Is the Current Cut Point for Glycated Haemoglobin (HbA1c) Correct for Diagnosing Diabetes Mellitus in Premenopausal Women? Evidence to Inform Discussion

INTRODUCTION

Women are on average diagnosed with diabetes mellitus at later age than men but have higher mortality. As the diagnosis of diabetes mellitus is primarily based on HbA1c, the use of a non-specific reference range and cut point for diabetes mellitus that does not account for gender differences in diabetes could potentially lead to underdiagnosis of diabetes mellitus in women and missed opportunities for intervention. We investigated whether a contributing factor to the later diagnosis in women may be a difference in distribution of HbA1c in premenopausal women versus men of the same age by comparing HbA1c values in men and women across multiple sites in the UK.

METHODS

We analysed the HbA1c levels of 146,907 individuals who underwent single testing only and had HbA1c ≤ 50 mmol/mol between 2012 and 2019 in one laboratory (cohort 1). This was replicated in six laboratories with 938,678 individuals tested between 2019 and 2021 (cohort 2).

RESULTS

In cohort 1, women < 50 years old had an HbA1c distribution markedly lower than that in men by a mean of 1.6 mmol/mol (p < 0.0001), while the difference in the distribution of HbA1c for individuals aged ≥ 50 years was less pronounced (mean difference 0.9 mmol/mol, p < 0.0001). For individuals under the age of 50, HbA1c in women lagged by up to 10 years compared to men. Similar findings were found in cohort 2. We estimated an additional 17% (n = 34,953) of undiagnosed women aged < 50 years in England and Wales could be reclassified to have diabetes mellitus, which may contribute to up to 64% of the difference in mortality rates between men/women with diabetes mellitus aged 16-50 years.

CONCLUSION

The HbA1c cut point for diagnosis of diabetes mellitus may need to be re-evaluated in women under the age of 50 years. Early identification of diabetes mellitus in women has the potential to improve women's health outcomes in the longer term.

The Utility of Salivary Cortisone in the Overnight Dexamethasone Suppression Test in Adrenal Incidentalomas

CONTEXT

Guidelines recommend the assessment of cortisol secretion in patients with adrenal incidentalomas (AI) using the overnight dexamethasone suppression test (ONDST). This requires attendance at a health care facility and venepuncture. Alternatively, the ONDST can be done by measuring salivary cortisol and cortisone, which can be collected at home.

OBJECTIVE

We aimed to assess the utility of these measurements in patients with AI.

METHODS

A retrospective analysis of data from 173 patients with AI who underwent an ONDST and salivary cortisol/cortisone diurnal studies. Serum and salivary cortisol and salivary cortisone were collected at 09:00, late night, and at 09:00 the following morning after dexamethasone. Dexamethasone levels were measured in the postdexamethasone samples. Serum and salivary samples were analyzed with liquid chromatography-tandem mass spectrometry.

RESULTS

We identified a strong correlation between salivary cortisone and serum cortisol after 1 mg of dexamethasone (r = 0.95). Stepwise multivariate regression showed that postdexamethasone salivary cortisone, baseline serum cortisol, salivary cortisone suppression (predexamethasone/postdexamethasone ratio), and sex were the only significant or near-significant independent variables. Performance of predictive indices using these 4 parameters (sensitivity = 88.5%, specificity = 91.2%; kappa 0.80) and postdexamethasone salivary cortisone alone (sensitivity = 85.3%, specificity = 91.7%; kappa 0.77) were comparable when used to predict an ONDST serum cortisol of ≤50 nmol/L. No correlation was observed with any of the other measured parameters.

CONCLUSION

In AI patients, after dexamethasone, salivary cortisone correlates very strongly with serum cortisol in the ONDST and could therefore be used as an alternative sampling method which does not require venepuncture or attendance at hospital.

Variability in Test Interval Is Linked to Glycated Haemoglobin (HbA1c) Trajectory over Time

AIMS

We previously showed that the glycated haemoglobin (HbA1c) testing frequency links to diabetes control. Here, we examine the effect of variability in test interval, adjusted for the frequency, on change in HbA1c (ΔHbA1c). Materials & Methods. HbA1c results were collected on 83,872 people with HbA1c results at baseline and 5 years (±3 months) later and ≥6 tests during this period. We calculated the standard deviation (SD) of test interval for each individual and examined the link between deciles of SD of the test interval and ΔHbA1c level, stratified by baseline HbA1c.

RESULTS

In general, less variability in testing frequency (more consistent monitoring) was associated with better diabetes control. This was most evident with moderately raised baseline HbA1c levels (7.0-9.0% (54-75 mmol/mol)). For example, in those with a starting HbA1c of 7.0-7.5% (54-58 mmol/mol), the lowest SD decile was associated with little change in HbA1c over 5 years, while for those with the highest decile, HbA1c rose by 0.4-0.6% (4-6 mmol/mol; p < 0.0001). Multivariate analysis showed that the association was independent of the age/sex/hospital site. Subanalysis suggested that the effect was most pronounced in those aged <65 years with baseline HbA1c of 7.0-7.5% (54-58 mmol/mol). We observed a 6.7-fold variation in the proportion of people in the top-three SD deciles across general practices.

CONCLUSIONS

These findings indicate that the consistency of testing interval, not the just number of tests/year, is important in maintaining diabetes control, especially in those with moderately raised HbA1c levels. Systems to improve regularity of HbA1c testing are therefore needed, especially given the impact of COVID-19 on diabetes monitoring.

Adrenal Incidentaloma: Prevalence and Referral Patterns From Routine Practice in a Large UK University Teaching Hospital

Context

Adrenal incidentalomas (AIs) are increasingly being identified during unrelated imaging. Unlike AI clinical management, data on referral patterns in routine practice are lacking.

Objective

This work aimed to identify factors associated with AI referral.

Methods

We linked data from imaging reports and outpatient bookings from a large UK teaching hospital. We examined (i) AI prevalence and (ii) pattern of referral to endocrinology, stratified by age, imaging modality, scan anatomical site, requesting clinical specialty, and temporal trends. Using key radiology phrases to identify scans reporting potential AI, we identified 4097 individuals from 479 945 scan reports (2015-2019). Main outcome measures included prevalence of AI and referral rates.

Results

Overall, AI lesions were identified in 1.2% of scans. They were more prevalent in abdomen computed tomography and magnetic resonance imaging scans (3.0% and 0.6%, respectively). Scans performed increased 7.7% year-on-year from 2015 to 2019, with a more pronounced increase in the number with AI lesions (14.7% per year).Only 394 of 4097 patients (9.6%) had a documented endocrinology referral code within 90 days, with medical (11.8%) more likely to refer than surgical (7.2%) specialties (P < .001). Despite prevalence increasing with age, older patients were less likely to be referred (P < .001).

Conclusion

While overall AI prevalence appeared low, scan numbers are large and rising; the number with identified AI are increasing still further. The poor AI referral rates, even in centers such as ours where dedicated AI multidisciplinary team meetings and digital management systems are used, highlights the need for new streamlined, clinically effective systems and processes to appropriately manage the AI workload.

Adrenal lesions found incidentally: how to improve clinical and cost-effectiveness

Introduction

Adrenal incidentalomas are lesions that are incidentally identified while scanning for other conditions. While most are benign and hormonally non-functional, around 20% are malignant and/or hormonally active, requiring prompt intervention. Malignant lesions can be aggressive and life-threatening, while hormonally active tumours cause various endocrine disorders, with significant morbidity and mortality. Despite this, management of patients with adrenal incidentalomas is variable, with no robust evidence base. This project aimed to establish more effective and timely management of these patients.

Methods

We developed a web-based, electronic Adrenal Incidentaloma Management System (eAIMS), which incorporated the evidence-based and National Health Service–aligned 2016 European guidelines. The system captures key clinical, biochemical and radiological information necessary for adrenal incidentaloma patient management and generates a pre-populated outcome letter, saving clinical and administrative time while ensuring timely management plans with enhanced safety. Furthermore, we developed a prioritisation strategy, with members of the multidisciplinary team, which prioritised high-risk individuals for detailed discussion and management. Patient focus groups informed process-mapping and multidisciplinary team process re-design and patient information leaflet development. The project was partnered by University Hospital of South Manchester to maximise generalisability.

Results

Implementation of eAIMS, along with improvements in the prioritisation strategy, resulted in a 49% reduction in staff hands-on time, as well as a 78% reduction in the time from adrenal incidentaloma identification to multidisciplinary team decision. A health economic analysis identified a 28% reduction in costs.

Conclusions

The system’s in-built data validation and the automatic generation of the multidisciplinary team outcome letter improved patient safety through a reduction in transcription errors. We are currently developing the next stage of the programme to proactively identify all new adrenal incidentaloma cases.

Efficacy and Cardiovascular Safety of SGLT2 Inhibitors

Patients with diabetes continued to exhibit a high risk for cardiovascular and renal events despite achieving satisfactory glycemic, blood pressure and lipid targets. Studies evaluating new diabetes medications focused on cardiovascular events, largely overlooking heart failure (HF). The latter has recently been recognised as a major cause of morbidity and mortality in patients with diabetes mellitus. There had been an unmet need for drugs with cardiovascular (including HF) and renal protection, with an expectation that an ideal diabetic drug should improve these endpoints. Moreover, an ideal drug should have weight reducing benefits. Recently published outcome trials have shown that sodium-glucose cotransporter 2 (SGLT2) inhibitors and glucagon-like peptide 1 receptor agonists (GLP-1RAs) can reduce cardiovascular and renal events, together with statistically significant weight reduction. As a result, many recently published international guidelines have recommended SGLT2 inhibitors and GLP-1RAs in patients with diabetes and pre-existing cardiovascular disease (CVD). In this review, we will critically analyse the efficacy and cardiovascular (CV) safety of SGLT2 inhibitors, based on the available literature to help position them in the clinical decision process.

SAT-174 Adrenal Incidentalomas: Prevalence and Referral Patterns in a UK University Hospital Using Real-Life Data

The estimated prevalence of adrenal incidentaloma at abdominal CT scan is 0.5-2% (1). However, from clinical practice, we noticed that incidentalomas are referred from other imaging modalities (eg MRI) and of other sites (eg thorax, spine). We therefore explored the relationship between prevalence rates and (i) imaging modality and (ii) its change over time, in a real world clinical setting from a large UK teaching hospital/trauma centre. We also examined the referral pattern of potential lesions to endocrinology. We extracted data from all radiology reports for all CT and MRI scans from Jan 2018-Oct 2019. We utilised a key phrase search strategy (eg adrenal adenoma/lesion/mass/nodule/incidentaloma, incidental adrenal, indeterminate adrenal). Where possible we excluded false hits (eg no adrenal lesion). These were linked to the referral patterns as identified by a referral logged or an attendance (new or follow-up) to endocrine clinic 3 months post index scan. Preliminary data showed that, from a total of 127878 scans performed, 2604 potential lesions were reported (prevalence 2.0%), comprising 2496/88838 (2.8%) CT scans and 108/39040 (0.3%) MRI scans. The number of scans/month increased in 2019 vs 2018 (6.9% for CT and 12.6% for MRI). Only 9.0% and 15.7% of reported potential lesions detected by CT and MRI, respectively, were referred for endocrine review. Hence, MRI patients were more likely to be referred than those with CT scans (p=0.018). Referral rates were lower in 2019 than 2018 (8.6% vs 14.4%; p less than 0.001). This approach has its limitations but allows efficiently review of large cohorts. Adrenal incidentalomas pose a rising challenge in view of increasing reliance on scanning. Despite a dedicated adrenal multidisciplinary team with a national track record in improving management of incidentalomas (2), the referral rate of potential lesions is worryingly low and not improving, with >90% of cases overlooked. This work is part of on-going innovation to enhance the pick-up rate for these cases whilst addressing the increased endocrine workload in a cost-effective manner. 1. Barzon L, Sonino N, Fallo F, Palu G, Boscaro M. Prevalence and natural history of adrenal incidentalomas. Eur J Endocrinol. 2003;149:273-285. 2. Hanna FWF, Issa BG, Lea SC, George C, Golash A, Firn M, Ogunmekan S, Maddock E, Sim J, Xydopoulos G, Fordham R, Fryer AA. Adrenal lesions found incidentally: how to improve clinical and cost-effectiveness. BMJ Open Quality. 2019;In press.

SAT-168 Adrenal Incidentalomas: Impact of Patient Age on Referral Rates for Endocrine Evaluation

It is estimated that the prevalence of adrenal incidentaloma increases with age: ~3% of those aged 50 years, rising to 10% in those >70 years (1). Given the aging population together with increased utilisation of cross-sectional imaging in the UK (eg CT urogram, MR angiogram), we explored the proportion of patients with adrenal incidentaloma by age based on current imaging trends. Furthermore, there is no information currently available on the relationship between age and pattern of endocrine referrals. We extracted data for all CT and MRI scans from Jan 2018-Oct 2019 and used key phrases in radiology reports (eg adrenal adenoma/lesion/mass/nodule/incidentaloma, incidental adrenal, indeterminate adrenal) to identify potential lesions. We also extracted data on patient age and referral patterns as identified by a logged referral or an attendance (new or follow-up) to endocrine clinic 3 months post index scan, stratified by 10 year age groups. Where possible, we excluded false hits (eg no adrenal lesion). Preliminary data showed that, of the 2604 potential lesions identified by CT and MRI scans, 78.7% were on patients aged over 60 years. The numbers of identified lesions gradually increased with age to a peak in the 71-80 year age group after which these declined. Whilst patients younger that 60 years had fewer potential lesions identified, they were more likely to be referred to endocrine services (73 out of 55 patients; 13.2%) than those in the older age group (168 out of 2049; 8.2%; p<0.001). Indeed there was a statistically significant trend towards decreasing referral with age group (Chi-squared test for trend; p<0.001). In conclusion, patients over 60 years have a higher number of potential adrenal incidentalomas. However, this group is less likely to be referred for endocrine evaluation. This is particularly concerning given the large number of scans requested and the higher prevalence of incidentalomas in this age group. This study represents preparatory work on innovations to enhance case detection, particularly in the older age groups (2). 1. Fassnacht M, Arlt W, Bancos I, et al. Management of adrenal incidentalomas: European Society of Endocrinology Clinical Practice Guideline. Eur J Endocrinol. 2016;175:G1-G34 2. Hanna FWF, Issa BG, Lea SC, George C, Golash A, Firn M, Ogunmekan S, Maddock E, Sim J, Xydopoulos G, Fordham R, Fryer AA. Adrenal lesions found incidentally: how to improve clinical and cost-effectiveness. BMJ Open Quality. 2019;In press.

SAT-161 Adrenal Incidentalomas: Pattern of Referral According to Clinical Specialty

Whilst the estimated prevalence of adrenal incidentaloma is 0.5-2% following abdominal CT scan (1), little is known about subsequent endocrine referral patterns according to clinical specialty. We therefore examined the range of specialties that were responsible for requesting CT and MRI scans that led to reporting potential adrenal lesions. We also explored the referral pattern to endocrinology following identification. We extracted data from all radiology reports for all CT and MRI scans from Jan 2018-Oct 2019. We utilised a key phrase search strategy (eg adrenal adenoma/lesion/mass/nodule/incidentaloma, incidental adrenal, indeterminate adrenal). Where possible we excluded false hits (eg no adrenal lesion). These were lined to the referral patterns as identified by a referral logged or an attendance (new or follow-up) to endocrine clinic 3 months post index scan. These data were stratified by requesting specialty. Preliminary data showed that, out of 127878 scans, 2021 patients were identified to have a potential adrenal incidentaloma. These requests came from a total of 45 different clinical specialities (medical and surgical). The top 12 specialties accounted from 82.8% of these referrals. Medical specialties (renal, gastroenterology, respiratory, general medicine, acute medicine and geriatric medicine) accounted for 50.2%. The remaining 32.6% were via surgical specialities. The overall referral pattern in these cases was 8.5% with no difference between medical (8.6%) and surgical (8.4%) specialties. In conclusion, adrenal incidentalomas are potentially identifiable across a wide range of specialties. Currently, despite a dedicated adrenal multidisciplinary team and nationally-acknowledged quality improvement programme for the management of adrenal incidentalomas (2), the majority of cases are overlooked and not referred for endocrine review as suggested in current guidelines. We expect the findings in our centre to be reproducible elsewhere. We are considering innovative approaches to improve the process and cope with the additional workload cost-effectively. 1. Barzon L, Sonino N, Fallo F, Palu G, Boscaro M. Prevalence and natural history of adrenal incidentalomas. Eur J Endocrinol. 2003;149:273-285. Hanna FWF, Issa BG, Lea SC, George C, Golash A, Firn M, Ogunmekan S, Maddock E, Sim J, Xydopoulos G, Fordham R, Fryer AA. Adrenal lesions found incidentally: how to improve clinical and cost-effectiveness. BMJ Open Quality. 2019;In press.

The frequency of testing for glycated haemoglobin, HbA1c, is linked to the probability of achieving target levels in patients with suboptimally controlled diabetes mellitus

Background We previously showed, in patients with diabetes, that >50% of monitoring tests for glycated haemoglobin (HbA1c) are outside recommended intervals and that this is linked to diabetes control. Here, we examined the effect of tests/year on achievement of commonly utilised HbA1c targets and on HbA1c changes over time. Methods Data on 20,690 adults with diabetes with a baseline HbA1c of >53 mmol/mol (7%) were extracted from Clinical Biochemistry Laboratory records at three UK hospitals. We examined the effect of HbA1c tests/year on (i) the probability of achieving targets of ≤53 mmol/mol (7%) and ≤48 mmol/mol (6.5%) in a year using multi-state modelling and (ii) the changes in mean HbA1c using a linear mixed-effects model. Results The probabilities of achieving ≤53 mmol/mol (7%) and ≤48 mmol/mol (6.5%) targets within 1 year were 0.20 (95% confidence interval: 0.19-0.21) and 0.10 (0.09-0.10), respectively. Compared with four tests/year, having one test or more than four tests/year were associated with lower likelihoods of achieving either target; two to three tests/year gave similar likelihoods to four tests/year. Mean HbA1c levels were higher in patients who had one test/year compared to those with four tests/year (mean difference: 2.64 mmol/mol [0.24%], p<0.001). Conclusions We showed that ≥80% of patients with suboptimal control are not achieving commonly recommended HbA1c targets within 1 year, highlighting the major challenge facing healthcare services. We also demonstrated that, although appropriate monitoring frequency is important, testing every 6 months is as effective as quarterly testing, supporting international recommendations. We suggest that the importance HbA1c monitoring frequency is being insufficiently recognised in diabetes management.

SAT-374 Adrenal Incidentaloma Management: Development of a Cost-Effectiveness Tool

Background: Adrenal incidentalomas (AI) are incidentally identified lesions whilst scanning for other purposes. They are mostly benign and hormonally inactive but about 20% are hormonally-active or malignant, requiring prompt intervention. The overall reported AI prevalence is 3-5% but increases with age (up to 7% of those above 70 years). The arranged investigations (hormonal work-up and further scanning) pose significant financial pressure on providers. Methods:

We developed a cost-effectiveness tool “the Adrenal Incidentaloma Intervention Cost Assessment Tool (AI₂CAT)”.

We developed a novel web-based, electronic Adrenal Incidentaloma Management System (eAIMS).

We conducted time & motion study utilising the estimated time managing an individual AI case. This was undertaken for different phases of our work: (i) pre-intervention, (ii) The implementation of case prioritisation strategy + utilisation of eAIMS and (iii) future proactive case identification and streamlining into low- and high-risk groups.

Results:

Projecting our unit’s case load to a UK-wide context, there could be 50,000 new cases PA/year.

Utilising the AI2CAT tool and the time and motion analysis data, demonstrated that introducing the eAIMS system in combination with the MDT prioritisation process (Phase 2) reduced the number of tasks required in the AI management pathway. This resulted in a reduction in the hands-on total time taken (from AI identification to MDT decision) by 48.6%.

Utilising standardised staff costs, hands-on time was reduced by 28.2% of total costs/patient.

Conclusion: We have developed an electronic management system for AI, together with a cost-effectiveness tool to measure the potential cost implications. The combined approach of using the eAIMS system together with a prioritisation strategy resulted in reduced staff hands-on time and cost per case.

SAT-372 Correlation of Serum Dexamethasone and Cortisol Concentrations Post Dexamethasone 1 Mg in the Overnight Dexamethasone Suppression Test in Patients with Unilateral and Bilateral Adrenal Incidentalomas

Background: The most common functional abnormality in adrenal incidentalomas (AI) is autonomous cortisol secretion. Most guidelines recommend a 1 mg overnight dexamethasone suppression test (ONDST) as a screening test for this abnormality. There is some evidence that simultaneous measurement of post dexamethasone serum dexamethasone (SD) with serum cortisol (SC) improves the accuracy of the ONDST. We have therefore been routinely measuring SD in our unit to ensure adequate concentrations when interpreting the results of this test. Aim: To measure the correlation between SD and SC concentrations and SD with the decrement in serum cortisol levels from baseline (9 am the day before the test) to the post dexamethasone level (DSC) in the ONDST. Method: We examined the results of 57 patients with unilateral or bilateral adrenal incidentalomas who underwent a 1 mg ONDST on our unit. Using linear regression analysis, we correlated SC and SD concentrations and serum SD concentration with the DSC. We also examined whether lower levels of SD were associated with adequate suppression of SC following ONDST. Results: SD levels range <0.3 to >16, median 7.656 nmol/L. SC range <22 to 780, median 39 nmol/L and baseline cortisol range 51 to 570, median 314 nmol/L. There was no significant correlation between SD and SC (P=0.059, R squared 0.09). There was also no significant correlation with DSC (P=0.082, R squared 0.07). However, we did note adequate suppression of SC following ONDST even when the SD levels were at the lowest measurable levels (<0.3 nmol/L). Conclusion: There does not appear to be a significant correlation between SD concentrations SC or DSC in an ONDST in patients with AI. However, this small retrospective analysis indicates that even at low levels of SD, adequate suppression of SC can be observed.

Pheochromocytomas and Hypertension

PURPOSE OF REVIEW

Pheochromocytomas and paragangliomas (PPGLs) are uncommon catecholamine-producing neuroendocrine neoplasms that usually present with secondary hypertension. This review is to update the current knowledge about these neoplasms, the pathophysiology, genetic aspects and diagnostic and therapeutic algorithms based on scientific literature mostly within the past 3 years.

RECENT FINDINGS

Eighty to eighty-five percent of PPGLs arise from the adrenal medulla (pheochromocytomas; PCCs) and the remainder from the autonomic neural ganglia (paragangliomas; PGLs). Catecholamine excess causes chronic or paroxysmal hypertension associated with sweating, headaches and palpitations, the presenting features of PPGLs, and increases the cardiovascular morbidity and mortality. Genetic testing should be considered in all cases as mutations are reported in 35-40% of cases; 10-15% of PCCs and 20-50% of PGLs can be malignant. Measurements of plasma-free metanephrines or 24-h urine-fractionated metanephrines help biochemical diagnosis with high sensitivity and specificity. Initial anatomical localization after biochemical confirmation is usually with computed tomography (CT) or magnetic resonance imaging (MRI). ¹²³Iodine metaiodobenzylguanidine (¹²³I-MIBG) scintigraphy, positron emission tomography (PET) or single-photon emission computed tomography (SPECT) is often performed for functional imaging and prognostication prior to curative or palliative surgery. Clinical and biochemical follow-up is recommended at least annually after complete tumour excision. Children, pregnant women and older people have higher morbidity and mortality risk. De-bulking surgery, chemotherapy, radiotherapy, radionuclide agents and ablation procedures are useful in the palliation of incurable disease. PPGLs are unique neuroendocrine tumours that form an important cause for endocrine hypertension. The diagnostic and therapeutic algorithms are updated in this comprehensive article.

Predicting dysglycaemia in patients under investigation for acute coronary syndrome

AIMS

To examine methods for the identification of previously undetected dysglycaemia [diabetes and impaired glucose tolerance (IGT)] in patients investigated for possible acute coronary syndrome. Specifically, we wished to examine whether the recently advocated use of glycosylated haemoglobin (HbA1c) would enhance detection rates for diabetes in these patients.

METHODS

Patients (n = 200) investigated for possible acute coronary syndrome and not previously known to have diabetes were recruited and anthropometric data collected. Random plasma glucose concentrations followed by oral glucose tolerance tests, HbA1c, fasting lipids, high sensitivity C-reactive protein and homeostatic modular assessment-insulin resistance were obtained during admission. Following discharge, the fasting plasma glucose (FPG) was repeated to determine the importance of sequential fasting levels. The accuracy of individual tests, combinations and sequential testing was assessed using receiver operating characteristic curves. A predictive index (PI) was generated using stepwise logistic regression models.

RESULTS

The prevalence of diabetes and IGT were 21 and 32%, respectively. FPG >6.0 mmol/l and HbA1c ≥ 6.0% had specificities of 94.9% and 93.6% but sensitivities of only 31.7 and 39.0%, respectively. Combination and sequential testing provided little additional benefit. Use of a PI comprising FPG, HbA1c and age provided the best overall performance (75.6% sensitivity, 77.1% specificity, negative predictive value 92.4%).

CONCLUSION

Our data confirm the high prevalence of dysglycaemia in this cohort. The commonly advocated screening tools have significant limitations if used in isolation, combination or sequentially. Our approach using a PI offers improved performance partly as it uses continuous data rather than arbitrary cut-off values.

Gestational diabetes screening and glycaemic management; national survey on behalf of the Association of British Clinical Diabetologists

BACKGROUND

There is no UK consensus for screening methodology, diagnosis and management of gestational diabetes mellitus (GDM).

AIM

To evaluate routine practice for GDM management across the UK.

METHODS

Questionnaires were sent to all members of the Association of British Clinical Diabetologists. They were asked to describe how patients were screened for GDM, the diagnostic criteria and subsequent management and clinical targets. Centres that did not respond were followed up by personal communication. Variability trends within regions were assessed.

RESULTS

The response rate averaged 46% nationally (35-67%). Most (85%) units hold a joint clinic, regardless of the size. Most (82%) centres routinely screen for GDM; half universally and half screening high risk pregnancies only. Screening tests, cut-off values, timings and subsequent action vary widely. The first screening test to be used varies, with 40% using glycosuria, followed by random plasma glucose (RPG)(28%), high risk features (11%) then FPG in 6%. Cut-off values for both random and plasma glucose as screening methods also vary. The 75 g oral glucose tolerance test (OGTT) is the most likely confirmatory test to be used if initial screening is positive; however, clinicians rely on different cut-off values and timing. Most (95%) centres routinely assess foetal growth. Postpartum screening is undertaken by 90%, using a 75 g OGTT (93%). Most (90%) centres counsel patients about their high risk for further GDM and type 2 diabetes mellitus. Variability trends in any of the responses could not be detected between different regions in the UK.

CONCLUSION

Standards for GDM screening and management vary significantly across the UK. Although most centres utilize the 75 g OGTT to confirm the diagnosis, there is no consistency in its interpretation. This survey confirms the urgent need for consensus guideline development.

Metformin, heart failure, and lactic acidosis: is metformin absolutely contraindicated?

Many patients with type 2 diabetes are denied treatment with metformin because of “contraindications” such as cardiac failure, which may not be absolute contraindications

The TSH response to domperidone reflects the biological activity of prolactin in macroprolactinaemia and hyperprolactinaemia

OBJECTIVE

To test the hypothesis that patients with hyperprolactinaemia due to biologically inactive macroprolactin will not show the characteristically increased dopaminergic inhibition of TSH release seen in patients with microprolactinomas secreting biologically active monomeric PRL.

DESIGN

Comparison of the TSH and PRL responses to dopamine antagonism with domperidone (10 mg i.v.) in patients with hyperprolactinaemia due to macroprolactinaemia or microprolactinomas.

PATIENTS

Twenty-two patients referred for the investigation of their hyperprolactinaemia were studied: 11 patients with macroprolactinaemia and 11 patients with hyperprolactinaemia due to microprolactinoma.

MEASUREMENTS

TSH and PRL levels were measured at baseline and 30 min following domperidone in both groups.

RESULTS

Patients with macroprolactinaemia showed normal TSH and PRL responses to dopamine antagonism whereas patients with microprolactinomas showed exaggerated TSH responses and reduced PRL responses. Although there was considerable overlap between the PRL responses in the two groups, there was very clear separation between the PRL/TSH response ratios (normal > 1.0) of 4.0 +/- 1.8 for the macroprolactinaemia group and 0.4 +/- 0.2 for the microprolactinoma group (P < 0.0001).

CONCLUSIONS

These data support the hypothesis that elevated circulating levels of macroprolactin, as opposed to biologically active monomeric PRL, do not exert increased positive feedback on the hypothalamic dopaminergic inhibition of TSH release.

Screening for gestational diabetes; past, present and future

Gestational diabetes is carbohydrate intolerance, with onset or first recognition of hyperglycaemia during pregnancy. Several studies have suggested that gestational hyperglycaemia is associated with adverse maternal and fetal outcomes, promoting the case for screening. Conversely, others argue that screening for gestational diabetes may colour the clinical judgement, influencing further management, e.g. more 'unjustified' caesarean sections. Additionally, the lack of definitive data either on a clear-cut glycaemic threshold for the development of adverse outcomes or on the impact of intervention is emphasized by opponents of screening. This review attempts to evaluate the available data on screening for gestational diabetes. Oral glucose tolerance test is promoted on the basis that the diabetogenic stress of pregnancy is encountered during late gestation and is best recognized in the fed state. There are different tests, including the 1 h/50-g, 2 h/75-g and 3 h/100-g tests, with practical limitations, including the time and cost involved and the unpleasant supra-physiological glucose load that is unrelated to body weight, and issues of reproducibility and sensitivity/specificity profiles. Despite its convenience, the poor sensitivity of random glucose has precluded its routine use for screening. Fasting glucose appears to be promising but further testing is required to ensure satisfactory sensitivity/specificity in different populations. Despite its limitations, the oral glucose tolerance test has become established as the 'most acceptable' diagnostic test for gestational diabetes. More convenient methods, e.g. fasting or random or post-load glucose, have to be validated therefore against the oral glucose tolerance test to gain acceptance for routine screening.

Long-term follow-up results of transsphenoidal surgery for Cushing's disease in a single centre using strict criteria for remission

OBJECTIVE

Transsphenoidal selective adenomectomy (TSA) is widely accepted as the treatment of choice for Cushing's disease but not all patients are cured by this procedure. The success of surgery depends on the skill and experience of the surgeon but the criteria used to define remission are highly variable. We have analysed the outcome following surgery in our centre using the stringent requirement of a postoperative serum cortisol of < 50 nmol/l as our definition of remission and assessed whether changes in surgical policy, including a greater emphasis on selective procedures and the move in recent years to a single surgeon undertaking all pituitary surgery, have improved complication and remission rates.

PATIENTS AND METHODS

The case notes, histology and pituitary imaging of 54 consecutive patients (42 females, mean age 41 years) with pituitary-dependent Cushing's syndrome who had undergone transsphenoidal surgery between January 1980 and November 2000 were reviewed. Follow-up was for a median of 6 years (range 6 months to 21 years).

RESULTS

One patient died within 1 week of surgery (1.9%) and major morbidity occurred in eight patients (15%). Clinical and biochemical remission was achieved in 41 patients (77%) with only two recurrences (5%) to date. Success was related to tumour size with 37 (86%) of 43 intrasellar lesions successfully resected compared with only four (40%) of 10 extrasellar adenomas. Twenty-four (59%) of those in remission developed partial or complete hypopituitarism compared with four (33%) of those not in remission. The extent of surgical exploration predicted the development of hypopituitarism (88% total hypophysectomy, 33% hemihypophysectomy, 14% selective adenomectomy) but not remission (75% total hypophysectomy, 87% hemihypophysectomy, 71% selective adenomectomy). Among complications, an excess of venous thromboembolic disease was noted, with three patients (6%) developing deep venous thrombosis or pulmonary embolism postoperatively. Comparison of the data for individual surgeons revealed an improvement in outcome over time, with 100% remission of microadenomas, 29% hypopituitarism and 12% complications following the move to a single surgeon undertaking all pituitary surgery.

CONCLUSION

Transsphenoidal surgery is a safe and effective treatment for Cushing's disease and our results compare favourably with those from published series, the majority of which comprise relatively small numbers. The presence of an intrasellar lesion and postoperative serum cortisol < 50 nmol/l are good predictors of remission in the long term but historically in our centre this can only be achieved in a significant number of patients at the expense of some degree of hypopituitarism. However, the surgical outcome for Cushing's disease, including a reduced frequency of hypopituitarism, can be improved if patients are operated on by a single pituitary surgeon, using selective adenomectomy as the preferred surgical approach wherever possible.