Gestational diabetes an independent risk factor for heart disease

Women with a history of gestational diabetes are at increased risk of cardiovascular disease – even if they maintain years of healthy glucose levels afterwards.
 
Such are the findings of new research published in Circulation.
 
It found that women with a previous history of gestational diabetes have a twofold higher risk of coronary artery calcification compared to women without previous gestational diabetes who had normal blood sugar levels.
 
That was the case regardless of whether the women with gestational diabetes maintained normal blood sugar levels, developed pre-diabetes, or were diagnosed with type 2 diabetes many years after pregnancy.
 
It is already well known that gestational diabetes predisposes a patient to type 2 diabetes, an established risk factor for cardiovascular disease.
 
However, Women’s Heart Clinic cardiologist and heart failure specialist Dr Monique Watts told newsGP this research brings to light a different issue for women with gestational diabetes.
 
‘What’s important here is that it’s not just about avoiding diabetes down the track – a woman [who had gestational diabetes] remains at risk of cardiovascular disease whether or not she develops type 2 diabetes,’ she said.
 
Dr Alex Polyakov, a senior lecturer in the Department of Obstetrics and Gynaecology at the University of Melbourne and a consultant obstetrician, gynaecologist and fertility specialist at the Reproductive Biology Unit at the Royal Women’s Hospital in Melbourne, told newsGP this research may alter the way gestational diabetes is followed up.
 
‘We know that type 2 diabetes is a major risk factor for heart disease and it was assumed in the past that this increased risk [of heart disease in patients who had gestational diabetes] related to abnormal glucose control later in life and the risk of developing type 2 diabetes,’ he said.
 
‘Now, this particular study demonstrates – not conclusively, but there is a suggestion – that even women who don’t develop glucose intolerance or type 2 diabetes later in life are also at increased risk.’
 
Consequently, Dr Polyakov says, the authors suggest having gestational diabetes alone is an ‘independent risk factor’ for developing cardiovascular disease.
 
‘So it doesn’t matter if you develop type 2 diabetes and glucose intolerance or not – you’re still at somewhat increased risk of heart disease later in life [just from having gestational diabetes],’ he said.
 
‘That is a novel finding.’
 
Dr Watts says the diagnosis of gestational diabetes alone warrants further cardiac follow-up.
 
‘Ideally a woman with gestational diabetes would be referred to somewhere like a women’s heart clinic, where we’ve got specialists and allied health that can educate the woman about the fact that this is not just about developing diabetes, but this is about your risk of developing heart disease,’ she said.
 
‘It’s about looking at other risk factors and figuring out how intensely we need to manage that risk but certainly starting early with diet, exercise, blood pressure monitoring and checking lipids.
 
‘So we can intervene early and look at things like lifestyle modifications and other risk factor modifications and follow this group more carefully and work harder with primary [care for] prevention.’
 
Dr Watts says ensuring women have such follow-up early on can make ‘a huge difference’ to health outcomes.

Dr Monique Watts says all patients with gestational diabetes require cardiac follow up.
 
Senior research scientist and lead author Dr Erica Gunderson offers a similar take home message.
 
‘Risk assessment for heart disease should not wait until a woman has developed pre-diabetes or type 2 diabetes,’ Dr Gunderson said.
 
‘Diabetes and other health problems that develop during pregnancy serve as early harbingers of future chronic disease risk, particularly heart disease.
 
‘Healthcare systems need to integrate the individual’s history of gestational diabetes into health records and monitor risk factors for heart disease, as well as the recommended testing for type 2 diabetes in these women at regular intervals, which is critical to target prevention efforts.’
 
Dr Watts says the way in which gestational diabetes increases cardiovascular disease risk is not yet understood and that it may relate to abnormal endothelial function or a low-grade inflammatory state that ‘starts up’ with gestational diabetes.
 
‘Whatever the mechanism, we know that it’s a marker [for cardiovascular disease]; that this is a woman that needs to be followed and we can improve outcomes with earlier interventions,’ she said.
 
Dr Watts hopes health professionals will take this information into consideration when assessing cardiac risk factors.
 
’It’s important that cardiologists become educated about the fact that this is a risk factor to ask about when a woman presents with symptoms,’ she said.
 
‘You don’t just need to ask about the traditional risk factors such as smoking, family history and hypertension – we do need to ask about complications in pregnancy because they are real risk factors for women.’
 
Dr Polyakov cautions this study is only preliminary, and that it does not look directly at the risk of heart disease per se, but at the development of calcification in the coronary arteries as a ‘surrogate’ marker for disease.
 
However, he says the finding that gestational diabetes alone leads to calcium scores that put women at increased risk of coronary artery disease is noteworthy.
 
‘So when a history is taken by a GP or a specialist, or another health professional, gestational diabetes in pregnancy should raise a red flag in terms of further possible screening for heart disease irrespective of their other risk factors,’ he said.
 
‘It’s an additional risk factor.’
 
Dr Watts also hopes GPs will utilise this information to ensure women with a history of gestational diabetes access appropriate care and follow-up for their heart.
 
‘GPs are in a unique position to know this about a woman, to educate a woman, and to appropriately refer on at a time when outcomes can be changed,’ she said.
 
‘Because otherwise time passes by and then we don’t get access to them as specialists until they’re referred to us with symptoms and often then, we’ve missed an opportunity.
 
‘It’s really important that GPs know about this, and know that it is appropriate to refer on at this point in time for a discussion about risk and risk modification.’
 
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cardiovascular disease gestational diabetes heart disease