Intensive blood sugar control doesn’t have lasting cardiovascular benefits for those with diabetes

Medha Munshi, MD

Contributor

In 2009, the New England Journal of Medicine published results from the Veterans Affairs Diabetes Trial (VADT). The study found that intensive glucose (blood sugar) control in older men with longstanding type 2 diabetes did not significantly reduce their risk of major cardiovascular (CV) events, including heart attack, stroke, and death from CV causes, compared with standard blood sugar control.

Researchers recently reported 15-year follow-up results from VADT. They found that intensive blood sugar control did not exert any “legacy effect”: the intensive blood sugar control group did not enjoy CV benefits 15 years after the start of the study.

The Veterans Affairs Diabetes Trial

The VADT study originally enrolled over 1,700 veterans with longstanding type 2 diabetes, who were at high risk of cardiovascular disease, and had poorly controlled blood sugar when they enrolled in the study. At the time of enrollment, study participants had been diagnosed with diabetes for an average of 12 years. Their average A1c level, a measure of average blood sugar levels over the previous two to three months, was 9.4%.

The participants were randomly assigned to either intensive glucose-lowering therapy or usual care for about 5.6 years. At the completion of the study, there was a significant difference in blood sugar control: the average A1c in the intensive treatment group was 6.9%, while the average A1c in the usual care group was 8.4%.

Despite the lower A1c levels, there were no benefits shown from intensive treatment on CV outcomes, which included nonfatal heart attack, nonfatal stroke, new or worsening congestive heart failure, amputation for diabetes-related tissue damage, or death from CV causes.

No long-term cardiovascular benefit of intensive blood sugar control

A follow-up observational study was then undertaken to assess whether intensive treatment during the 5.6-year study period had any long-lasting effects, after the interventions were completed. The 10-year VADT follow-up showed some benefits to intensive treatment with regard to CV events. At that time, participants in the intensive treatment group still had lower A1c levels compared to the usual care group, despite the gap of several years since the completion of the study.

However, at the newly published 15-year follow-up, the benefits of intensive control on any of the CV outcomes were lost. By this time, both groups had similar A1c levels of about 8%.

This phenomenon may suggest that to achieve the CV benefits, blood sugar control needs to be maintained and that the short-term tight control, without lasting blood sugar control, may not have long-lasting effects.

New evidence supports existing evidence

The new VADT results add to existing evidence from previous large studies that have failed to show any long-lasting benefits of intensive blood sugar control during observational follow-up. One study, however, did show some beneficial legacy effect. The United Kingdom Prospective Diabetes Study (UKPDS) evaluated intensive treatment versus usual care in adults with newly diagnosed type 2 diabetes. When the UKPDS cohort was evaluated 10 years after the completion of the study, the participants from the intensive treatment arm showed benefits with regard to cardiovascular disease, compared to standard care.

Taken together, the evidence suggests that older adults with longer duration of diabetes and/or multiple coexisting conditions may not benefit from intensive blood sugar control. On the other hand, intensive treatment might be beneficial in younger patients, with shorter duration of diabetes and fewer coexisting medical conditions.

Individualize treatment and control other cardiovascular risk factors

Personalization of goals and treatment regimens that can be maintained safely over the long term by the patient might be the best strategy to lower the risk of cardiovascular disease. As I discussed in a previous blog post, treatment of older adults should consider possible dangers of intensive treatment. For example, intensive blood sugar control can overshoot and lead to hypoglycemia, a potentially dangerous condition in which blood sugar falls too low. Hypoglycemic episodes in older adults are particularly harmful and may negate the possible benefits or tighter diabetes control. In older adults, rather than aiming for tight control, we aim for the best control that can be achieved without increasing the risk of hypoglycemia.

For reducing CV risk, the authors of an editorial that accompanied the NEJM study recommend prioritizing interventions that address other CV risk factors. That includes quitting smoking, and managing blood pressure and cholesterol levels with medication, if needed. Newer classes of diabetes medications, such as sodium glucose cotransporter-2 (SGLT2) inhibitors and glucagon-like peptide-1 (GLP-1) receptor agonists appear to have CV benefits and low risk of hypoglycemia, and may be considered as well.

Related Information: Living Well with Diabetes

Comments:

  1. Dr.M.Balachandran

    Tight control in older age more often is deleterious than a bit liberal control in ground reality.Needs explanation and scientific data to back up. Anyone to support the postulate?

  2. Mark Sebastian, PhD

    A lot of money spent to learn that self-control with regard to eating improves your health, and that reverting to uncontrolled eating habits kills the benefits all the efforts achieved.

  3. Murar Yeolekar

    Influence of dietary restriction / correction in an increasingly fragile physiology , and the effect of drugs in an altered Internal mileau related to organ (dys)function could be the reason why tighter targets may be not as beneficial. Further the elderly included in clinical trials may be minuscule for any meaningful conclusions to be drawn. Most important aspect of elderly Diabetes care is to prevent hypoglcemia . Prof ME Yeolekar , Mumbai.

  4. RUP GOSWAMI

    Very useful and educative.
    Me at 82 am a Diabetes II patient since last 10 years.
    My opening Glycemic Index was around 7.2 10 years ago.
    By extreme selected diet control ( I am a Vegetarian)
    and medicine Glycomet 250 mg, ( Metmorphin) I had brought it down HbA1c to 5.4 only.
    I stopped eating even a grain of sugar, sugar product, anything sweet , nil carb but limited protein diet having a total daily Calorie of 800/850 ( (Newcastle Diet)Dirt)reduced weight from 195 pounds to 165 pounds in 2 years .( without any excercise as My knees are damaged and am restricted to limited walking) My doctor, Dr. J. Srikant then advised me that due to my older age I should not bring down HbA1c to such low level but maintain it around 6/6.5, which I am following .
    I also had BP around 170/95 10 yrs ago and same doctor prescribed me medicine, a combination of Telmesartin
    and Amlodipine 40/5 mg(Trade name TAZLOC M) ( from the first day10 yrs ago till now) and till that time my BP remained normal at 130/80 for all these 10 years.
    All four right side RRRB in my heart are completely blocked but I did not have any heart complaint till today. I am also a patient of well enlarged Prostrate for which he prescribed Tamsulosin 0.4 mg- (Trade name
    URIMAX 0.4 mg) and a homeopathic medicine named
    SABAL SERULETA -Q Strength ( meaning Mother Tincture)- 10 drops ( without water) twice a day.
    The prostrate does not give me any trouble and have very smooth flow. It has not enlarged any further since last 10 years. I go to pee in night for once or max two times in night and have sound sleep ( hit the bed and fall asleep).

  5. Donald O Teunissen

    How are they controlling blood sugar levels, unless you do it by severe reduction of refined carbs and sugar, taking pharmaceuticals to force the blood sugar into cells that can’t use it is quite pointless. We need to address the root cause, not the symptoms.

  6. Dr Prashant

    This information is very informative

  7. Blaine T

    A1C of 6.9 is not tight control, they need to do the study they study said they were going to do and actual control the blood sugar and get it down under 6 or lower. I am type 1 and my A1C is 5 and has been for many years so it is possible so do the study and then see what happens.

  8. Jeff J.

    This article doesn’t say what the intensive management involves. If it involves giving insulin or sulfonylureas, of course there’s no benefit. These do nothing to reduce the body’s sugar load, and they increase insulin levels. SLGT2 drugs actually get sugar out of the body. As does intermittent fasting and low carb eating. I’m doing those three things and I’ve gotten off of four medications, while my a1c is almost normal. Not easy, but worth it.

  9. Geri Peterson

    Why isn’t there anything in this study about a healthy way of eating?

    (The American Diabetes association has recently published information about eating a healthy ketogenic diet to reverse type 2 diabetes. )

  10. Amy WP

    The title and the way this article is framed leads people with long standing diabetes away from good blood glucose control. Yes the results do not show a significant difference in CV risk at 15 years, but notably A1C values also did not differ. This points to a problem with maintaining good control.

  11. Tandi

    “Intensive control” with what ? Medications ? I’d love to see the difference of those under “ intensive control “ with diet alone as opposed to control with medications- medications are treating the symptom of high blood glucose – the underlying disease is still doing its damage , whereas lifestyle changes treat the actual disease 🤔

  12. resko1999

    What other factors were tracked? Was family history considered, genetic predisposition, lifestyle (exercise, eating habits/patterns, sleep hygiene, BP, inflammation markers, any drug usage, social status…) I did not read the entire study but this article nowhere does it mention all of those factors. Yes, I lowered my A1C but I kept eating processed foods and stayed till midnight watching TV and had delicious, sugar laden cereal, and had minimal daily movement…what the fack do you expect.

  13. Garrick

    How about a whole food plant based diet with very little oil intake. That walk about 2 mile’s every day and you too can out live all your doctors.

    Heal yourself and save the world, Vegan for the win!

  14. Shirla

    Half of us, including people without diabetes (who have low A1Cs) are going to die from cardiovascular disease. It is the food!!! Until we switch to a whole-food plant-based diet that is low in fat, cv disease will continue progress. Good blood sugar control on healthy foods should be the goal – and science is clearly pointing to healthy foods as whole-food (not processed, no oil) and plant-based (veggies, fruit, legumes, whole intact grains, nuts, seeds, spices and herbs). The science is clear. It is the food! (Other lifestyle changes, like moving your body, meditating, and sleeping well certainly help.) But good blood sugar control while eating meat, cheese, eggs and oil leads to chronic disease for all of us. Nutrition research is clear on this. Aim for fruit and vegetables with every meal. Beans, greens, and berries are us!!! Keep reducing meat, dairy, and egg. We can do this!!!!! Our bodies will thank us by feeling so much better.

  15. Joe Stone

    If you wish to eliminate cardiovascular risk and other metabolic ailments that are associated with T2D, eliminate carbohydrates from the diet.

  16. Abukar

    Keep it up, hope a solution will be found in future. I am also a type 2 diabetic patient.

  17. Fawzi mousa

    Nice and informative article

  18. Dr SOMASUNDRAM MANIKAM

    The BSControl over longterm helps to allay any complications that may arise and definitely helps in overall reduction in peripheral nerve damage.
    Thus, saving unwanted surgery n further loss of body parts to surgery.

    Just be conscious and take an array of vitamins along with the medication to protect the vital organs.

    Aim for more of low glycemic index foods along with an intake of at least > 20 grams of fiber.
    Such foods also help to maintain a healthy gut microbiota.

  19. Chandra Shan

    It is well known that duration of diabetes is the reason for complications.

    Older adults with 12 years of diabetes have already developed atherosclerotic plaques which dislodges and give heart attacks and strokes. Intensive control of sugar is not going to dissolve the plaques at this stage.

    As vessel ages these patches are going to dislodge one day.

    Older diabetes with plaques would benefit of cyclodextrin which regress the plaques, inaddition to intense sugar. control.

  20. AF Kay

    The therapeutic approach to managing diabetes is to lower the patient’s blood glucose level. Not much attention is being paid to hyperinsulinemia. Isn’t hyperinsulinemia just as bad as, if not worse than, hyperglycemia when it comes to long-term adverse health consequences?

  21. Pauline Burney

    Please where is the definition of intensive blood sugar control?
    Are we talking hypoglycaemics and insulin,
    Or are we talking intensive dietary change?
    Were both assessed?
    Type 2 diabetics could read this and interpret “what the heck, I might as well just give up”
    Will read the report, but many people just read the headlines, and these could be misinterpreted I think

  22. RivkaC

    I’m a female, age 62, very slightly overweight, active, diagnosed 7 years ago and my A1c is 5.6. I intend to continue to practice tight blood glucose control and live a quality life ’til at least 90!

  23. Daniel Manu

    It is a shame that Harvard Medical School should even be talking about pharmaceuticals for type 2 diabetes. Have they heard of the work of Dr. T. Colin Campbell. I followed his Whole Food Plant-Based low fat no animal protein diet and reversed diabetes type 2 in just two weeks. Whereas the President of AHA had his heart attack at 52, Dr. Campbell in his 80s is no only CVD free but is an epitome of health and even said in one of his lectures that he does not use any medicine. Harvard Medical School please promote his protocol and not pharmaceuticals and teach the new generation of Doctors of the superiority of Lifestyle Medicine over allopathic medicine. Thanks.

  24. Keith Meck

    Your always doing testing, studies and TV commercials on T2 when the hell are you going to advocate T1, the diabetes community is truly asinine in regards to real diabetes care.

  25. azure

    ” Newer classes of diabetes medications, such as sodium glucose cotransporter-2 (SGLT2) inhibitors and glucagon-like peptide-1 (GLP-1) receptor agonists appear to have CV benefits and low risk of hypoglycemia, and may be considered as well.” Helpful that new medications are being developed but what’s the price tag? how many people in the US will be able to afford either if either or both would be helpful for their DM?

    • Ian Lake

      Do you think that, Obesity, NAFLD, Pre Diabetes, Type 2 Diabetes, all have the same cause? I do. So simply drilling down the glucose for its own sake will have little effect on CVD. Because it is not the glucose that is the problem. Did your study measure insulin levels? Did your study look at sub populations who might have done better and analysed their diet? It could be that the make up of the diet was driving the disease process in those people vulnerable. And finally, did any of your study participants go into remission?

    • Reality

      Ask the PBMs who abscound 50% of the list price of the drug and rarely pass that on to the patient.

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