Endocrinologists clash over routine CGM during pregnancy

 

ORLANDO – Diabetes and pregnancy aren’t a good mix, but what about pregnancy and continuous glucose monitors (CGMs)? In a polite but pointed debate, two endocrinologists used each other’s studies as evidence to support their opposing perspectives about routine GCM use by diabetic women during pregnancy.

“This topic shouldn’t really be debated because the evidence is clear” in favor of CGM, said Denice S. Feig, MD, MSc, FRCPC, of the University of Toronto and Mt. Sinai Hospital, also in Toronto, in a presentation at the annual scientific sessions of the American Diabetes Association.

However, Elisabeth R. Mathiesen, MD, DMSc, of Rigshospitalet in Copenhagen, rebutted. She said her own research suggests CGM use may lead to larger babies and more premature births, convincing her to “say no to uncritical use of CGM in pregnancy.”

At issue: What is the best routine treatment for diabetic women before, during, and after pregnancy? As the American Diabetes Association noted in its 2018 Standards of Medical Care in Diabetes report, “specific risks of uncontrolled diabetes in pregnancy include spontaneous abortion, fetal anomalies, preeclampsia, fetal demise, macrosomia, neonatal hypoglycemia, and neonatal hyperbilirubinemia, among others. In addition, diabetes in pregnancy may increase the risk of obesity and type 2 diabetes [mellitus] in offspring later in life.”

In her presentation, Dr. Feig pointed to a 2017 study she led that examined the effectiveness of continuous, real-time CGM on women with type 1 diabetes mellitus who were pregnant or planning to become pregnant (Lancet. 2017 Nov 25;390(10110):2347-2359).

“The study, in effect, was two parallel, randomized trials, one in those who planned pregnancy and one in those who were pregnant,” Dr. Feig said.

Participants, aged 18-40 years, from 31 hospitals in seven European and North American nations, had to have hemoglobin A_1c levels greater than or equal to 6.5% during pregnancy or greater than or equal to 7% while planning pregnancy to be included in the study.

“We had a run-in phase to make sure they were able and willing to wear the CGM. Then we had 215 women in the pregnancy arm and 110 in the prepregnancy group randomized to real-time continuous CGM or standard care,” Dr. Feig said. The study ran for 34 weeks in the pregnant patients and for 24 weeks or until conception in the other women.

According to Dr. Feig, 70% of pregnant participants used CGM devices for more than 75% of the time. Compared with the control group, HbA_1c levels in those who used CGM fell by 0.19% (P = .0207). The researchers also reported that women in the CGM group spent 100 more minutes a day within the glucose target range.

No differences in outcomes such as gestational age at delivery and rate of preterm delivery was found, although incidence of large-for-gestational-age infants, hypoglycemia requiring dextrose infusion, and neonatal ICU admission were lower in the CGM group to a statistically significant degree. “The numbers needed to treat were very small at six to eight women to reduce one of these events,” said Dr. Feig, who added that the numbers suggest the potential for cost savings.

 

Whatever the case, she said, “what price would you place on your baby avoiding a prolonged stay in the NICU? I think [it’s] priceless.”

She added that 80% of participants reported having trouble with the devices, which she attributed to the technology being old.

As for the planned pregnancy group, the study noted that “it did not have sufficient power to detect the magnitude of differences that were significant in the pregnancy trial.”

However, Dr. Feig said the study showed a trend toward lower HbA_1c levels among CGM users in this population in which “tight glycemic control is absolutely paramount,” and that other studies also provide evidence supporting CGM use through the breastfeeding period.

Dr. Feig also pointed to a similar 2013 study coauthored by Dr. Mathiesen, her debate opponent. Dr. Feig said its findings are weakened because participants used CGM intermittently. She also pointed to the low participation (64%) in CGM by women assigned to a CGM group. (Diabetes Care. 2013 Jul;36[7]:1877-83)

In that study, researchers assigned 123 Danish women with type 1 diabetes mellitus and 31 women with type 2 diabetes mellitus to use real-time CGM for 6 days at various points in pregnancy or to only engage in routine care (including self-monitored plasma glucose seven times daily).

Researchers found no difference in HbA_1c levels at 33 weeks between the groups, and they found similar rates of severe hypoglycemia and perinatal outcomes such as large-for-gestational-age infants.

For her part, Dr. Mathiesen told the ADA audience that the results were unexpected: The women in the CGM group were free to use the devices continuously but few did. And while she expected the CGM group to have fewer problems on the fetal outcome front, “we saw a tendency toward even bigger babies, more preterm deliveries.”

These results, Dr. Mathiesen said, make her skeptical of a blanket recommendation to use CGM in pregnancy. Women aren’t eager to upload their glucose readings, making it difficult for doctors to make adjustments. “My women are Vikings. They come from Denmark,” she said, but “even these women don’t upload their glucose data between visits. ... I rarely have women who upload their data and look at their curves themselves. I think that’s a major disadvantage.”

Dr. Mathiesen also pointed to Dr. Feig’s study and noted that many women used CGM less than 75% of the time. In addition, 80% reported problems with the technology. “I’ve seen lots of skin problems with sensors. One lady used CGM during pregnancy; 4 years later, during another pregnancy, she showed me the mark of her sensor.”

Finally, the cost of CGM use is high considering the ongoing expense of the devices and the nurse time needed to upload data in the clinic. “As a rough estimate, the cost of CGM use in about 20 women during their pregnancies is the cost of the salary for one nurse per year,” she said.

Dr. Feig reported speaking fees from Medtronic, which provided CGM devices at reduced cost to her trial. Dr. Mathiesen reported research funding from the Novo Nordisk Foundation and speaker fees from Novo Nordisk, Lilly, AstraZeneca, and Sanofi-Aventis.

 

ORLANDO – Diabetes and pregnancy aren’t a good mix, but what about pregnancy and continuous glucose monitors (CGMs)? In a polite but pointed debate, two endocrinologists used each other’s studies as evidence to support their opposing perspectives about routine GCM use by diabetic women during pregnancy.

“This topic shouldn’t really be debated because the evidence is clear” in favor of CGM, said Denice S. Feig, MD, MSc, FRCPC, of the University of Toronto and Mt. Sinai Hospital, also in Toronto, in a presentation at the annual scientific sessions of the American Diabetes Association.

However, Elisabeth R. Mathiesen, MD, DMSc, of Rigshospitalet in Copenhagen, rebutted. She said her own research suggests CGM use may lead to larger babies and more premature births, convincing her to “say no to uncritical use of CGM in pregnancy.”

At issue: What is the best routine treatment for diabetic women before, during, and after pregnancy? As the American Diabetes Association noted in its 2018 Standards of Medical Care in Diabetes report, “specific risks of uncontrolled diabetes in pregnancy include spontaneous abortion, fetal anomalies, preeclampsia, fetal demise, macrosomia, neonatal hypoglycemia, and neonatal hyperbilirubinemia, among others. In addition, diabetes in pregnancy may increase the risk of obesity and type 2 diabetes [mellitus] in offspring later in life.”

In her presentation, Dr. Feig pointed to a 2017 study she led that examined the effectiveness of continuous, real-time CGM on women with type 1 diabetes mellitus who were pregnant or planning to become pregnant (Lancet. 2017 Nov 25;390(10110):2347-2359).

“The study, in effect, was two parallel, randomized trials, one in those who planned pregnancy and one in those who were pregnant,” Dr. Feig said.

Participants, aged 18-40 years, from 31 hospitals in seven European and North American nations, had to have hemoglobin A_1c levels greater than or equal to 6.5% during pregnancy or greater than or equal to 7% while planning pregnancy to be included in the study.

“We had a run-in phase to make sure they were able and willing to wear the CGM. Then we had 215 women in the pregnancy arm and 110 in the prepregnancy group randomized to real-time continuous CGM or standard care,” Dr. Feig said. The study ran for 34 weeks in the pregnant patients and for 24 weeks or until conception in the other women.

According to Dr. Feig, 70% of pregnant participants used CGM devices for more than 75% of the time. Compared with the control group, HbA_1c levels in those who used CGM fell by 0.19% (P = .0207). The researchers also reported that women in the CGM group spent 100 more minutes a day within the glucose target range.

No differences in outcomes such as gestational age at delivery and rate of preterm delivery was found, although incidence of large-for-gestational-age infants, hypoglycemia requiring dextrose infusion, and neonatal ICU admission were lower in the CGM group to a statistically significant degree. “The numbers needed to treat were very small at six to eight women to reduce one of these events,” said Dr. Feig, who added that the numbers suggest the potential for cost savings.

 

Whatever the case, she said, “what price would you place on your baby avoiding a prolonged stay in the NICU? I think [it’s] priceless.”

She added that 80% of participants reported having trouble with the devices, which she attributed to the technology being old.

As for the planned pregnancy group, the study noted that “it did not have sufficient power to detect the magnitude of differences that were significant in the pregnancy trial.”

However, Dr. Feig said the study showed a trend toward lower HbA_1c levels among CGM users in this population in which “tight glycemic control is absolutely paramount,” and that other studies also provide evidence supporting CGM use through the breastfeeding period.

Dr. Feig also pointed to a similar 2013 study coauthored by Dr. Mathiesen, her debate opponent. Dr. Feig said its findings are weakened because participants used CGM intermittently. She also pointed to the low participation (64%) in CGM by women assigned to a CGM group. (Diabetes Care. 2013 Jul;36[7]:1877-83)

In that study, researchers assigned 123 Danish women with type 1 diabetes mellitus and 31 women with type 2 diabetes mellitus to use real-time CGM for 6 days at various points in pregnancy or to only engage in routine care (including self-monitored plasma glucose seven times daily).

Researchers found no difference in HbA_1c levels at 33 weeks between the groups, and they found similar rates of severe hypoglycemia and perinatal outcomes such as large-for-gestational-age infants.

For her part, Dr. Mathiesen told the ADA audience that the results were unexpected: The women in the CGM group were free to use the devices continuously but few did. And while she expected the CGM group to have fewer problems on the fetal outcome front, “we saw a tendency toward even bigger babies, more preterm deliveries.”

These results, Dr. Mathiesen said, make her skeptical of a blanket recommendation to use CGM in pregnancy. Women aren’t eager to upload their glucose readings, making it difficult for doctors to make adjustments. “My women are Vikings. They come from Denmark,” she said, but “even these women don’t upload their glucose data between visits. ... I rarely have women who upload their data and look at their curves themselves. I think that’s a major disadvantage.”

Dr. Mathiesen also pointed to Dr. Feig’s study and noted that many women used CGM less than 75% of the time. In addition, 80% reported problems with the technology. “I’ve seen lots of skin problems with sensors. One lady used CGM during pregnancy; 4 years later, during another pregnancy, she showed me the mark of her sensor.”

Finally, the cost of CGM use is high considering the ongoing expense of the devices and the nurse time needed to upload data in the clinic. “As a rough estimate, the cost of CGM use in about 20 women during their pregnancies is the cost of the salary for one nurse per year,” she said.

Dr. Feig reported speaking fees from Medtronic, which provided CGM devices at reduced cost to her trial. Dr. Mathiesen reported research funding from the Novo Nordisk Foundation and speaker fees from Novo Nordisk, Lilly, AstraZeneca, and Sanofi-Aventis.

 

ORLANDO – Diabetes and pregnancy aren’t a good mix, but what about pregnancy and continuous glucose monitors (CGMs)? In a polite but pointed debate, two endocrinologists used each other’s studies as evidence to support their opposing perspectives about routine GCM use by diabetic women during pregnancy.

“This topic shouldn’t really be debated because the evidence is clear” in favor of CGM, said Denice S. Feig, MD, MSc, FRCPC, of the University of Toronto and Mt. Sinai Hospital, also in Toronto, in a presentation at the annual scientific sessions of the American Diabetes Association.

However, Elisabeth R. Mathiesen, MD, DMSc, of Rigshospitalet in Copenhagen, rebutted. She said her own research suggests CGM use may lead to larger babies and more premature births, convincing her to “say no to uncritical use of CGM in pregnancy.”

At issue: What is the best routine treatment for diabetic women before, during, and after pregnancy? As the American Diabetes Association noted in its 2018 Standards of Medical Care in Diabetes report, “specific risks of uncontrolled diabetes in pregnancy include spontaneous abortion, fetal anomalies, preeclampsia, fetal demise, macrosomia, neonatal hypoglycemia, and neonatal hyperbilirubinemia, among others. In addition, diabetes in pregnancy may increase the risk of obesity and type 2 diabetes [mellitus] in offspring later in life.”

In her presentation, Dr. Feig pointed to a 2017 study she led that examined the effectiveness of continuous, real-time CGM on women with type 1 diabetes mellitus who were pregnant or planning to become pregnant (Lancet. 2017 Nov 25;390(10110):2347-2359).

“The study, in effect, was two parallel, randomized trials, one in those who planned pregnancy and one in those who were pregnant,” Dr. Feig said.

Participants, aged 18-40 years, from 31 hospitals in seven European and North American nations, had to have hemoglobin A_1c levels greater than or equal to 6.5% during pregnancy or greater than or equal to 7% while planning pregnancy to be included in the study.

“We had a run-in phase to make sure they were able and willing to wear the CGM. Then we had 215 women in the pregnancy arm and 110 in the prepregnancy group randomized to real-time continuous CGM or standard care,” Dr. Feig said. The study ran for 34 weeks in the pregnant patients and for 24 weeks or until conception in the other women.

According to Dr. Feig, 70% of pregnant participants used CGM devices for more than 75% of the time. Compared with the control group, HbA_1c levels in those who used CGM fell by 0.19% (P = .0207). The researchers also reported that women in the CGM group spent 100 more minutes a day within the glucose target range.

No differences in outcomes such as gestational age at delivery and rate of preterm delivery was found, although incidence of large-for-gestational-age infants, hypoglycemia requiring dextrose infusion, and neonatal ICU admission were lower in the CGM group to a statistically significant degree. “The numbers needed to treat were very small at six to eight women to reduce one of these events,” said Dr. Feig, who added that the numbers suggest the potential for cost savings.

 

Whatever the case, she said, “what price would you place on your baby avoiding a prolonged stay in the NICU? I think [it’s] priceless.”

She added that 80% of participants reported having trouble with the devices, which she attributed to the technology being old.

As for the planned pregnancy group, the study noted that “it did not have sufficient power to detect the magnitude of differences that were significant in the pregnancy trial.”

However, Dr. Feig said the study showed a trend toward lower HbA_1c levels among CGM users in this population in which “tight glycemic control is absolutely paramount,” and that other studies also provide evidence supporting CGM use through the breastfeeding period.

Dr. Feig also pointed to a similar 2013 study coauthored by Dr. Mathiesen, her debate opponent. Dr. Feig said its findings are weakened because participants used CGM intermittently. She also pointed to the low participation (64%) in CGM by women assigned to a CGM group. (Diabetes Care. 2013 Jul;36[7]:1877-83)

In that study, researchers assigned 123 Danish women with type 1 diabetes mellitus and 31 women with type 2 diabetes mellitus to use real-time CGM for 6 days at various points in pregnancy or to only engage in routine care (including self-monitored plasma glucose seven times daily).

Researchers found no difference in HbA_1c levels at 33 weeks between the groups, and they found similar rates of severe hypoglycemia and perinatal outcomes such as large-for-gestational-age infants.

For her part, Dr. Mathiesen told the ADA audience that the results were unexpected: The women in the CGM group were free to use the devices continuously but few did. And while she expected the CGM group to have fewer problems on the fetal outcome front, “we saw a tendency toward even bigger babies, more preterm deliveries.”

These results, Dr. Mathiesen said, make her skeptical of a blanket recommendation to use CGM in pregnancy. Women aren’t eager to upload their glucose readings, making it difficult for doctors to make adjustments. “My women are Vikings. They come from Denmark,” she said, but “even these women don’t upload their glucose data between visits. ... I rarely have women who upload their data and look at their curves themselves. I think that’s a major disadvantage.”

Dr. Mathiesen also pointed to Dr. Feig’s study and noted that many women used CGM less than 75% of the time. In addition, 80% reported problems with the technology. “I’ve seen lots of skin problems with sensors. One lady used CGM during pregnancy; 4 years later, during another pregnancy, she showed me the mark of her sensor.”

Finally, the cost of CGM use is high considering the ongoing expense of the devices and the nurse time needed to upload data in the clinic. “As a rough estimate, the cost of CGM use in about 20 women during their pregnancies is the cost of the salary for one nurse per year,” she said.

Dr. Feig reported speaking fees from Medtronic, which provided CGM devices at reduced cost to her trial. Dr. Mathiesen reported research funding from the Novo Nordisk Foundation and speaker fees from Novo Nordisk, Lilly, AstraZeneca, and Sanofi-Aventis.