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WASHINGTON – Metformin’s role in preventing or delaying the onset of type 2 diabetes in women with a history of gestational diabetes mellitus has been firmly established by the Diabetes Prevention Program (DPP) trial – most recently, by 15-year follow-up data reported this year – and the drug should be front and center for clinicians who hope to stave off the “remarkable” incidence of type 2 diabetes after GDM, Robert E. Ratner, MD, maintained at the biennial meeting of the Diabetes in Pregnancy Study Group of North America.
The DPP included “the single largest population of women with a history of GDM that’s been looked at in a randomized controlled trial,” and considering its multiethnic population, the trial offers a reliable representative sample to ponder today when evaluating long-term use of metformin after GDM, said Dr. Ratner, a principal investigator of the National Institutes of Health–sponsored DPP and the DPP Outcomes Study and a former chief scientific & medical officer for the American Diabetes Association.
The drug stacked up equally to lifestyle interventions among DPP participants who had a history of GDM, but it’s important to appreciate that these interventions were intensive and that metformin is inexpensive, well tolerated, and “has a long safety record,” he said.
Results of follow-up out to 15 years
Of the more than 3,000 men and women enrolled in the landmark DPP, conducted during 1996-2001, 350 were women with a documented history of GDM and over 1,400 were women who had deliveries but no history of GDM. All participants had impaired glucose tolerance – defined for the trial as having both a fasting plasma glucose value of 95-125 mg/dL and a 2-hour value of 140-199 mg/dL after a 75-g glucose load – and were randomized to placebo, metformin, or intensive lifestyle intervention.
Metformin therapy reduced the incidence of diabetes by approximately 50% in women with a history of GDM, compared with the placebo group – as did lifestyle – over 3 years. The number needed to treat to prevent one case of diabetes was five. Women without a history of GDM, on the other hand, saw only a 14% reduction with metformin when compared with placebo (and a 49% reduction with lifestyle).
“In women with a history of GDM ... one pill twice a day for $4 a month worked as well as intensive lifestyle [change],” Dr. Ratner said, referring to the initial GDM-specific analysis of DPP data published in 2008 (J Clin Endocrinol Metab. 2008;93[12]:4774-9).
In a 10-year postrandomization follow-up, published in 2015, both metformin and lifestyle continued to be equally effective for the GDM group, reducing the progression to diabetes by 40% and 35%, respectively (J Clin Endocrinol Metab. 2015;100:1646-53). The number needed to treat to prevent one case of diabetes was seven. (Among women without a history of GDM, metformin did not reduce progression to diabetes.)
A recent DPP Outcomes Study analysis of metformin’s impact on diabetes prevention at 15 years, moreover, showed a 41% risk reduction among women with a history of GDM (Diabetes Care. 2019;42[4]:601-8).
Advice on prescribing metformin prophylactically
Asked after his presentation whether women with a history of GDM and either an elevated fasting plasma glucose value or an elevated 2-hour oral glucose tolerance test (GTT) value – or neither of the two – would benefit from taking metformin, Dr. Ratner said that “we’re stuck with inclusion criteria of the DPP, in which they had to meet both criteria ... What I’d say, though, is that not everyone with a history of GDM needs to be on metformin prophylactically. But [for women who have] prediabetes as defined by the ADA, the cost-benefit analysis points toward metformin.”
And with respect to early initiation and long-term use of the drug, “I would have absolutely no qualms about medicating a 25-year-old who had developed GDM and who in the postpartum period has prediabetes,” Dr. Ratner said during an open discussion. “She’s actually at the highest risk for developing type 2 very early.”
Kim Boggess, MD, who also presented on long-term use of metformin after GDM, said in the discussion period that she is often quick to recommend metformin therapy to her patients who have an elevated fasting plasma glucose value in the postpartum period, even when a 75-g oral GTT has not yet been performed. (The ADA and the American College of Obstetricians and Gynecologists recommend completion of an oral GTT at 4-12 weeks postpartum after GDM.)
“I start them [on metformin] especially if they’ve had a cesarean section. Even 2, 3, 4 weeks of profound hyperglycemia could have potentially deleterious effects,” said Dr. Boggess, professor and maternal-fetal medicine program director at the University of North Carolina, Chapel Hill. “If someone comes in [shortly after] and looks like they have pristine control, then it might be worth stopping the metformin for 3-5 days (and retesting).”
Dr. Ratner said that, in this clinical scenario, he would first ensure that the fasting glucose value “is a true fasting glucose” and “if it’s substantially elevated – I’m talking 100, 105, 110 mg/dL – I’d start metformin, and I’m not even sure I’d do the GTT.” But, he advised, “if you’re going to do the GTT, I’d stop the metformin the day before.”
In her presentation, Dr. Boggess pointed out that metformin wasn’t shown to be superior to lifestyle interventions in the DPP for preventing progression to type 2 DM, and that some women are more motivated for intensive lifestyle change than others. The ADA recommends, in fact, that either metformin or lifestyle interventions be prescribed to women with a history of GDM who are found to have prediabetes.
There are no data to support the use of metformin either during or after pregnancy to improve weight loss or reduce weight retention following pregnancy, but at least several studies have shown that lifestyle interventions are effective, she noted.
What is needed, Dr. Boggess said, are more data on the effects of metformin on cardiovascular disease risk, as well as larger studies of metformin in the postpartum period “to help us determine the best dose.” Some research on metformin use in the postpartum period has reported gastrointestinal side effects and dissatisfaction, she noted.
Dr. Ratner said that metformin’s main drawback is the need for occasional testing of B12 levels. Regarding weight loss and what was observed in the DPP, he said, women with a history of GDM who were randomized to intensive lifestyle interventions did not lose as much weight as women without a history of GDM.
Women who entered the DPP with a GDM history, he noted in his presentation, were essentially a “cohort of survivors.” They had an average age of 43 (compared with 52 years in the parous women without GDM) and a mean interval from the index GDM pregnancy of 11 years, which means that women with the highest risk of diabetes conversion were excluded, Dr. Ratner said.
Age was the only significantly different baseline characteristic between parous women with and without GDM, he noted. Women with a history of GDM who were randomized to placebo had a 71% higher incidence of diabetes than women without such a history – a striking natural history, Dr. Ratner said.
He and Dr. Boggess each reported that they have no financial or other interests that pose a conflict of interest.
WASHINGTON – Metformin’s role in preventing or delaying the onset of type 2 diabetes in women with a history of gestational diabetes mellitus has been firmly established by the Diabetes Prevention Program (DPP) trial – most recently, by 15-year follow-up data reported this year – and the drug should be front and center for clinicians who hope to stave off the “remarkable” incidence of type 2 diabetes after GDM, Robert E. Ratner, MD, maintained at the biennial meeting of the Diabetes in Pregnancy Study Group of North America.
The DPP included “the single largest population of women with a history of GDM that’s been looked at in a randomized controlled trial,” and considering its multiethnic population, the trial offers a reliable representative sample to ponder today when evaluating long-term use of metformin after GDM, said Dr. Ratner, a principal investigator of the National Institutes of Health–sponsored DPP and the DPP Outcomes Study and a former chief scientific & medical officer for the American Diabetes Association.
The drug stacked up equally to lifestyle interventions among DPP participants who had a history of GDM, but it’s important to appreciate that these interventions were intensive and that metformin is inexpensive, well tolerated, and “has a long safety record,” he said.
Results of follow-up out to 15 years
Of the more than 3,000 men and women enrolled in the landmark DPP, conducted during 1996-2001, 350 were women with a documented history of GDM and over 1,400 were women who had deliveries but no history of GDM. All participants had impaired glucose tolerance – defined for the trial as having both a fasting plasma glucose value of 95-125 mg/dL and a 2-hour value of 140-199 mg/dL after a 75-g glucose load – and were randomized to placebo, metformin, or intensive lifestyle intervention.
Metformin therapy reduced the incidence of diabetes by approximately 50% in women with a history of GDM, compared with the placebo group – as did lifestyle – over 3 years. The number needed to treat to prevent one case of diabetes was five. Women without a history of GDM, on the other hand, saw only a 14% reduction with metformin when compared with placebo (and a 49% reduction with lifestyle).
“In women with a history of GDM ... one pill twice a day for $4 a month worked as well as intensive lifestyle [change],” Dr. Ratner said, referring to the initial GDM-specific analysis of DPP data published in 2008 (J Clin Endocrinol Metab. 2008;93[12]:4774-9).
In a 10-year postrandomization follow-up, published in 2015, both metformin and lifestyle continued to be equally effective for the GDM group, reducing the progression to diabetes by 40% and 35%, respectively (J Clin Endocrinol Metab. 2015;100:1646-53). The number needed to treat to prevent one case of diabetes was seven. (Among women without a history of GDM, metformin did not reduce progression to diabetes.)
A recent DPP Outcomes Study analysis of metformin’s impact on diabetes prevention at 15 years, moreover, showed a 41% risk reduction among women with a history of GDM (Diabetes Care. 2019;42[4]:601-8).
Advice on prescribing metformin prophylactically
Asked after his presentation whether women with a history of GDM and either an elevated fasting plasma glucose value or an elevated 2-hour oral glucose tolerance test (GTT) value – or neither of the two – would benefit from taking metformin, Dr. Ratner said that “we’re stuck with inclusion criteria of the DPP, in which they had to meet both criteria ... What I’d say, though, is that not everyone with a history of GDM needs to be on metformin prophylactically. But [for women who have] prediabetes as defined by the ADA, the cost-benefit analysis points toward metformin.”
And with respect to early initiation and long-term use of the drug, “I would have absolutely no qualms about medicating a 25-year-old who had developed GDM and who in the postpartum period has prediabetes,” Dr. Ratner said during an open discussion. “She’s actually at the highest risk for developing type 2 very early.”
Kim Boggess, MD, who also presented on long-term use of metformin after GDM, said in the discussion period that she is often quick to recommend metformin therapy to her patients who have an elevated fasting plasma glucose value in the postpartum period, even when a 75-g oral GTT has not yet been performed. (The ADA and the American College of Obstetricians and Gynecologists recommend completion of an oral GTT at 4-12 weeks postpartum after GDM.)
“I start them [on metformin] especially if they’ve had a cesarean section. Even 2, 3, 4 weeks of profound hyperglycemia could have potentially deleterious effects,” said Dr. Boggess, professor and maternal-fetal medicine program director at the University of North Carolina, Chapel Hill. “If someone comes in [shortly after] and looks like they have pristine control, then it might be worth stopping the metformin for 3-5 days (and retesting).”
Dr. Ratner said that, in this clinical scenario, he would first ensure that the fasting glucose value “is a true fasting glucose” and “if it’s substantially elevated – I’m talking 100, 105, 110 mg/dL – I’d start metformin, and I’m not even sure I’d do the GTT.” But, he advised, “if you’re going to do the GTT, I’d stop the metformin the day before.”
In her presentation, Dr. Boggess pointed out that metformin wasn’t shown to be superior to lifestyle interventions in the DPP for preventing progression to type 2 DM, and that some women are more motivated for intensive lifestyle change than others. The ADA recommends, in fact, that either metformin or lifestyle interventions be prescribed to women with a history of GDM who are found to have prediabetes.
There are no data to support the use of metformin either during or after pregnancy to improve weight loss or reduce weight retention following pregnancy, but at least several studies have shown that lifestyle interventions are effective, she noted.
What is needed, Dr. Boggess said, are more data on the effects of metformin on cardiovascular disease risk, as well as larger studies of metformin in the postpartum period “to help us determine the best dose.” Some research on metformin use in the postpartum period has reported gastrointestinal side effects and dissatisfaction, she noted.
Dr. Ratner said that metformin’s main drawback is the need for occasional testing of B12 levels. Regarding weight loss and what was observed in the DPP, he said, women with a history of GDM who were randomized to intensive lifestyle interventions did not lose as much weight as women without a history of GDM.
Women who entered the DPP with a GDM history, he noted in his presentation, were essentially a “cohort of survivors.” They had an average age of 43 (compared with 52 years in the parous women without GDM) and a mean interval from the index GDM pregnancy of 11 years, which means that women with the highest risk of diabetes conversion were excluded, Dr. Ratner said.
Age was the only significantly different baseline characteristic between parous women with and without GDM, he noted. Women with a history of GDM who were randomized to placebo had a 71% higher incidence of diabetes than women without such a history – a striking natural history, Dr. Ratner said.
He and Dr. Boggess each reported that they have no financial or other interests that pose a conflict of interest.
WASHINGTON – Metformin’s role in preventing or delaying the onset of type 2 diabetes in women with a history of gestational diabetes mellitus has been firmly established by the Diabetes Prevention Program (DPP) trial – most recently, by 15-year follow-up data reported this year – and the drug should be front and center for clinicians who hope to stave off the “remarkable” incidence of type 2 diabetes after GDM, Robert E. Ratner, MD, maintained at the biennial meeting of the Diabetes in Pregnancy Study Group of North America.
The DPP included “the single largest population of women with a history of GDM that’s been looked at in a randomized controlled trial,” and considering its multiethnic population, the trial offers a reliable representative sample to ponder today when evaluating long-term use of metformin after GDM, said Dr. Ratner, a principal investigator of the National Institutes of Health–sponsored DPP and the DPP Outcomes Study and a former chief scientific & medical officer for the American Diabetes Association.
The drug stacked up equally to lifestyle interventions among DPP participants who had a history of GDM, but it’s important to appreciate that these interventions were intensive and that metformin is inexpensive, well tolerated, and “has a long safety record,” he said.
Results of follow-up out to 15 years
Of the more than 3,000 men and women enrolled in the landmark DPP, conducted during 1996-2001, 350 were women with a documented history of GDM and over 1,400 were women who had deliveries but no history of GDM. All participants had impaired glucose tolerance – defined for the trial as having both a fasting plasma glucose value of 95-125 mg/dL and a 2-hour value of 140-199 mg/dL after a 75-g glucose load – and were randomized to placebo, metformin, or intensive lifestyle intervention.
Metformin therapy reduced the incidence of diabetes by approximately 50% in women with a history of GDM, compared with the placebo group – as did lifestyle – over 3 years. The number needed to treat to prevent one case of diabetes was five. Women without a history of GDM, on the other hand, saw only a 14% reduction with metformin when compared with placebo (and a 49% reduction with lifestyle).
“In women with a history of GDM ... one pill twice a day for $4 a month worked as well as intensive lifestyle [change],” Dr. Ratner said, referring to the initial GDM-specific analysis of DPP data published in 2008 (J Clin Endocrinol Metab. 2008;93[12]:4774-9).
In a 10-year postrandomization follow-up, published in 2015, both metformin and lifestyle continued to be equally effective for the GDM group, reducing the progression to diabetes by 40% and 35%, respectively (J Clin Endocrinol Metab. 2015;100:1646-53). The number needed to treat to prevent one case of diabetes was seven. (Among women without a history of GDM, metformin did not reduce progression to diabetes.)
A recent DPP Outcomes Study analysis of metformin’s impact on diabetes prevention at 15 years, moreover, showed a 41% risk reduction among women with a history of GDM (Diabetes Care. 2019;42[4]:601-8).
Advice on prescribing metformin prophylactically
Asked after his presentation whether women with a history of GDM and either an elevated fasting plasma glucose value or an elevated 2-hour oral glucose tolerance test (GTT) value – or neither of the two – would benefit from taking metformin, Dr. Ratner said that “we’re stuck with inclusion criteria of the DPP, in which they had to meet both criteria ... What I’d say, though, is that not everyone with a history of GDM needs to be on metformin prophylactically. But [for women who have] prediabetes as defined by the ADA, the cost-benefit analysis points toward metformin.”
And with respect to early initiation and long-term use of the drug, “I would have absolutely no qualms about medicating a 25-year-old who had developed GDM and who in the postpartum period has prediabetes,” Dr. Ratner said during an open discussion. “She’s actually at the highest risk for developing type 2 very early.”
Kim Boggess, MD, who also presented on long-term use of metformin after GDM, said in the discussion period that she is often quick to recommend metformin therapy to her patients who have an elevated fasting plasma glucose value in the postpartum period, even when a 75-g oral GTT has not yet been performed. (The ADA and the American College of Obstetricians and Gynecologists recommend completion of an oral GTT at 4-12 weeks postpartum after GDM.)
“I start them [on metformin] especially if they’ve had a cesarean section. Even 2, 3, 4 weeks of profound hyperglycemia could have potentially deleterious effects,” said Dr. Boggess, professor and maternal-fetal medicine program director at the University of North Carolina, Chapel Hill. “If someone comes in [shortly after] and looks like they have pristine control, then it might be worth stopping the metformin for 3-5 days (and retesting).”
Dr. Ratner said that, in this clinical scenario, he would first ensure that the fasting glucose value “is a true fasting glucose” and “if it’s substantially elevated – I’m talking 100, 105, 110 mg/dL – I’d start metformin, and I’m not even sure I’d do the GTT.” But, he advised, “if you’re going to do the GTT, I’d stop the metformin the day before.”
In her presentation, Dr. Boggess pointed out that metformin wasn’t shown to be superior to lifestyle interventions in the DPP for preventing progression to type 2 DM, and that some women are more motivated for intensive lifestyle change than others. The ADA recommends, in fact, that either metformin or lifestyle interventions be prescribed to women with a history of GDM who are found to have prediabetes.
There are no data to support the use of metformin either during or after pregnancy to improve weight loss or reduce weight retention following pregnancy, but at least several studies have shown that lifestyle interventions are effective, she noted.
What is needed, Dr. Boggess said, are more data on the effects of metformin on cardiovascular disease risk, as well as larger studies of metformin in the postpartum period “to help us determine the best dose.” Some research on metformin use in the postpartum period has reported gastrointestinal side effects and dissatisfaction, she noted.
Dr. Ratner said that metformin’s main drawback is the need for occasional testing of B12 levels. Regarding weight loss and what was observed in the DPP, he said, women with a history of GDM who were randomized to intensive lifestyle interventions did not lose as much weight as women without a history of GDM.
Women who entered the DPP with a GDM history, he noted in his presentation, were essentially a “cohort of survivors.” They had an average age of 43 (compared with 52 years in the parous women without GDM) and a mean interval from the index GDM pregnancy of 11 years, which means that women with the highest risk of diabetes conversion were excluded, Dr. Ratner said.
Age was the only significantly different baseline characteristic between parous women with and without GDM, he noted. Women with a history of GDM who were randomized to placebo had a 71% higher incidence of diabetes than women without such a history – a striking natural history, Dr. Ratner said.
He and Dr. Boggess each reported that they have no financial or other interests that pose a conflict of interest.
REPORTING FROM THE DPSG-NA 2019