Post-load glucose spike: a better predictor of post-MI prognosis than post-load glucose in patients without known diabetes

Funding Acknowledgements

Type of funding sources: None.

Background

In non-diabetic population, number of deaths increase as the post-challenge glucose spike (PGS) i.e. difference between the fasting and 2h-PG increases in the DECODE study.

Purpose

To assess whether PGS is a better predictor of post-ACS prognosis in patients without known diabetes.

Methods

Retrospective cohort analysis of post-MI survivors (n=1056) without known diabetes undergoing pre-discharge oral glucose tolerance test. A standardised dataset was collected for the Myocardial Infarction National Audit Project. MACE (death or non-fatal re-infarction) over 5 (median 3.4) years was collected from notes review. Predictors of MACE were determined from Cox proportional hazard regression (stepwise) models adjusted for several variables (tested for collinearity) including GRACE score (GRS), fasting (FG) and 2-hour post-load glucose (2hG) and PGS as % of the 2hG (%PGS) (VIF=3.12). Incremental predictive value of PGS over 2hG was tested using probabilities of MACE calculated from logistic regression models using the same covariates and FG, 2hG and PGS individually and in combination applying c-statistics, continuous net reclassification improvement (cNRI) and integrated discrimination improvement (IDI).

Results

Of the patients 469 (44.4%) had normal glucose tolerance, 378(35.8%) preDM and 209 (19.8%) had new DM. In the whole cohort, MACE was predicted by %PGS (HR 1.02 (1.01-1.03), p<0.0001), GRS (HR 1.01, (1.01-1.02), p<0.0001), discharge with betablockers (HR 1.50 (1.14-1.98), p=0.0037), previous history of MI (HR 1.44 (1.02-2.03), p=0.039) but neither FG nor 2hG were included in the final model. MACE was predicted by %PGS (HR 1.04 (1.02-1.06), p<0.0001) in the non-diabetic group but not in the new DM patients (HR 1.02 (0.99-1.05), p=0.296). Addition of PGS to models containing FG and 2hG improved reclassification by 22.6% for events and 5.0% for non-events (NRI>0 0.275, p<0.001) and discrimination (IDI 0.0076, p=0.033). However the c-statistics did not change significantly (ΔAUC 0.0094, p=0.099).

Conclusion

PGS is a better predictor of post-MI prognosis than FG or 2hG in patients without known diabetes.

Post-load glucose spike is a determinant of post-MI prognosis in patients without known or newly diagnosed diabetes

Background

Post-prandial plasma glucose spikes contribute to the progression of atherosclerosis. Glycaemic variability may predict post-ACS prognosis. A third to two-thirds of these patients had diabetes mellitus (DM). Post-ACS prognosis is worse in DM than in those without. This has not been tested in patients without DM.

Purpose

To test whether post-load spike in plasma glucose in patients without known or newly diagnosed DM adversely affects prognosis.

Methods

Retrospective cohort analysis of 847 MI survivors without known or newly diagnosed DM who were followed up for MACE (death and non-fatal MI). The median post-glucose spike (PGS, defined as the difference between the 2h-PG and FPG) was 2.4 mmol/l for the whole cohort and 1.5 mmol/l for the patients with normal glucose tolerance (NGT). Group 1: PGS ≤2.4 mmol/l and Group 2: PGS >2.4 mmom/l were compared using Mann-Whitney test for continuous variables and chi-squared test for categorical variables. Event free survival in the two groups was estimated from the Kaplan–Meier curves and compared using log-rank test. Cox proportional hazard regression identified predictors of MACE. Continuous net reclassification improvement (NRI>0) and integrated discrimination improvement (IDI) and c-statistics determined the added predictive value of glycaemic matrices

Results

MACE was higher in group 2 (OR 1.99, 95% CI 1.36 to 2.91, p=0.0004) compared to group 1. In patients with NGT, MACE was higher in patients with PGS ≥1.5 mmol/l vs those below (OR 2.37, 95% CI 1.31 to 4.26, p=0.0041). Event free survival was worse in pre-diabetes than in the NGT groups (HR 1.57, 95% CI 1.17 to 2.12, p=0.003). and in group 2 than 1 (HR 2.01, 95% CI 1.49 to 2.71, p<0.001). Amongst the patients with NGT, event free survival was worse in patients with PGS ≥1.5 mmol/l (HR 2.09, 95% CI 1.35 to 3.25, p<0.001). PGS independently predicted MACE in the whole cohort (HR 1.16, 95% CI 1.06 to 1.26, p=0.002) and NGT group (HR 2.06, 95% 1.51 to 2.79, p<0.000). Group 2 independently predicted MACE in the whole cohort (HR 1.75, 95% CI 1.26 to 2.42, p<0.001). In the NGT group, PGS >median, independently predicted of MACE (HR 2.67, 95% CI 1.54 to 4.61, p<0.001). The c-statistic a model containing GRS only increased on addition of PGS (δAUC 0.0134, p=0.046) but not on addition of FPG. Within the whole cohort, PGS improved the net reclassification by 28% when added to the model containing GRS only. NGT cohort had higher net improvement at 46.6%. Addition of PGS to the model containing GRS and FPG resulted in NRI>0 of 25.5% in the whole cohort and 56.3% in the NGT cohort. Similar changes were seen in the IDI.

Conclusion(s)

PGS predicts post MI prognosis in patients without known or newly diagnosed DM including in patients with NGT. This suggests that PGS is a more powerful indicator of post-MI prognosis than FPG

Funding Acknowledgement

Type of funding source: None

Does high-normal 2-hour post load plasma glucose after myocardial infarction in patients with normal glucose tolerance adversely affect prognosis?

Background

Type 2 diabetes mellitus (DM) and pre-DM, newly diagnosed after MI in patients without known DM adversely affects prognosis. 2-hour post-load glucose (2h-PG) predicts post-MI prognosis better than fasting plasma glucose (FPG). Plasma glucose below the conventional threshold for the diagnosis of impaired fasting glucose (IFG) and impaired glucose tolerance (IGT), affects post-MI prognosis.

Purpose

To test whether high-normal post-load plasma glucose in patients with normal glucose tolerance (NGT) would affect post-MI prognosis and whether FPG or 2h-PG increases this risk.

Methods

Retrospective cohort analysis of 425 MI survivors without known DM and with NGT followed up for (death and non-fatal MI) as MACE. MACE in patients with 2h-PG > median for the whole cohort (Group 2), was compared with those at or below (Group 1). Event free survival in the two groups was estimated from the Kaplan–Meier curves and compared using log-rank test. Cox proportional hazard regression identified predictors of MACE. Continuous net reclassification improvement (NRI>0) and integrated discrimination improvement (IDI) and c-statistics determined the added predictive value of glycaemic matrices.

Results

Median 2h-PG was 6.3 mmol/l. 219 patients in Group 1 and 206 in Group 2. Group 2 had higher age, prevalence of hypertension, hypercholesterolaemia, ST-segment depression and higher heart rate and GRACE scores. Median follow-up was 40.6 months. MACE was more frequent in Group 2 than Group 1 (OR 2.82, 95% CI 1.55 to 5.16, p<0.001). MACE-free survival was higher in Group 1 (HR 2.43, 95% CI 1.53 to 3.85, p<0.001). Group 2 (HR 2.42, 95% CI 1.44 to 4.04, p<0.001) predicted the MACE-free survival. 2h-PG, but not the FPG independently predicted of MACE (HR 1.73, 95% CI 1.31 to 2.30, p<0.001). Addition of 2h-PG to models containing FPG and other variables improved their predictive performance (NRI>0 0.5062, p<0.001; IDI 0.0376, p=0.003). The c-statistic increased when 2h-PG was added to the GRACE score only model (δAUC 0.037, 95% CI 0.012 to 0.081, p=0.046).

Conclusion(s)

This study suggests that “high-normal” 2h-PG is an independent predictor of post-MI prognosis. Normoglycaemic patients with 2h-PG ≥6.4 mmol/l, had worse post-MI prognosis compared to those with 2h-PG ≤6.3 mmol/l. The risk of MACE increased with increasing 2h-PG within the normal range. FPG had no effect on prognosis.

Funding Acknowledgement

Type of funding source: None

Soy isoflavones improve cardiovascular disease risk markers in women during the early menopause

BACKGROUND

Hormone replacement therapy may be beneficial for cardiovascular disease risk (CVR) in post-menopausal women. Soy isoflavones may act as selective estrogen receptor modulators. The aim of this study was to evaluate whether soy isoflavones had an effect on CVR markers.

METHODS

The expected 10-year risk of cardiovascular disease and mortality were calculated as a secondary endpoint from a double blind randomised parallel study involving 200 women (mean age 55 years, Caucasian, Hull, UK, 2012) in the early menopause who were randomised to 15 g soy protein with 66 mg isoflavone (SPI) or 15 g soy protein alone (depleted of all isoflavones; SP) given as a snack bar between meals daily for 6 months. Age, diabetes, smoking, blood pressure and lipid profiles were used to calculate CVR using the Framingham CVR engine.

RESULTS

SPI treatment resulted in a significant reduction in the metabolic parameters and systolic blood pressure compared to SP (p < 0.01). There were no changes in fasting lipid profile and diastolic blood pressure with either treatment. At 6 months, changes in these parameters with SPI treatment were reflected in a calculated 27% (p < 0.01) reduction in 10 year coronary heart disease risk, a 37% (p < 0.01) reduction in myocardial infarction risk, a 24% (p < 0.04) reduction in cardiovascular disease and 42% (p < 0.02) reduction in cardiovascular disease death risk.

CONCLUSIONS

Supplementation with soy protein with isoflavones for 6 months significantly improved CVR markers and calculated CVR at 6 months during early menopause compared to soy protein without isoflavones.

ISRCTN REGISTRY

ISRCTN34051237.

The repeatability of the abbreviated (4-h) Oral Fat Tolerance Test and influence of prior acute aerobic exercise

PURPOSE

The Oral Fat Tolerance Test (OFTT) is regarded as a repeatable measure used to assess postprandial triglyceride (TAG) levels, with higher levels observed in cardio-metabolic disorders. Acute aerobic exercise intervention before OFTT reduces the TAG response, but the repeatability of this effect is unknown. The aim of this study was to determine the repeatability of the abbreviated 4-h OFTT with and without immediate prior aerobic exercise.

METHODS

On four separate days, healthy adult male participants underwent two 4-h OFTT (n = 10) and another two 4-h OFTT with 1-h of standardised moderate intensity aerobic exercise performed immediately before meal ingestion (n = 11). The OFTT meal composition included 75.4 g total fat, 21.7 g carbohydrate and 13.7 g protein. Venous blood was sampled at baseline and hourly up to 4 h after the OFTT meal ingestion, and TAG area under the curve (AUC) was calculated.

RESULTS

Nonparametric Bland-Altman analysis of 4-h TAG AUC revealed that 9 of 10 repeat measurements fell within ±15 % of the median TAG AUC for the OFTT. By contrast, two of 11 repeat measurements fell within ±15 % of the median TAG AUC for the OFTT undertaken with 1-h prior aerobic exercise.

CONCLUSIONS

The 4-h OFTT is a repeatable test of postprandial TAG responses in healthy men. However, aerobic exercise performed immediately before OFTT considerably increases the variability of TAG AUC. These findings have implications for interpretation of research studies investigating exercise intervention performed immediately before OFTT. Future studies should also investigate the repeatability of exercise performed 8-24 h before OFTT.

Effects of human recombinant growth hormone on exercise capacity, cardiac structure, and cardiac function in patients with adult-onset growth hormone deficiency

Objective

Epidemiological studies suggest that adult-onset growth hormone deficiency (AGHD) might increase the risk of death from cardiovascular causes.

Methods

This was a 6-month double-blind, placebo-controlled, randomised, cross-over trial followed by a 6-month open-label phase. Seventeen patients with AGHD received either recombinant human growth hormone (rGH) (0.4 mg injection daily) or placebo for 12 weeks, underwent washout for 2 weeks, and were then crossed over to the alternative treatment for a further 12 weeks. Cardiac magnetic resonance imaging, echocardiography, and cardiopulmonary exercise testing were performed at baseline, 12 weeks, 26 weeks, and the end of the open phase (12 months). The results were compared with those of 16 age- and sex-matched control subjects.

Results

At baseline, patients with AGHD had a significantly higher systolic blood pressure, ejection fraction, and left ventricular mass than the control group, even when corrected for body surface area. Treatment with rGH normalised the insulin-like growth factor 1 concentration without an effect on exercise capacity, cardiac structure, or cardiac function.

Conclusion

Administration of rGH therapy for 6 to 9 months failed to normalise the functional and structural cardiac differences observed in patients with AGHD when compared with a control group.

Increased expression of circulating miRNA-93 in women with polycystic ovary syndrome may represent a novel, non-invasive biomarker for diagnosis

MicroRNAs (miRNA) are a novel class of small noncoding single-stranded RNA molecules that regulate gene expression. There is increasing evidence of their importance in polycystic ovary syndrome (PCOS). The objective was to determine if miRNA-93 and miRNA-223 are differentially expressed in the circulation of women with PCOS compared to age matched women. A case-control study comparing women with PCOS (n = 25) to age and weight matched controls (n = 24) without PCOS was performed. MiRNA-93 and miRNA-223 were determined by total RNA reverse transcription. Both miRNA-93 and miRNA-223 were significantly increased relative to the control group (p < 0.01, p = 0.029 respectively). In both groups there was no correlation of either miRNA-93 or miRNA-223 with insulin, HOMA-IR, HOMA-β or testosterone levels. The area under the receiver operator characteristic curve for miR-223 and miR-93 was 0.66 and 0.72 respectively, suggesting miR-93 is a more efficient biomarker than miR-223 for diagnosis of PCOS. The combination of the two miRNAs together, tested using multiple logistic regression analysis, did not improve the diagnostic potential. In conclusion, circulating miRNA-93 and miRNA-223 were higher in women with PCOS compared to age and weight matched controls independent of insulin resistance and testosterone levels, and miR-93 may represent a novel diagnostic biomarker for PCOS.

LDL cholesterol variability in patients with Type 2 diabetes taking atorvastatin and simvastatin: a comparison of two formulae for LDL-C estimation

Background

A new formula was recently proposed by Cordovo et al. that was more highly correlated with low-density lipoprotein (LDL) measured directly than the Friedewald LDL formula. We conducted this prospective study to establish whether the new formula allows true variations in LDL within the same individual to be tracked more closely than that of the Friedewald formula.

Methods

A cross-over study of biological variation of lipids in 26 patients with Type 2 diabetes (T2DM) taking either a short half-life statin, simvastatin 40 mg ( n = 10), or a long half-life statin, atorvastatin 10 mg. After three months on one statin, fasting lipids were measured on 10 occasions over a five-week period. The same procedure was then followed for the other statin. The LDL was measured by a direct LDL immunoassay and was compared to the LDL estimated by the Friedewald and Cordova (0.7516) × (total cholesterol [TC]−high-density lipoprotein cholesterol [HDL-C]) formulae.

Results

As a group, the calculated or measured mean LDL was no different between statins. However, the biological coefficient of variation (CV) of directly measured LDL was far larger with simvastatin than atorvastatin. This difference was detected by Cordova LDL but not found with the Friedewald LDL formula.

Conclusions

In contrast to Friedewald LDL, Cordova LDL estimation revealed LDL to be much more stable in T2DM patients taking atorvastatin rather than simvastatin that was in accord with LDL when measured directly. Therefore, Cordova LDL which is a measure of non-HDL-cholesterol is the simplest, cheapest and the most convenient measurement for assessment of response to statin treatment.

Biological variation of cardiovascular risk factors in patients with diabetes

Biological variation refers to the natural fluctuations found when repeated measurements are made in a biological system. Generally, biological variation remains within narrow boundaries in health, but may differ in pathological states, with implications for the diagnosis and monitoring of disease processes. In disease, biological variation may alter such that any subsequent measurement may need to have a greater difference compared with a healthy control to be biologically relevant. Treatments such as insulin or anti-hypertensive therapy have been shown to reduce biological variability closer to normal levels and theoretically this may help prevent complication development or progression in conditions such as diabetes. This article reviews how biological variation can influence our identification and assessment of vascular risk factors in a person with diabetes. The role of biological variation in the diagnosis of diabetes (glucose and HbA1c) is then examined. Finally, the influence that common treatments in diabetes have in modifying biological variation is described.

The effect of atorvastatin and simvastatin on vitamin D, oxidative stress and inflammatory marker concentrations in patients with type 2 diabetes: a crossover study

The pleiotropic effect of statins may be mediated in part through raising 25 hydroxy vitamin D (25OHD) concentrations. It has also been shown that an increase in oxidative stress and inflammatory markers are a feature of the patients with type 2 diabetes (T2DM). A cross-over study of 26 patients with T2DM taking either simvastatin 40 mg or atorvastatin 10 mg was undertaken. After 3 months on one statin, lipids, C-reactive protein (hsCRP), 25OHD and malondialdehyde (MDA) were measured repeatedly. The same procedure was then followed taking the other statin. Despite similar lipid-lowering, the mean 25OHD was higher on atorvastatin compared with simvastatin and the mean MDA and hsCRP levels lower, irrespective of which statin the patients were taking before crossover. The changes in 25OHD predicted changes in CRP and MDA levels. Thus, compared with simvastatin, atorvastatin shows apparently beneficial pleiotropic effects with respect to 25OHD concentrations as well as markers of oxidative stress and inflammation in patients with T2DM.

Recent advances in cardiovascular aspects of polycystic ovary syndrome

Polycystic ovary syndrome (PCOS) has been associated with increased cardiovascular risk (CVR) markers, but population studies have not clarified whether there is an increase in cardiovascular morbidity and mortality. Four different PCOS phenotypes resulted from the Rotterdam criteria that may differ in their CVR potential, thus introducing further complexity. This has led to studies using surrogate CVR markers including biomarkers in blood and imaging such as flow-mediated vasodilatation. In PCOS, both peripheral and central insulin resistance (IR) have been shown. Weight loss has been shown to improve IR and visceral fat, while insulin sensitizer therapies with metformin or thiazolidinediones improve IR and endothelial dysfunction. IR is also found in non-alcoholic fatty liver disease that in turn is very common in PCOS; studies have suggested that IR may be improved by treatment with metformin and omega-3 fish oils. PCOS patients have a more dyslipidemic phenotype that is worse in 'classical PCOS' associated with a higher CVR. Studies with atorvastatin and simvastatin have reported a decrease in the lipid parameters and an improvement in CVR indices including IR, but it is unclear whether this is due to their lipid-lowering action or a pleiotropic effect of the statin. In this expert opinion review, the relevant literature published during the last 2 years was considered. It focuses on some recent important data that has emerged while also exposing the gaps that remain in our knowledge that need to be addressed.

Safety, efficacy and tolerability of exenatide in combination with insulin in the Association of British Clinical Diabetologists nationwide exenatide audit*

AIM

To assess the extent, safety, efficacy and tolerability of reported off-licence exenatide use through a nationwide audit.

METHODS

The Association of British Clinical Diabetologists hosted a password-protected, online collection of anonymized data of exenatide use in real clinical practice. Three hundred and fifteen contributors from 126 centres across UK provided data on 6717 patients. HbA1c and weight changes, exenatide discontinuation, adverse events and treatment satisfaction were compared between non-insulin and insulin-treated patients.

RESULTS

Four thousand eight hundred and fifty-seven patients had baseline and follow-up treatment status with mean (±s.d.) baseline HbA1c 9.45 ± 1.69% and BMI 40.0 ± 8.2 kg/m(2) . Of the 4857 patients, 1921 (39.6%) used exenatide with insulin. Comparing patients who continued insulin with exenatide with non-insulin-treated patients, mean (±s.e.) latest HbA1c and weight reduction (median 26 weeks) were 0.51 ± 0.06 versus 0.94 ± 0.04% (p < 0.001) and 5.8 ± 0.2 versus 5.5 ± 0.1 kg (p = 0.278). Insulin-treated patients had higher rates of exenatide discontinuation (31.0 vs. 13.9%, p < 0.001), hypoglycaemia (8.9 vs. 6.1%, p < 0.001), gastrointestinal side effects (28.4 vs. 25.0%, p = 0.008) and treatment dissatisfaction (20.8 vs. 5.7%, p < 0.001). However, 34.2% of the patients continuing insulin still achieved HbA1c reduction ≥1%. There was significant insulin discontinuation, dose reduction and greater sulphonylurea discontinuation among insulin-treated patients.

CONCLUSIONS

Addition of exenatide to obese, insulin-treated patients can improve glycaemia and weight. Adverse events were statistically but probably not clinically significantly higher, but combination treatment was less well tolerated. Overall, exenatide was less effective in lowering HbA1c among insulin-treated patients, although significant number of insulin-treated patients still achieved significant HbA1c, weight and insulin reductions. Further research into identifying obese, insulin-treated patients who will tolerate and benefit from exenatide treatment is urgently needed.

Response at 3 months to insulin dose decisions made at exenatide initiation in the Association of British Clinical Diabetologists (ABCD) nationwide exenatide audit

It is uncertain what should be done with insulin dose if starting exenatide. In the ABCD nationwide exenatide audit, many patients with type 2 diabetes had worsened glycaemia when insulin was stopped. If starting exenatide, insulin should not be stopped but weaned off only if there is significant glycaemic response.

Is there a role for immune and anti-in-flammatory therapy in type 2 diabetes?

There is a growing body of evidence to suggest that type 2 diabetes is associated with a generalised activation of the innate immune system, in which there is a chronic low-grade inflammation. Further evidence for roles of inflammation in type 2 diabetes comes from clinical studies using either anti-inflammatory approaches or biological agents that target specific proinflammatory cytokine pathways to improve parameters of glucose control especially with IL-1β (Interleukin 1 β) antagonism and salsalate (non-acetylated prodrug of salicylate) treatment. In this review, recent evidence implicating the pathological involvement of the immune system in type 2 diabetes is examined, together with the role of potential treatment modalities targeting the immune system in the management of type 2 diabetes.

High-cocoa polyphenol-rich chocolate improves HDL cholesterol in Type 2 diabetes patients

AIM

To examine the effects of chocolate on lipid profiles, weight and glycaemic control in individuals with Type 2 diabetes.

METHODS

Twelve individuals with Type 2 diabetes on stable medication were enrolled in a randomized, placebo-controlled double-blind crossover study. Subjects were randomized to 45 g chocolate with or without a high polyphenol content for 8 weeks and then crossed over after a 4-week washout period. Changes in weight, glycaemic control, lipid profile and high-sensitivity C-reactive protein were measured at the beginning and at the end of each intervention.

RESULTS

HDL cholesterol increased significantly with high polyphenol chocolate (1.16 ± 0.08 vs. 1.26 ± 0.08 mmol/l, P = 0.05) with a decrease in the total cholesterol: HDL ratio (4.4 ± 0.4 vs. 4.1 ± 0.4 mmol/l, P = 0.04). No changes were seen with the low polyphenol chocolate in any parameters. Over the course of 16 weeks of daily chocolate consumption neither weight nor glycaemic control altered from baseline.

CONCLUSION

High polyphenol chocolate is effective in improving the atherosclerotic cholesterol profile in patients with diabetes by increasing HDL cholesterol and improving the cholesterol:HDL ratio without affecting weight, inflammatory markers, insulin resistance or glycaemic control.

Low density lipoprotein-cholesterol variability in patients with type 2 diabetes taking atorvastatin compared to simvastatin: justification for direct measurement?

AIM

The benefit of direct, as opposed to calculated, low density lipoprotein -cholesterol (LDL-C) measurement remains unclear. This study compared the biological variability of direct LDL in patients with type 2 diabetes (T2DM) on equivalent doses of the short half-life statin, simvastatin or the longer half-life statin, atorvastatin.

METHODS

A cross-over study of biological variation of lipids in 26 patients with T2DM taking either simvastatin 40 mg (n = 10) or atorvastatin 10 mg. After 3 months on one statin, fasting lipids were measured on 10 occasions over a 5-week period. The same procedure was then followed on the other statin. The variability of LDL-C was established using a Beckman direct assay.

RESULTS

As a group, mean LDL was no different between statins (mean +/- s.d.) (1.69 +/- 0.60 mmol/l simvastatin vs. 1.67 +/- 0.60 mmol/l atorvastatin, p = 0.19). However, in all patients, the intraindividual biological variability of LDL while taking simvastatin was markedly higher than with atorvastatin (average s.d. = 0.17 mmol /l simvastatin vs. 0.01 mmol/l, p < 0.0001). Friedewald calculated LDL variability was no different between statins (average s.d. = 0.34 mmol /l simvastatin vs. 0.21 mmol/l atorvastatin, p = 0.19).

CONCLUSIONS

In contrast to calculated values, direct measurement revealed LDL to be much more stable (the s.d. being an order of magnitude) in T2DM patients taking atorvastatin rather than simvastatin. This means LDL targets can be consistently met with less lipid monitoring using atorvastatin rather than simvastatin. Direct LDL measurement may therefore have a particular role in monitoring patients on statin treatment.

Obesity and gestational diabetes

The prevalence of both obesity and gestational diabetes mellitus (GDM) is increasing worldwide. GDM affects about 7% of all pregnancies and is defined as any degree of impaired glucose tolerance during gestation. The presence of obesity has a significant impact on both maternal and fetal complications associated with GDM. These complications can be addressed, at least in part, by good glycaemic control during pregnancy. The significance and impact of obesity in women with GDM are discussed in this article, together with treatment options, the need for long-term risk modification and postpartum follow-up.

Effect of long-term, high-dose estrogen treatment on prolactin levels: a retrospective analysis

BACKGROUND

Exogenous estrogen administration causes prolactinoma formation in rats and there are anecdotal reports of estrogen treatment and prolactinoma formation in human transsexuals with male-to-female gender reassignment. It remains unclear whether chronic exposure to high-dose estrogen in women is linked with hyperprolactinemia. Aim The aim of this study was to determine whether high-dose, long-term subcutaneous estrogen treatment affected prolactin and gonadotropin levels.

DESIGN

This was a retrospective, observational and descriptive analysis of 101 women treated for up to 15 years following a combined hysterectomy and oophorectomy.

METHOD

A total of 101 women who were receiving estradiol implants 50-100 mg 4-6 monthly, on demand for 5-15 years following abdominal hysterectomy and bilateral salphingo-oophorectomy were studied. The main outcome measures were levels of serum prolactin, follicle stimulating hormone (FSH) and luteinizing hormone (LH). Results The 101 patients received an average cumulative estrogen dose of (mean +/- SEM) 1239 +/- 12 mg per person, 18.96 +/- 1.2 mg/kg body weight, over a period of 5-15 years. The trough estradiol levels after withholding implants for 6 months were high (1047.9 +/- 52 pmol/l). Their average prolactin level of 88.88 +/- 9.2 mU/l was normal and their FSH (1.96 +/- 0.42 IU/l) and LH (2.97 +/- 0.88 IU/l) levels were relatively suppressed.

CONCLUSION

These data are reassuring that, even in women exposed to very high doses of estrogen for a prolonged period of time, hyperprolactinemia is unlikely to occur.

Variability of lipids in patients with Type 2 diabetes taking statin treatment: implications for target setting

AIMS

To determine the biological variability of lipids in patients with Type 2 diabetes (T2DM) who are on statin treatment and then to assess any implications for current lipid targets.

METHODS

A cross-over study of biological variation of lipids in 26 patients with T2DM taking either simvastatin 40 mg or atorvastatin 10 mg. After 3 months on one statin, fasting lipids were measured on 10 occasions over a 5-week period. Following 3 months on the other statin, 10 further samples were taken over 5 weeks. The main outcome measures were biological variability of total cholesterol (TC), low-density lipoprotein (LDL) cholesterol, high-density lipoprotein (HDL) cholesterol and triglycerides.

RESULTS

The coefficient of variation (CV) of TC, LDL, HDL and triglycerides on simvastatin was 8.17, 13.11, 7.95 and 12.06%, respectively, whereas the CV on atorvastatin was 6.92, 10.30, 5.13 and 19.71%, respectively, with no statistically significant differences between statins. Treating to sustain a target TC < 5.0 mmol/l or LDL < 3.0 mmol/l means needing to maintain a mean TC of 4.3-4.4 mmol/l or LDL of 2.4-2.5 mmol/l. Treating to consistently achieve an LDL < 2.0 mmol/l means aiming for a mean of only 1.5-1.6 mmol/l.

CONCLUSION

In patients with T2DM taking either simvastatin or atorvastatin, the mean TC and LDL concentrations needed to consistently remain below a target are much lower than the target value itself. This means that guideline target limits extrapolated from the mean values of patients participating in clinical studies may overestimate the lipid reductions required.