In This Issue of Diabetes Care

Findings from a randomized, double-blind study (p. 2723) suggest that among diabetic patients with renal impairment, a once-weekly injection of the GLP-1R agonist albiglutide resulted in better glycemic improvement and had a similar safety profile compared to daily oral administration of sitagliptin. The new study, which was conducted at 134 centers in 15 countries, has potentially far-reaching implications for the growing numbers of diabetic patients who develop renal insufficiency in the course of their disease. Of the 507 patients in the trial, 254 were randomized to the albiglutide arm and the remaining 253 were in the sitagliptin arm. Patients’ mean age at baseline was 63.3 years, their BMI was 30.4 kg/m², HbA_1c was 8.2%, and participants had diabetes for an average of about 11 years when the study began. Almost all patients received at least one dose of study medication, and dropout was 20% and 25% in the albiglutide and sitagliptin groups, respectively. The trial’s primary end point was change in HbA_1c from baseline to week 26, with a secondary focus on fasting glucose, weight change, and achievement of treatment targets. A variety of safety end points were also examined. Reduction in HbA_1c was significantly greater in the albiglutide group than in the sitagliptin group (–0.83% vs. –0.52%), and decreases in both HbA_1c and fasting glucose were maintained through week 52. Although gastrointestinal adverse events were somewhat more common in the albiglutide group (31.7% vs. 25.2%), most events were mild or moderate. Notably, the albiglutide group showed a slight weight loss (–0.82 kg) during the study period, while the sitagliptin group showed a slight gain (+0.32 kg). The results of this trial suggest that albiglutide may be a viable option for diabetic patients across a wide range of renal impairment—a finding that may offer clinicians an appealing tool for treating this particularly challenging patient population. — Helaine E. Resnick, PhD, MPH

Leiter et al. Efficacy and safety of the once-weekly GLP-1 receptor agonist albiglutide versus sitagliptin in patients with type 2 diabetes and renal impairment: a randomized phase III study. Diabetes Care 2014;37:2723–2730

Compelling data in this issue of Diabetes Care (p. 2731) support the long-held belief that regular HbA_1c testing is associated with favorable glycemic control. Although the American Diabetes Association (ADA) and other organizations suggest that people with diabetes who are well controlled and on stable treatment should have their HbA_1c tested twice per year—with more frequent testing for patients whose glucose control is less favorable—data on the clinical impact of varied HbA_1c testing frequencies are limited. The new report capitalizes on a laboratory data set of more than 400,000 HbA_1c tests that were conducted on nearly 80,000 patients between 2008 and 2011 and shows a striking relationship between testing frequency and glycemic control that is highly consistent with published recommendations. People who were tested every 3 months had a 3.8% decrease in HbA_1c, while those who were tested only annually had a 1.5% increase. The data also revealed two critical frequency thresholds at 2 and 6 months; patients who were tested more frequently than 2 months showed no additional benefit in glycemic control, while those who were tested less frequently than 6 months showed marked declines in glycemic control. In the study sample as a whole, the data indicated that optimal HbA_1c testing frequency was every 4 months. The authors point out the largely untapped potential of existing laboratory data sets that can be used to address high-impact clinical questions related to control of key risk factors in diabetes and other chronic conditions. However, they also caution that their results must be interpreted in light of several limitations, including the inability to distinguish type 1 and type 2 diabetes, the absence of data on lifestyle and social factors that may influence testing frequency, and the inability to study the effects of treatments that may have influenced HbA_1c values. Nonetheless, the data not only support HbA_1c testing frequencies that are recommended by the ADA and other organizations but also provide insight into the potential morbidity and mortality that could be avoided with maximal compliance with HbA_1c testing recommendations. — Helaine E. Resnick, PhD, MPH

Driskell et al. Reduced testing frequency for glycated hemoglobin, HbA_1c, is associated with deteriorating diabetes control. Diabetes Care 2014;37:2731–2737

Although the unfavorable impact of fetal exposure to hyperglycemia among women with gestational diabetes mellitus (GDM) has been recognized for decades, a reliable marker for fetal glucose exposure has been elusive. A new study in this issue of Diabetes Care (p. 2830) reports intriguing data on a new method to measure glycation of hemoglobin α-chains (Glα) in fetal cord blood. The new method was evaluated in a case-control study of 37 neonates of women with GDM and 30 neonates of women with normal glucose tolerance. Glα was measured from cord blood samples that were collected within 15 min of delivery, and these measures were significantly higher among neonates of the GDM women compared with their normal counterparts. The Glα measures were also significantly correlated with maternal A_1c, but they were not correlated with birth weight, a measure that has been used for some time as a proxy for fetal glucose exposure. The authors point out that because the life span of fetal hemoglobin is 60–80 days, Glα may reflect glucose exposure during late pregnancy and therefore may be a promising new tool to identify newborns at high risk of future development of metabolic disease. Although this study was limited by the small sample size and the relatively narrow range of BMIs among the women who were studied, the results nonetheless point to the potential of Glα to enhance screening and risk stratification efforts among children of women with GDM. — Helaine E. Resnick, PhD, MPH

Dupont et al. Glycation of fetal hemoglobin reflects hyperglycemia exposure in utero. Diabetes Care 2014;37:2830–2833

A report in this issue of Diabetes Care (p. 2677) provides new insight on the relationship between maternal weight gain among women with type 1 diabetes and the birth weight of their offspring. Based on data from 115 women and their newborns, the new report shows that increasing gestational weight gain was associated with increased birth weight. These results are the first to highlight the association of weight gain and birth weight in a homogeneous cohort of women with type 1 diabetes, and they are consistent with an extensive literature supporting the unfavorable effect of excessive gestational weight gain that has previously focused on nondiabetic women and those with gestational diabetes mellitus. In 2009, the Institute of Medicine (IOM) responded to this compelling body of research by suggesting guidelines for maternal weight gain during pregnancy. These recommendations—categorized as insufficient, appropriate, and excessive—are defined according to women’s prepregnancy BMIs using widely accepted classifications (underweight, normal, overweight, and obese). Notably, the newly published results controlled for key confounders, including the IOM’s prepregnancy BMI categories. Even with adjustment for these and other factors such as glycemic control, smoking, and parity, women with type 1 diabetes who had higher weight gain during pregnancy delivered babies with higher birth weights. The new findings support the idea that greater attention should be paid to the care of women with type 1 diabetes, with a particular focus not only on glycemic control but also on ensuring appropriate weight gain during pregnancy. — Helaine E. Resnick, PhD, MPH

Secher et al. Higher gestational weight gain is associated with increasing offspring birth weight independent of maternal glycemic control in women with type 1 diabetes. Diabetes Care 2014;37:2677–2684