct a cost-effectiveness analysis of screening strategies for identifying children with type 2 diabetes mellitus and dysglycemia (prediabetes/diabetes).

DESIGN

Cost simulation study.

SETTING

A one-time US screening program.

STUDY PARTICIPANTS

A total of 2.5 million children aged 10 to 17 years.

INTERVENTION

Screening strategies for identifying diabetes and dysglycemia.

MAIN OUTCOME MEASURES

Effectiveness (proportion of cases identified), total costs (direct and indirect), and efficiency (cost per case identified) of each screening strategy based on test performance data from a pediatric cohort and cost data from Medicare and the US Bureau of Labor Statistics.

RESULTS

In the base-case model, 500 and 400 000 US adolescents had diabetes and dysglycemia, respectively. For diabetes, the cost per case was extremely high ($312 000-$831 000 per case identified) because of the low prevalence of disease. For dysglycemia, the cost per case was in a more reasonable range. For dysglycemia, preferred strategies were the 2-hour oral glucose tolerance test (100% effectiveness; $390 per case), 1-hour glucose challenge test (63% effectiveness; $571), random glucose test (55% effectiveness; $498), or a hemoglobin A1c threshold of 5.5% (45% effectiveness; $763). Hemoglobin A1c thresholds of 5.7% and 6.5% were the least effective and least efficient (ranges, 7%-32% and $938-$3370) of all strategies evaluated. Sensitivity analyses for diabetes revealed that disease prevalence was a major driver of cost-effectiveness. Sensitivity analyses for dysglycemia did not lead to appreciable changes in overall rankings among tests.

CONCLUSIONS

For diabetes, the cost per case is extremely high because of the low prevalence of the disease in the pediatric population. Screening for diabetes could become more cost-effective if dysglycemia is explicitly considered as a screening outcome.

Diagnostic performance of using one- or two-HbA1c cut-point strategies to detect undiagnosed type 2 diabetes and impaired glucose regulation within a multi-ethnic population

INTRODUCTION

We compared test performance and cost per case for strategies detecting diabetes on the oral glucose tolerance test (OGTT) using either (a) glycated haemoglobin (HbA1c) ≥ 6.5% (48 mmol/mol) or (b) two HbA1c thresholds where the first cut-point 'rules out' and the second 'rules in' diabetes. HbA1c values in between the thresholds require confirmatory glucose testing for diagnosis.

MATERIALS AND METHODS

We conducted an analysis of adults aged 40-75 years from the Leicester Ethnic Atherosclerosis and Diabetes Risk (LEADER) cohort (Leicester, UK), from 2002 to 2008, who underwent oral glucose tolerance testing (OGTT) and HbA1c testing.

RESULTS

From 8696 individuals (mean age 57.3 years, 73% white Europeans (WE) and 27% South Asians (SA)), HbA1c ≥ 6.5% produced sensitivity of 62.1% for detecting diabetes in WE and 78.9% in SA. Using two selected thresholds, HbA1c ≤ 5.8% (rule-in, 40 mmol/mol) and HbA1c ≥ 6.8% (rule-out, 51 mmol/mol) produced high sensitivity/specificity (> 91.0%) for detecting diabetes, however, 28.8% of the cohort with HbA1c 5.9%-6.7% required a subsequent glucose test. The two cut-point threshold produced a lower cost per case of diabetes detected in WE, compared to HbA1c ≥ 6.5% of £38.53 (1.89 to 86.81) per case, but was more expensive in SA by £84.50 (69.72 to 100.92) per case. Using a risk score to determine HbA1c testing, the same costs per case became £63.33 (23.33 to 113.26) in WE and £69.21 (55.60 to 82.41) in SA.

CONCLUSION

Using a two-threshold strategy may have some benefits over a single cut-point; however, 28.8% of individuals required two blood tests.

Gestational diabetes screening with the new IADPSG guidelines: a cost-effectiveness analysis

OBJECTIVE

This study investigates the cost effectiveness of gestational diabetes mellitus screening using the new International Association of Diabetes in Pregnancy Study Group (IADPSG) guidelines.

STUDY DESIGN

A decision analytic model was built comparing routine screening with the 2-hour (2h) oral glucose tolerance test (OGTT) vs the 1-hour glucose challenge test. All probabilities, costs, and benefits were derived from the literature. Base case, sensitivity analyses, and a Monte Carlo simulation were performed.

RESULTS

Screening with the 2h OGTT was more expensive, more effective, and cost effective at $61,503/quality-adjusted life year. In a 1-way sensitivity analysis, the more inclusive IADPSG diagnostic approach remained cost effective as long as an additional 2.0% or more of patients were diagnosed and treated for gestational diabetes mellitus.

CONCLUSION

Screening at 24-28 weeks' gestational age under the new IADPSG guidelines with the 2h OGTT is expensive but cost effective in improving maternal and neonatal outcomes. How the health care system will provide expanded care to this group of women will need to be examined.

The cost of diagnosing Type 2 diabetes mellitus by clinical opportunistic screening in general practice

AIMS

Type 2 diabetes is associated with serious complications and shortens life. Its prevalence is increasing rapidly worldwide and no cure is available. One logical response is to diagnose the condition as early as possible. Clinical opportunistic screening is one mechanism for making the diagnosis before symptoms are reported. This paper reports the cost of using this technique in UK general practice.

METHODS

In one UK general practice, the electronic medical records were searched to determine the number of blood glucose and oral glucose tolerance tests undertaken for non-pregnant adults without known diabetes over three consecutive years. The laboratory, staff and administrative costs associated with these screening tests were calculated. The records of all patients newly diagnosed with Type 2 diabetes during the same period were reviewed to identify diagnoses made by clinical opportunistic screening. Total costs were divided by the number of diagnoses to determine a cost per diagnosis detected by opportunistic screening.

RESULTS

During the study period, 5720 screening tests were conducted for 2763 patients. Over the 3 years, 86 patients were diagnosed with Type 2 diabetes, 54 (63%) via screening (yield 2.0%; number needed to screen 51.2). The screening costs totalled £ 20,372. The average cost per new screen-detected diagnosis was £ 377.

CONCLUSIONS

Almost two-thirds of new cases of Type 2 diabetes can be detected before symptoms are reported, at reasonable cost by opportunistic screening in general practice, without the use of extra resources. As an affordable alternative to population screening, clinical opportunistic screening merits further consideration.

Screening for gestational diabetes mellitus: are the criteria proposed by the international association of the Diabetes and Pregnancy Study Groups cost-effective?

OBJECTIVE

The International Association of the Diabetes and Pregnancy Study Groups (IADPSG) recently recommended new criteria for diagnosing gestational diabetes mellitus (GDM). This study was undertaken to determine whether adopting the IADPSG criteria would be cost-effective, compared with the current standard of care.

RESEARCH DESIGN AND METHODS

We developed a decision analysis model comparing the cost-utility of three strategies to identify GDM: 1) no screening, 2) current screening practice (1-h 50-g glucose challenge test between 24 and 28 weeks followed by 3-h 100-g glucose tolerance test when indicated), or 3) screening practice proposed by the IADPSG. Assumptions included that 1) women diagnosed with GDM received additional prenatal monitoring, mitigating the risks of preeclampsia, shoulder dystocia, and birth injury; and 2) GDM women had opportunity for intensive postdelivery counseling and behavior modification to reduce future diabetes risks. The primary outcome measure was the incremental cost-effectiveness ratio (ICER).

RESULTS

Our model demonstrates that the IADPSG recommendations are cost-effective only when postdelivery care reduces diabetes incidence. For every 100,000 women screened, 6,178 quality-adjusted life-years (QALYs) are gained, at a cost of $125,633,826. The ICER for the IADPSG strategy compared with the current standard was $20,336 per QALY gained. When postdelivery care was not accomplished, the IADPSG strategy was no longer cost-effective. These results were robust in sensitivity analyses.

CONCLUSIONS

The IADPSG recommendation for glucose screening in pregnancy is cost-effective. The model is most sensitive to the likelihood of preventing future diabetes in patients identified with GDM using postdelivery counseling and intervention.

An appropriate test for diagnosis of gestational diabetes mellitus

Early diagnosis of GDM is necessary to reduce maternal and fetal morbidity and mortality. As all approaches to diagnosis of GDM are costly and difficult, we meant to find an appropriate and simple way to perform this test. One-thousand six-hundred and fifty-three pregnant women were screened for GDM at 24-28 weeks of gestation. Initial screening was done by a glucose challenge test with 50 g glucose. If the 1-h blood glucose level exceeded 130 mg/dl, then a 3-h oral glucose tolerance test (OGTT) with 100 g glucose was performed, and diagnosis was established according to ADA criteria. For determining which plasma glucose level is the best test for diagnosis of GDM, we used receiver operative characteristic cures (ROC) by plotting sensitivity versus one minus specificity at different times of plasma glucose levels in OGTT. In 732 pregnant women with a positive GCT, a 2-h plasma glucose level above 150 mg/dl was the most powerful test for detecting GDM, which revealed a sensitivity and specificity of 0.84 (0.81-0.86) and 0.94 (CI: 0.92-0.96), respectively. The results of this study suggest that 2-h 100 g OGTT could be an appropriate approach to diagnose GDM, which is cost-effective and could reduce laboratory workload.

The cost of universal screening for gestational diabetes mellitus in Ireland

AIMS

To estimate the costs associated with universal screening for gestational diabetes mellitus in Ireland.

METHODS

Bottom-up, prevalence-based cost analysis. Healthcare activity identified using the Atlantic Diabetes in Pregnancy (ATLANTIC DIP) database was grouped into five categories: screening and testing, gestational diabetes treatment, prenatal care, delivery care and neonatal care. A vector of unit cost data (euros in 2008 prices) was applied to specified resource use and the total healthcare cost calculated. A series of one-way and probabilistic sensitivity analyses were undertaken to explore the uncertainty in the analysis.

RESULTS

When individual resource components were valued and aggregated, the total healthcare cost of gestational diabetes in Ireland was estimated at €12 433 320 (95% CI €9 298 228-16 778 193). The average cost per case detected was €1621 (95% CI €524-2603) and the average total cost per case detected and treated was €11 903 (95% CI €7645-16 121).

CONCLUSIONS

This research provides the first estimates of the healthcare costs associated with gestational diabetes mellitus in Ireland. Further research is required to determine the cost-effectiveness of gestational diabetes screening in the region with a view to improving resource allocation in this area in the future.

Cost of gestational diabetes-related antenatal visits in health care based on the Finnish Medical Birth Register

The aim was to evaluate frequency and costs of antenatal health care visits related to risk of gestational diabetes (GDM) using Birth Register. Costs among all GDM risk groups were 10-41% larger than non-risk groups. Primary health care is needed to reduce special health care costs related to GDM.

[Role of the fasting plasma glucose in diagnostic algorithm of gestational diabetes]

The International Association of Diabetes in pregnancy study groups (IADPSG) recommends all pregnant women to undergo oral glucose-tolerant test between 24 and 28 week of gestation. This might be expensive for the national health system and could overload the laboratory Furthermore, fasting plasma glucose (FPG) < 4.4 mmol/l is associated with very low risk of adverse pregnancy outcome.

AIM

Aim of the current study is to determine the prognostic value of FPG in the diagnosis of gestational diabetes (GDM) according to the criteria of IADPSG and American Diabetes Association (ADA).

MATERIALS AND METHODS

In the study were included 572 pregnant women between 24 and 28 week of gestation. Two thresholds of FPG were used to rule in or rule out the women into diagnosis of GDM.

RESULTS

According to IADPSG and ADA criteria, GDM was found in 181 (31.6%) and 77 (13.5%) women respectively (p<0.001). FPG thresholds of > or = 5.1 mmol/l ruled in GDM in 132 (23.1%) women with 100% specificity, while < 4.4 mmol/l ruled out GDM in 159 (27.8%) women with 95.6% sensitivity. If we decide to continue with OGTT in those women with FPG > or = 5.1 mmol/l to confirm the diagnosis, at least in 27.8% (159) OGTT could be avoided, because of the FPG < 4.4 mmol/l.

CONCLUSION

The IADPSG criteria increased GDM prevalence 2.4 fold. Taking into account the FPG is beneficial and cost-effective. It could simplify the IADPSG diagnostic algorithm.

Comparison of different stepwise screening strategies for type 2 diabetes: Finding from Danish general practice, Addition-DK

AIM

To examine attendance, number of people with T2DM and costs of three different stepwise screening strategies for T2DM in general practice (GP).

METHODS

Diabetes risk questionnaires were mailed to individuals aged 40-69 years from 45 general practices in 2001-2002 and individuals at high risk for T2DM, were asked to contact their GP to arrange a screening test. In 2005-2006, 26 general practices were randomised into two different opportunistic screening programmes (OP-direct and OP-subsequent) and risk questionnaires were distributed to individuals aged 40-69 years during GP consultations. In the OP-direct approach, high-risk individuals were offered to start the screening during the actual consultation while high-risk individuals in the OP-subsequent approach, were invited to a screening test at a later date. We report attendance, number of people with T2DM and costs of each screening approach.

RESULTS

The mail-distributed approach identified 0.8% of the target population with T2DM, the OP-direct approach and the OP-subsequent approach, 0.9% and 0.5% respectively. Cost per person with T2DM was in the mail-distributed approach: € 1058, OP-direct approach: € 707 and the OP-subsequent approach: € 727.

CONCLUSION

This study indicates that opportunistic screening identifies the same level of unknown diabetes as a mail-distributed approach but with lower costs.

13C- and 2H-labelled glucose compared for minimal model estimates of glucose metabolism in man

In the present study, we have investigated the use of 1-[(13)C]glucose and GC/combustion/isotope-ratio MS as an alternative to 6,6-[(2)H(2)]glucose and GC/MS in the determination of parameters of glucose metabolism using the IVGTT (intravenous glucose tolerance test) interpreted by labelled (hot) minimal models. The study has been done in four populations, normoglycaemics (subdivided into lean and obese individuals), subjects with impaired glucose tolerance and those with diabetes mellitus. Although the use of carbon label may in some circumstances be compromised by substrate recycling, our hypothesis was that this would not be an issue under the condition of suppression of hepatic glucose production during the short timescale of an IVGTT. In all four groups, we found that the methodology employing the carbon label gave equivalent results to those obtained using the conventional deuterated material, but the sensitivity of the measurement technique in the new approach was sufficient to allow an approx. 15-fold reduction in the quantity of isotope administered. In addition to the clear cost advantages, this represents a significant scientific advance in that true tracer status is more nearly attained in these measurements with near-physiological tracee loads.

Gestational diabetes: universal or selective screening?

OBJECTIVE

To evaluate the incidence of gestational diabetes in our population and verify costs of universal screening. To assess neonatal and obstetrical outcomes with respect to maternal epidemiological characteristics.

METHODS

Eight hundred and fifty-six pregnant women between 24th and 28th weeks of gestation were examined in this observational study. Universal screening with glucose challenge test was used to screen the group for gestational diabetes. History, obstetrical and neonatal outcomes were collected and then analyzed.

RESULTS

Gestational diabetes was diagnosed in 6.6% of cases. Patients with at least one risk factor had a cesarean section in 50% of cases and a spontaneous vaginal delivery in 23.59% of cases (p < 0.001). The absence of any risk factor was found in 73.7% of positive glucose tolerance test and in 62.5% of affected patients. The cost of universal screening in our study, was 57,60 Euros per case identified.

CONCLUSIONS

Given the high prevalence of diabetes, the high proportion of patients potentially not identified with a selective screening in this study and the relatively low cost, universal screening for gestational diabetes seems the best way to identify patients and prevent adverse obstetrical and neonatal outcomes.

Fasting plasma glucose versus glucose challenge test: screening for gestational diabetes and cost effectiveness

OBJECTIVE

To compare the performance in screening for gestational carbohydrate intolerance of the 1-h 50-g glucose challenge test (GCT), fasting plasma glucose (FPG) and fasting capillary glucose (FCG).

DESIGN AND METHODS

FPG and FCG were measured at the same time as the GCT in 188 women. Gestational carbohydrate intolerance was diagnosed according to the Canadian Diabetes Association criteria. We constructed receiver operator characteristic (ROC) curves and compared the sensitivity and specificity of the FPG, FCG and GCT.

RESULTS

Gestational diabetes was diagnosed in 11.2% women and gestational impaired glucose tolerance in 8.4%. The areas under the ROC curves for the FPG, the GCT and the FCG were not statistically different (P = 0.26). The GCT yielded a better specificity than the FPG and the FCG for a comparable level of sensitivity.

CONCLUSIONS

The GCT is better than the FPG in our population and is cost effective.

Is fasting blood glucose a reliable parameter for screening for diabetes in hypertension?

BACKGROUND

The aim of this study was to evaluate the sensitivity and specificity of a combination of fasting plasma glucose (FPG) and glycosylated hemoglobin (HbA(1c)) for screening for diabetes in hypertensive patients. The oral glucose tolerance test (OGTT) served as a gold standard for the detection of diabetes.

METHODS

The cross-sectional study was performed in the Hypertension Unit of the Department of Emergency Medicine in the General Hospital of Vienna between January 1999 and July 2001. The FPG, HbA(1c), and OGTT were performed in 152 hypertensive patients (77 male and 75 female) to identify those individuals with diabetes.

RESULTS

A total of 33 patients were identified as diabetic based on the results of the OGTT. Diabetes was detected in 25 (16%) of 152 patients using an FPG > or =7.0 mmol/L. In addition, HbA(1c) was measured in the remaining 127 (84%) patients with an FPG <7.0 mmol/L. In these patients HbA(1c) > or =6.1% showed a sensitivity of 100% and a specificity of 75%. Cost analysis of both approaches (FPG + HbA(1c) versus OGTT in all patients) demonstrated a cost sparing effect of 31.03 $/patient (31.66$/patient) in favor of the combined use of FPG and HbA(1c).

CONCLUSION

The combination of FPG and HbA(1c) is a reasonable alternative to the generally recommended OGTT for the screening of diabetes, as diabetes was correctly diagnosed in all patients by this stepwise procedure.

Tests of glycemia for the diagnosis of type 2 diabetes mellitus

This paper discusses tests of glycemia for the diagnosis of type 2 diabetes mellitus, with particular reference to the 1997 diagnostic criteria of the American Diabetes Association. The potential benefits of the lower diagnostic threshold for fasting plasma glucose are not well defined. However, the change in the diagnostic cut-off for diabetes mellitus affects as many as 1.9 million persons in the United States; therefore, the medical and social costs of the lower threshold may be considerable. Type 2 diabetes mellitus is defined by a threshold imposed on the continuous distribution of glycemic levels, typically with respect to risk for microvascular complications. However, the burden of type 2 diabetes relates more to macrovascular than microvascular complications. Because no clear threshold exists for macrovascular complications, a formal balancing of direct and indirect costs with both microvascular and macrovascular complications may be appropriate to establish glycemic thresholds. Because fasting plasma glucose, hemoglobin A1c, and the oral glucose tolerance test all predict diabetic complications yet test reliability is better for fasting plasma glucose and hemoglobin A1c than for the oral glucose tolerance test, we suggest an alternative diagnostic approach: If random plasma glucose is elevated (> or =11.1 mmol/L [200 mg/dL]) and the hemoglobin A1c level is more than 2 SDs above the laboratory mean, then diabetes mellitus should be diagnosed, and management should be based on the hemoglobin A1c level. If the result of only one of these tests is positive, then fasting plasma glucose should be tested to evaluate the patient for impaired fasting glucose and diabetes mellitus. The glycemic threshold for type 2 diabetes should be established by cost-effectiveness analysis. The clinical diagnosis of diabetes mellitus could be streamlined by incorporation of hemoglobin A1c into established criteria.

Cost-effectiveness analysis of gestational diabetes mellitus screening in France

OBJECTIVE

To compare three strategies for gestational diabetes screening (i) screening of high-risk pregnant women with the 50 g oral glucose tolerance test (OGTT); (ii) screening of all pregnant women with the 50 g OGTT; (iii) screening of all pregnant women according to the 75 g OGTT.

STUDY DESIGN

Cost-effectiveness analysis. The outcome measures, i.e. macrosomia, prematurity, perinatal mortality, hypertensive disorders rates were estimated from published studies and the costs from a prospective study involving 120 pregnant women.

RESULTS

Compared to the first strategy, the cost to obtain one unit of additional effectiveness with the second screening strategy, was up to 1.1 times more expensive, and with the third strategy was up to 3.7 times more expensive.

CONCLUSION

The costs per case prevented reflect a favourable cost-effectiveness ratio (CER) for screening of high-risk pregnant women by 50 g oral glucose test.

Measurement of insulin sensitivity indices using 13C-glucose and gas chromatography/combustion/isotope ratio mass spectrometry

Important aspects of glucose metabolism can be quantified by using the minimal model of glucose kinetics to interpret the results of intravenous glucose tolerance tests. The power of this methodology can be greatly increased by the addition of stable isotopically labelled tracer to the glucose bolus dose. This allows the separation of glucose disposal from endogenous glucose production and also increases the precision of the estimates of the physiological parameters measured. Until now the tracer of choice has been deuteriated glucose and the analytical technique has been gas chromatography/mass spectrometry (GC/MS). The consequence of this choice is that nearly 2 g of labelled material are needed and this makes the test expensive. We have investigated the use of (13)C-labelled glucose as the tracer in combination with gas chromatography/combustion/isotope ratio mass spectrometry (GC/C/IRMS) as the analytical technique. This methodology offers superior analytical precision when compared with the conventional method and so the amount of tracer used, and hence the cost, can be reduced considerably. Healthy non-obese male volunteers were recruited for a standard intravenous glucose tolerance test (IVGTT) protocol but 6,6-(2)H-glucose and 1-(13)C-glucose were administered simultaneously. Tracer/tracee ratios were derived from isotope ratio measurements of plasma glucose using both GC/MS and GC/C/IRMS. The results of these determinations indicated that the two tracers behaved identically under the test protocol. The combination of these results with plasma glucose and insulin concentration data allowed determination of the minimal model parameters S*g and S*i. The parameter relating to insulin-assisted glucose disposal, S*i, was found to be the same in the two techniques, but this was not the case for the non-insulin-dependent parameter S*g.

Risk factor screening for abnormal glucose tolerance in pregnancy

OBJECTIVES

To assess the prevalence and association of frequently used screening risk factors for gestational diabetes mellitus (GDM) and to compare the validity and cost of universal screening with risk factor screening.

METHOD

A cross-sectional survey of 768 pregnant women at > or = 24 weeks' gestation who were attending the antenatal clinic at the Hospital Universiti Kebangsaan Malaysia (HUKM) was made. Risk factors were determined using a questionnaire. An abnormal oral glucose tolerance test was defined as a 2-h post-prandial blood sugar level of > or = 7.8 mmol/l.

RESULTS

A total of 191 pregnant mothers (24.9%) had GDM. The most commonly identified screening factors were positive family history of diabetes mellitus (31.4%), history of spontaneous abortion (17.8%), vaginal discharge and pruritus vulvae in current pregnancy (16.0%), and maternal age greater than 35 years (14.7%). Five hundred and thirteen mothers (66.8%) had at least one risk factor. All screening risk factors, except past history of diabetes mellitus in previous pregnancy and maternal age, were not significantly associated with abnormal glucose tolerance (GT). Risk factor screening gave a sensitivity of 72.2% and a specificity of 35.0%. Universal screening would cost RM 12.06 while traditional risk factor screening would cost RM 11.15 per identified case and will have missed 53 of the 191 cases.

CONCLUSIONS

Risk factor screening scored poorly in predicting GDM. Cost analysis of universal compared with traditional risk factor screening showed a negligible difference. Thus universal screening appears to be the most reliable method of diagnosing GDM.

A comparison of costs associated with screening for gestational diabetes with two-tiered and one-tiered testing protocols

OBJECTIVE

The Fourth International Workshop on Gestational Diabetes recently suggested that two techniques, a 2-tiered protocol and a 1-tiered protocol, to screen for gestational diabetes mellitus are acceptable alternatives. This study was undertaken to compare the direct costs and patient time expenditures associated with implementing both techniques.

STUDY DESIGN

A MEDLINE search was undertaken to determine the prevalence of positive and negative screening results. Direct costs of testing were estimated by determining the range of supply costs from manufacturers' catalogs and the labor costs by estimating the time required to perform each procedure and multiplying by the appropriate range of wages; these costs were then multiplied by the appropriate range of the number of procedures required to implement both protocols, and the totals were summed. Patient time expended was estimated by assigning test times of 1, 2, and 3 hours for the 50-g screening glucose challenge test, the 75-g oral glucose tolerance test, and the 100-g oral glucose tolerance test, respectively. If additional visits were required, 2 travel-time units were assigned each time a patient underwent a procedure. These units were multiplied by the range of patients undergoing various tests to implement the alternative protocols.

RESULTS

We identified low and high direct costs, test times, and travel units per patient screened by the 1- and 2-tiered testing protocols. Low and high direct costs were $3.46 and $7.88, respectively, for the 2-tiered protocol and $5.64 and $10.88, respectively, for the 1-tiered protocol (relative ratios, 1.63 for low direct costs in each protocol and 1.38 for high direct costs in each protocol). Low and high test times were 1.4 and 1.5 hours, respectively, for the 2-tiered protocol and 2.0 and 2.0 hours, respectively, for the 1-tiered protocol (relative ratios, 1.47 for low test times in each protocol and 1.32 for high test times in each protocol). Low and high travel units for the 2-tiered protocol were 0.2 and 0.3, respectively, when the glucose challenge test was given at the prenatal visit, and 2.2 and 2.3, respectively, when the test was not given at that time. Low and high travel units for the 1-tiered protocol were 8.3 and 5.8, respectively, when the glucose challenge test was given at the prenatal visit, and 0.89 and 0.85, respectively, when the test was not given at that time.

CONCLUSIONS

The 2-tiered protocol appears to be associated with lower direct implementation costs and less patient time expenditure than the 1-tiered scheme. The 1-tiered protocol is associated with slightly less travel time, but this is unlikely to offset the test time advantage of the 2-tiered protocol. Until further data regarding the relative clinical utility of the 2 protocols become available, these factors may be important for clinicians in deciding which screening format to follow.

Selective screening for gestational diabetes mellitus in adolescent pregnancies

OBJECTIVE

It is unclear whether it is cost-effective to universally screen adolescent gravidas for gestational diabetes mellitus (GDM). Our objective was to identify the prevalence of gestational diabetes in our adolescent population and to review risk factors that would most easily identify a subset of adolescent patients at greatest risk for the development of gestational diabetes.

METHODS

Six hundred thirty-two adolescents were identified from 11,486 deliveries in our institution through International Classification of Diseases (9th edition) codes. Eleven of those adolescents had GDM. Their charts and those of a representative group of nondiabetic adolescent gravidas were analyzed for GDM risk factors, including race/ethnicity, body mass index (BMI), family history of diabetes, other medical disorders, and previous history of GDM, macrosomia, stillbirths, or anomalous fetus. Statistical analyses used chi2 and Student t tests as appropriate.

RESULTS

The prevalence of GDM among adolescent gravidas was 1.7%. No difference was identified between the adolescent pregnancies with GDM and the comparison group for race/ethnicity, family history, or presence of medical disorders. Risk factors requiring a previous obstetric history could not be evaluated adequately because of the high prevalence of nulliparas. There was a higher prevalence of BMI over 27 in adolescents with GDM (P < .001).

CONCLUSION

Body mass index is an important risk factor for the development of gestational diabetes in adolescent gravidas. We recommend that selective screening for GDM of adolescent gravidas be performed on the basis of BMI.

The cost-effectiveness of screening for type 2 diabetes. CDC Diabetes Cost-Effectiveness Study Group, Centers for Disease Control and Prevention

CONTEXT

Type 2 diabetes mellitus is a common and serious disease in the United States, but one third of those affected are unaware they have it.

OBJECTIVE

To estimate the cost-effectiveness of early detection and treatment of type 2 diabetes.

DESIGN

A Monte Carlo computer simulation model was developed to estimate the lifetime costs and benefits of 1-time opportunistic screening (ie, performed during routine contact with the medical care system) for type 2 diabetes and to compare them with current clinical practice. Cost-effectiveness was estimated for all persons aged 25 years or older, for age-specific subgroups, and for African Americans. Data were obtained from clinical trials, epidemiologic studies, and population surveys, and a single-payer perspective was assumed. Costs and benefits are discounted at 3% and costs are expressed in 1995 US dollars.

SETTING

Single-payer health care system.

PARTICIPANTS

Hypothetical cohort of 10000 persons with newly diagnosed diabetes from the general US population.

MAIN OUTCOME MEASURES

Cost per additional life-year gained and cost per quality-adjusted life-year (QALY) gained.

RESULTS

The incremental cost of opportunistic screening among all persons aged 25 years or older is estimated at $236449 per life-year gained and $56649 per QALY gained. Screening is more cost-effective among younger people and among African Americans. The benefits of early detection and treatment accrue more from postponement of complications and the resulting improvement in quality of life than from additional life-years.

CONCLUSIONS

Early diagnosis and treatment through opportunistic screening of type 2 diabetes may reduce the lifetime incidence of major microvascular complications and result in gains in both life-years and QALYs. Incremental increases in costs attributable to screening and earlier treatment are incurred but may well be in the range of acceptable cost-effectiveness for US health care systems, especially for younger adults and for some subpopulations (eg, minorities) who are at relatively high risk of developing the major complications of type 2 diabetes. Although current recommendations are that screening begin at age 45 years, these results suggest that screening is more cost-effective at younger ages. The selection of appropriate target populations for screening should consider factors in addition to the prevalence of diabetes.

Gestational diabetes mellitus; resource utilization and costs of diagnosis and treatment

The recommendation to test every woman for gestational diabetes mellitus (GDM) has a defined cost. The management of women diagnosed with GDM will use additional health resources. This examines the cost and resource utilization of a consecutive group of women diagnosed over a 1-year period. The cost of testing a woman for GDM is around $10.00 with slight variations depending on the testing procedure. The annual cost of testing in NSW would be less than 1 million dollars. Women diagnosed with GDM used the resources of a diabetes education centre for an average of 2.8 hours and attended for 3.4 (2.3) medical visits. Insulin was required by 18.7% of the women for 9.7 (4.7) weeks using 47.7 (21.2) units each day. Testing women for GDM is a low-cost item. Managing a woman diagnosed with GDM may cost several hundred dollars. Cost reductions could be made by reducing the amount of insulin used and by avoiding hospitalization.

A comparison of the 3 H glucose tolerance test and the 2 H value in identifying risk for excessive fetal growth

The objective of this study was to determine if the 2 h value of the glucose tolerance test (GTT) is as reliable as the complete GTT in identifying risk for excessive fetal growth. Five hundred eighty-eight patients underwent a 3 h oral GTT at 26-28 weeks' gestation. The 2 h value of the test was compared to the results of the GTT. The incidence of large for gestational age (LGA) infants was compared for patients who had an abnormal GTT or an abnormal 2 h value only. A normal 2 h value was associated with a normal GTT in 98.5% of cases, while an abnormal 2 h value was associated with an abnormal GTT in 70% of cases. An abnormal GTT was associated with a 22% incidence of LGA, while a 2 h value > or = 165 mgm/dl was associated with a 20% incidence of LGA. This difference was not statistically significant. A single 2 h value GTT is more cost-effective and as predictive as a complete 3 h GTT in identifying risk for excessive fetal growth.

Exploration of simple insulin sensitivity measures derived from frequently sampled intravenous glucose tolerance (FSIGT) tests. The Insulin Resistance Atherosclerosis Study

Both abnormal insulin levels and low insulin sensitivity have been implicated as risk factors for Type II diabetes mellitus and cardiovascular disease. While insulin level is relatively simple to assess, direct measurement of insulin sensitivity is much more invasive, costly, and time-consuming. The authors considered eight previously described measures or indices of indices of insulin sensitivity derived from the frequently sampled intravenous glucose tolerance test (FSIGT). Each one was evaluated by strength and consistency of association with insulin sensitivity computed from glucose clamp (SI(clamp)), across three glucose tolerance groups, including participants with normal glucose tolerance (n = 11), impaired glucose tolerance (n = 20), and non-insulin-dependent diabetes mellitus (n = 24). Minimal model analysis (MINMOD SI(22)), based on the 22-sample FSIGT, performed best based on statistical criteria of strong and consistent association with SI(clamp). An insulin sensitivity measure similar to that of Galvin et al. (Diabetic Medicine 1990;9:921-8), defined as glucose disappearance (10-50 minutes) divided by insulin area under the curve above baseline from 0-50 minutes, performed best based on statistical criteria and time-savings. Galvin insulin sensitivity is simple to calculate, requires only a 50-minute FSIGT, and is significantly (p < 0.001) and not inconsistently (p = 0.12 for inconsistent association) associated with SI(clamp) over a wide range of glucose tolerance.

Gestational diabetes in Papua New Guinea

Pacific populations have some of the highest prevalences for diabetes in the world. Whilst universal screening for diabetes in pregnancy does yield the best pick-up rate it is not economically feasible in developing countries. Traditional risk factors have increasingly been shown to miss most gestational diabetes, particularly in populations for whom family history is unknown and obstetrical history not recorded. This study shows genetic origin to be a potent marker for gestational diabetes in a Pacific Island population. It is recommended that in Port Moresby 'at-risk ethnicity' (urban Motuan or Marshall Lagoon origin) be added to the list of indications for antenatal glucose tolerance testing in Papua New Guinean women.

Cost-effective evaluation of impotence

Two hundred consecutive men presenting with a chief complaint of impotence have been evaluated with a protocol involving one or two outpatient visits. The initial evaluation for all patients consisted of a history taken in a conventional manner and supplemented by a patient-completed sexual function questionnaire, physical examination, serum testosterone and prolactin, and two-night nocturnal penile tumescence studies. Following the initial evaluation the patients were placed in one of three categories: (1) organic impotence, (2) functional impotence, (3) ambiguous impotence (mixed functional and organic impotence or organic impotence of undetermined etiology). Patients in the latter group underwent additional testing including penile vascular studies, two-hour oral glucose tolerance test, and psychiatric consultation. With this protocol, patients can be efficiently and effectively evaluated as outpatients with costs ranging from +250 to +450.