Different intensities of glycaemic control for pregnant women with pre-existing diabetes

Different intensities of glycaemic control for pregnant women with pre-existing diabetes

BACKGROUND

The optimal glycaemic control target in pregnant women with pre-existing diabetes is unclear, although there is a clear link between high glucose concentrations and adverse birth outcomes.

OBJECTIVES

To assess the effects of different intensities of glycaemic control in pregnant women with pre-existing type 1 or type 2 diabetes.

SEARCH METHODS

We searched the Cochrane Pregnancy and Childbirth Group's Trials Register (31 January 2016) and planned to search reference lists of retrieved studies.

SELECTION CRITERIA

We included randomised controlled trials comparing different glycaemic control targets in pregnant women with pre-existing diabetes.

DATA COLLECTION AND ANALYSIS

Two review authors independently assessed trials for inclusion, conducted data extraction, assessed risk of bias and checked for accuracy. We assessed the quality of the evidence using the GRADE approach.

MAIN RESULTS

We included three trials, all in women with type 1 diabetes (223 women and babies). All three trials were at high risk of bias due to lack of blinding, unclear methods of randomisation and selective reporting of outcomes. Two trials compared very tight (3.33 to 5.0 mmol/L fasting blood glucose (FBG)) with tight-moderate (4.45 to 6.38 mmol/L) glycaemic control targets, with one trial of 22 babies reporting no perinatal deaths orserious perinatal morbidity (evidence graded low for both outcomes). In the same trial, there were two congenital anomalies in the very tight, and none in the tight-moderate group, with no significant differences in caesarean section between groups (risk ratio (RR) 0.92, 95% confidence interval (CI) 0.49 to 1.73; evidence graded very low). In these two trials, glycaemic control was not significantly different between the very tight and tight-moderate groups by the third trimester, although one trial of 22 women found significantly less maternal hypoglycaemia in the tight-moderate group.In a trial of 60 women and babies comparing tight (≤ 5.6 mmol/L FBG); moderate (5.6 to 6.7 mmol/L); and loose (6.7 to 8.9 mmol/L) glycaemic control targets, there were two neonatal deaths in the loose and none in the tight or moderate groups (evidence graded very low). There were significantly fewer women with pre-eclampsia (evidence graded low), fewer caesarean sections (evidence graded low) and fewer babies with birthweights greater than 90th centile (evidence graded low) in the combined tight-moderate compared with the loose group.The quality of the evidence was graded low or very low for important outcomes, because of design limitations to the studies, the small numbers of women included, and wide confidence intervals crossing the line of no effect. Many of the important outcomes were not reported in these studies.

AUTHORS' CONCLUSIONS

In a very limited body of evidence, few differences in outcomes were seen between very tight and tight-moderate glycaemic control targets in pregnant women with pre-existing type 1 diabetes, including actual glycaemic control achieved. There is evidence of harm (increased pre-eclampsia, caesareans and birthweights greater than 90th centile) for 'loose' control (FBG above 7 mmol/L). Future trials comparing interventions, rather than glycaemic control targets, may be more feasible. Trials in pregnant women with pre-existing type 2 diabetes are required.

Glycemic Allostasis during Mental Activities on Fasting in Non-alcohol Users and Alcohol Users with Different Durations of Abstinence

Glycemic allostasis is the process by which blood glucose stabilization is achieved through the balancing of glucose consumption rate and release into the blood stream under a variety of stressors. This paper reviews findings on the dynamics of glycemic levels during mental activities on fasting in non-alcohol users and alcohol users with different periods of abstinence. Referred articles for this review were searched in the databases of PubMed, Scopus, DOAJ and AJOL. The search was conducted in 2013 between January 20 and July 31. The following keywords were used in the search: alcohol action on glycemia OR brain glucose OR cognitive functions; dynamics of glycemia, dynamics of glycemia during mental activities; dynamics of glycemia on fasting; dynamics of glycemia in non-alcohol users OR alcohol users; glycemic regulation during sobriety. Analysis of the selected articles showed that glycemic allostasis during mental activities on fasting is poorly regulated in alcohol users even after a long duration of sobriety (1-4 weeks after alcohol consumption), compared to non-alcohol users. The major contributor to the maintenance of euglycemia during mental activities after the night's rest (during continuing fast) is gluconeogenesis.

Dichotomisation of a continuous outcome and effect on meta-analyses: illustration of the distributional approach using the outcome birthweight

BACKGROUND

Power and precision are greater in meta-analyses than individual study analyses. However, dichotomisation of continuous outcomes in certain studies poses a problem as estimates from primary studies can only be pooled if they have a common outcome. Meta-analyses may include pooled summaries of either or both the continuous and dichotomous forms, and potentially have a different combination of studies for each depending on whether the outcome was dichotomised in the primary studies or not. This dual-outcome issue can lead to loss of power and/or selection bias. In this study we aimed to illustrate how dichotomisation of a continuous outcome in primary studies may result in biased estimates of pooled risk and odds ratios in meta-analysis using secondary analyses of published meta-analyses with the outcome, birthweight, which is commonly analysed both as continuous, and dichotomous (low birthweight: birthweight < 2,500 g).

METHODS

Meta-analyses published in January 2010 - December 2011 were obtained using searches in PubMed, Embase, Web of Science, and Cochrane Database of Systematic Reviews with the outcome birthweight. We used a distributional method to estimate the pooled odds/risk ratio of low birthweight and its standard error as a function of the data reported in the primary studies of the included meta-analyses where accessible.

RESULTS

Seventy-six meta-analyses were identified. Thirty-seven percent (28/76) of the meta-analyses reported only the dichotomous form of the outcome while 26% (20/76) reported only the continuous form. In one meta-analysis (1/76), birthweight was analysed as continuous for one intervention and as binary for another and 36% (27/76) presented both dichotomous and continuous birthweight summaries. In meta-analyses with a continuous outcome, primary studies data were accessible in 39/48 and secondary analyses using the distributional approach provided consistent inferences for both the continuous and distributional estimates in 38/39.

CONCLUSION

The distributional method applied in primary studies allows both a continuous and dichotomous outcome to be estimated providing consistent inferences. The use of this method in primary studies may restrict selective outcome bias in meta-analyses.

Type 1 diabetes, diabetic nephropathy, and pregnancy: a systematic review and meta-study

BACKGROUND

In the last decade, significant improvements have been achieved in maternal-fetal and diabetic care which make pregnancy possible in an increasing number of type 1 diabetic women with end-organ damage. Optimal counseling is important to make the advancements available to the relevant patients and to ensure the safety of mother and child. A systematic review will help to provide a survey of the available methods and to promote optimal counseling.

OBJECTIVES

To review the literature on diabetic nephropathy and pregnancy in type 1 diabetes.

METHODS

Medline, Embase, and the Cochrane Library were scanned in November 2012 (MESH, Emtree, and free terms on pregnancy and diabetic nephropathy). Studies were selected that report on pregnancy outcomes in type 1 diabetic patients with diabetic nephropathy in 1980-2012 (i.e. since the detection of microalbuminuria). Case reports with less than 5 cases and reports on kidney grafts were excluded. Paper selection and data extraction were performed in duplicate and matched for consistency. As the relevant reports were highly heterogeneous, we decided to perform a narrative review, with discussions oriented towards the period of publication.

RESULTS

Of the 1058 references considered, 34 fulfilled the selection criteria, and one was added from reference lists. The number of cases considered in the reports, which generally involved single-center studies, ranged from 5 to 311. The following issues were significant: (i) the evidence is scattered over many reports of differing format and involving small series (only 2 included over 100 patients), (ii) definitions are non-homogeneous, (iii) risks for pregnancy-related adverse events are increased (preterm delivery, caesarean section, perinatal death, and stillbirth) and do not substantially change over time, except for stillbirth (from over 10% to about 5%), (iv) the increase in risks with nephropathy progression needs confirmation in large homogeneous series, (v) the newly reported increase in malformations in diabetic nephropathy underlines the need for further studies.

CONCLUSIONS

The heterogeneous evidence from studies on diabetic nephropathy in pregnancy emphasizes the need for further perspective studies on this issue.

Different intensities of glycaemic control for pregnant women with pre-existing diabetes

BACKGROUND

The optimal glycaemic control target in pregnant women with pre-existing diabetes is unclear, although there is a clear link between high glucose concentrations and adverse birth outcomes.

OBJECTIVES

To assess the effects of different intensities of glycaemic control in pregnant women with pre-existing type 1 or type 2 diabetes.

SEARCH METHODS

We searched the Cochrane Pregnancy and Childbirth Group's Trials Register (30 April 2012).

SELECTION CRITERIA

We included randomised controlled trials comparing different glycaemic control targets in pregnant women with pre-existing diabetes.

DATA COLLECTION AND ANALYSIS

Two review authors assessed trial eligibility and risk of bias, and extracted data.

MAIN RESULTS

We included three trials all in women with type 1 diabetes (223 women and babies), and all with a high risk of bias. Two trials compared very tight (3.33 to 5.0 mmol/L fasting blood glucose (FBG)) with tight-moderate (4.45 to 6.38) glycaemic control targets, with one trial of 22 babies reporting no perinatal deaths or serious perinatal morbidity. In the same trial, there were two birth defects in the very tight and none in the tight-moderate group with no significant differences in caesarean section between groups (risk ratio 0.92, 95% confidence interval (CI) 0.49 to 1.73). In these two trials glycaemic control was not significantly different between the very tight and tight-moderate groups by the third trimester, although one trial of 22 women found significantly less maternal hypoglycaemia in the tight-moderate group.In a trial of 60 women and babies comparing tight (≤ 5.6 mmol/L FBG); moderate (5.6 to 6.7); and loose (6.7 to 8.9) glycaemic control targets, there were two neonatal deaths in the loose and none in the tight or moderate groups. There were significantly fewer women with pre-eclampsia, fewer caesareans and fewer birthweights greater than 90th centile in the combined tight-moderate compared with the loose group.

AUTHORS' CONCLUSIONS

In a very limited body of evidence, few differences in outcomes were seen between very tight and tight-moderate glycaemic control targets in pregnant women with pre-existing type 1 diabetes, including actual glycaemic control achieved. There is evidence of harm (increased pre-eclampsia, caesareans and birthweights greater than 90th centile) for 'loose' control (FBG above 7 mmol/L). Future trials comparing interventions, rather than glycaemic control targets, may be more feasible particularly for pregnant women with type 2 diabetes.

Circulating CD56+ cells of diabetic women show deviated homing potential for specific tissues during and following pregnancy

BACKGROUND

Human uterine natural killer (uNK) cells, the dominant lymphocytes in early pregnancy decidua, are important for spiral arterial remodelling. uNK cells are thought to arise from circulating CD56(bright) NK cells that egress into decidualizing endometrium. Both incomplete spiral arterial modification and aberrant NK cell function have been linked with pre-eclampsia, a syndrome that is more prevalent in diabetic women. Since previous in vitro studies have shown that changes in decidual endothelium induced by type 1 diabetes (T1D) reduce its interactions with circulating leucocytes, we hypothesized that diabetes additionally has direct effects on circulating CD56(+) NK cells that impair their decidual homing potential.

METHODS

Serial blood samples were collected from control, T1D and T2D pregnant women throughout and after pregnancy. In vitro adhesion under shear forces was used to assay the functional capacity of circulating leucocytes and of CD56(+) cells to adhere to endothelium in cryostat sections of gestation day (gd) 7 normal mouse decidua, pancreas and lymph node.

RESULTS

Fewer CD56(+) cells from diabetic compared with control women adhered to normal decidual endothelium. The CD56(+) cell/total cell adhesion ratio was also lower in diabetics. More diabetic CD56(+) cells adhered to pancreatic endothelium and their proportion was greater than for controls. Neither absolute nor proportional adhesion of CD56(+) cells to lymph node endothelium differed between diabetics and controls.

CONCLUSIONS

The CD56(+) cell adhesion patterns of T1D and T2D women differ from those of non-diabetic women and support the hypothesis that diabetes impairs mechanisms that could be used by CD56(+) cells for egress into decidua.