After a heart attack, abnormal glucose tolerance common and a risk

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In this new study done in Japan, 275 people admitted with a heart attack were evaluated for diabetes and pre-diabetes.  They were evaluated 14 days after the heart attack, and people who had significant complications in hospital were excluded.

Strikingly, of the 275 consecutive patients with AMI (acute heart attack) they evaluated, only 78 had normal glucose tolerance (only 28%).

There were 85 who were classed in the “diabetes” group, either because they had already been diagnosed before their heart attack or because they had persistent fasting blood sugar in the diabetic range (above 125 mg/dl).  The other 112 showed abnormal glucose tolerance when they were tested just prior to discharge from the hospital, either in the diabetic or pre-diabetic range. Thus, the “AGT” group included people who did NOT meet diagnostic criteria for diabetes based on fasting glucose levels, but did meet criteria for either pre-diabetes or diabetes due to the degree of rise in their blood glucose after drinking 75 grams of glucose. (at least 140 mg/dl at 2 hours)

For the AGT group:

  • they had a worse outcome on follow-up than the people without abnormal glucose tolerance.  In fact, their outcome was just as bad as for the people classed in the “diabetes” group (“an equivalent prognosis to the DM group“)

Refered to as a “Hazard Ratio” (HR), they were looking at the risk for “a major cardiovascular event” (you don’t want one of those).  Those people with abnormal glucose tolerance had 2.65 times as much Hazard Ratio as those with normal glucose tolerance, which was not statistically different from the people with diabetes, who had 3.27 times as much HR as those with normal glucose tolerance. (Impaired glucose tolerance is about glucose rising after meals.)

  • Having an elevated fasting blood glucose (under 126 mg/dl) was not found to be associated with a worse outcome during the follow-up period (however, the result found suggest that a study with a larger number of subjects might show something different).

The study was not large. If a study with more people were done, it might show a bit more gradation between the outcomes for the different groups.

Take Home Message: Again, know how high your blood glucose rises after meals

LINK to the full text of the research study

Heart. 2012 Jun;98(11):848-54.

Newly diagnosed glucose intolerance and prognosis after acute myocardial infarction: comparison of post-challenge versus fasting glucose concentrations.

Tamita K, Katayama M, Takagi T, Yamamuro A, Kaji S, Yoshikawa J, Furukawa Y.

Source

Department of Cardiovascular Medicine, Nishinomiya Watanabe Cardiovascular Center, 3-25 Ikeda-cho, Nishinomiya City 662-0911, Japan;  k-tamita@yc4.so-net.ne.jp.

Abstract

BACKGROUND:

Recent studies have demonstrated that newly diagnosed glucose intolerance is common among patients with acute myocardial infarction (AMI). The purpose of this study was to assess the long-term clinical cardiovascular outcomes in participants with AMI with abnormal fasting glucose compared with normal fasting glucose and an abnormal oral glucose tolerance test (OGTT) compared with a normal OGTT.

METHODS:

A prospective study was performed in 275 consecutive patients with AMI, 85 of whom had pre-diagnosed diabetes mellitus (DM). Those without DM were divided into two groups based on the 75 g OGTT at the time of discharge. Abnormal glucose tolerance (AGT) was defined as 2 h glucose ≥140 mg/dl; 78 patients had normal glucose tolerance (NGT) and 112 had AGT. The same patients were also reclassified into the normal fasting glucose group (NFG; n=168) or the impaired fasting glucose group (IFG; n=22). The association between the glucometabolic status and long-term major adverse cardiovascular event rates was evaluated.

RESULTS:

Kaplan-Meier survival curves showed that the AGT group had a worse prognosis than the NGT group and an equivalent prognosis to the DM group (p<0.0005). Cox proportional hazard model analysis showed that the HR of AGT to NGT for major adverse cardiovascular event rates was 2.65 (95% CI 1.37 to 5.15, p=0.004) while the HR of DM to NGT was 3.27 (1.68 to 6.38, p=0.0005). However, Cox HR of IFG to NFG for major adverse cardiovascular event rates was 1.83 (0.86 to 3.87), which was not significant.

CONCLUSION:

In patients with AMI, an abnormal OGTT is a better risk factor for future adverse cardiovascular events than impaired fasting blood glucose.

PMID: 22581733  (added emphasis mine)

In this study, it is the rise in blood glucose after meals that is associated with bad outcomes, not the fasting levels.

Study Finds 20% Increased Risk of Stroke with Impaired Glucose Tolerance

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A new study published in the British Medical Journal examined whether a finding of pre-diabetes was associated with increased risk for stroke. In this study, they analysed data from 15 studies that were done previously.

BMJ. 2012 Jun 7;344:e3564.

Effect of pre-diabetes on future risk of stroke: meta-analysis.

Lee M, Saver JL, Hong KS, Song S, Chang KH, Ovbiagele B.  Chang Gung University College of Medicine, Chang Gung Memorial Hospital, Chiayi, Taiwan.

LINK to Abstract

The results:

  • They did not find that having an elevated FASTING blood sugar in the range defined as pre-diabetes* was associated with an increased risk of stroke when they adjusted for other known cardiovascular risk factors, such as high blood pressure or abnormal blood lipids (cholesterol, triglycerides).  (*100 – 125 mg/dl in some of the studies and 110 – 125 mg/dl in the other studies)
  • They did find an increase risk for stroke of 20% (confidence limits 7% to 35%) in those with impaired glucose tolerance in the pre-diabetes range (whether there was also elevated fasting glucose or not).

Impaired glucose tolerance means that blood glucose goes too high after the person consumes a large amount of glucose (usually as a special drink given at a medical lab).  This would indicate that the blood glucose would also tend to go up after a meal that contained a lot of glucose-yielding food (sugars, starch and, to a much lesser extent protein).  The test for impaired glucose tolerance does not give detailed enough information to be able to predict for an individual exactly how much the blood glucose might go up after any specific meal of actual foods.  For that, a person’s blood has to be tested after the meal to see the blood glucose response.

Take Home Message: Know how high your blood glucose levels go up after meals.  How up is up? At what level of rise of glucose should one be concerned?      Ah, now that is the question.

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Restoring normal blood glucose levels associated with less progression to type 2 diabetes

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A study just published in Lancet found that, in people with pre-diabetes, getting their blood glucose levels back to normal was associated with a cut by half in the number who went on to develop type 2 diabetes during the study period.

Coverage by BBC  LINK

Abstract of the research paper, Lancet site  LINK

With 35% of the US population age 20 years and older estimated to have pre-diabetes, it is urgent to understand this issue.  (The US stats are easy to get and among the highest, but certainly this is a major issue developing all over the world.)

The next step is recognition that a major tool to achieve the goal of normal blood glucose is control over the form and amount of carbohydrates eaten, and that post-meal self-testing will reveal each person’s requirements, in balance with their personal choices and circumstances.  This will bring normalization of blood glucose levels into the reach of almost all of those with pre-diabetes and diabetes (provided they have access to the resources and care needed), while enabling the least use of medication and therefore the least risk of medication side-effects.

There are three factors to be teased out here (the usual, more research needed):

  • the degree to which having lower levels of glucose in the blood lessened progression of damage to the insulin secreting cells of the pancreas, or other damaging effect of glucose levels above normal
  • the degree to which some people were less able to achieve normal blood glucose levels because of strictly physical factors, such as how much damage they already had to the insulin-secreting cells of the pancreas. (That is, the degree to which the people who achieved normal blood glucose were a different group of people than the ones who did not achieve normal blood glucose.  In that case, the ability to return to normal blood glucose levels would be a “marker” that distinguishes one group at less risk from another group at more risk – rather that being a “cause” of protection or progression)
  • the degree to which the people who did not achieve normal blood glucose readings were less engaged in trying to improve their blood glucose levels, which might suggest that they are people who do not take as much care of their health in other ways.

Curiously (or not curiously at all, when you think about it), among those who did not return to normal blood glucose levels, the group assigned to “intensive lifestyle” changes fared worse that the placebo group.  Why could that be?  It is highly likely that part of what they were taught as “intensive lifestyle intervention” was the usual higher carb, low-fat diet.

“Among participants who did not return to normal glucose regulation in DPP, those assigned to the intensive lifestyle intervention had a higher diabetes risk (HR 1·31, 95% CI 1·03—1·68, p=0·0304) and lower chance of normal glucose regulation (OR 0·59, 95% CI 0·42—0·82, p=0·0014) than did the placebo group in DPPOS.”

I hope this study gets wide media attention and that it spurs much more investigation into the damaging effects of “non-diabetic” levels of high blood glucose.

Early Diabetes Detection – Not helpful? Oh?

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“BUZZ … It’s Not Working…”  (Toy Story)

Study results suggest early detection by screening of Type 2 diabetes was not helpful when considering the out-come 12 years later.  This suggests perhaps the medical care given misses the threshold of effectiveness needed in order for that extra early care to be useful in the long term.

The results suggests current interventions, as achieved in clinical practice, are not enough to take advantage of earlier diagnosis accomplished through screening.

This study does not at all mean that treatment is not useful.  It asks the question of whether they could demonstrate any long-term benefit of finding Type 2 diabetes by a screening program. This meant the diabetes was discovered about 3 years earlier. The group of people they were compared to were people who’s diabetes had been diagnosed without having a screening test.  This means the doctor had some reason to be suspicious of diabetes and ordered the tests (e.g. symptoms of diabetes, noted to be at risk e.g. family history, abdominal obesity, disease that could be a complication of diabetes e.g. neuropathy, heart attack) or the diabetes was diagnosed during care for another problem.

If the treatment given REDUCES, but does not fully STOP what is causing the progression of disease or the mechanism by which the disease is causing damage, then finding it earlier (and thus giving that treatment for more years) is not going to reduce the long-term outcome.

You might think of it as there being, just to pick a descriptive concept for the sake of discussion, 6 levels of aggressiveness or types of the damaging effect of Type 2 diabetes on health.  In that example, level 6 impact would be falling into a coma from extreme uncontrolled high blood sugars. What if regular medical care as it is currently undertaken helps with the more aggressive damage from diabetes, but does not stop the level 1 or the level 1 and 2  or type of damaging impact?  What if in the early years of diabetes, when it is not as likely to be diagnosed, there is mostly level 1 and level 2 damage? If such were the case, then knowing about the diabetes earlier and instituting the current care would not help, if it didn’t stop the level 1 or level 1 and 2 damage anyway.

Of course, all studies have their limitations.  This is a rather small study.  You can see it as meaning that diagnosing Type 2 diabetes earlier is not helpful, because people are going to get just as much harm over the long term, anyway.  Or you can see it as meaning that what is done with that information (“this person has Type 2 diabetes”) is not enough to halt the contribution to harm that is caused during those earliest years.

There is something else to think of.  If the damage from blood sugar elevations is actually starting at much lower levels than we look for and treat for, then perhaps the damage is accumulating over, say, 15 years or 20 years or 25 years before diagnosis of full-blown diabetes.  In that case, intervening 3 years earlier is not many years in the over-all time frame.

Once again the question, do we need to use (and achieve!) substantially lower targets for glucose control than are currently recommended or are currently accomplished (or considered acceptable) in the clinical setting (that is, what actually occurs as patients interact with their doctors).  Would that have made the difference to the health of the people in this study?  We don’t know. The study does not answer that question.  All studies have their problems and so the answer to the question of ”why these study results” always remains somewhat in a “black box”.  It is even possible that it could be simply that problems with the study design produced misleading results.  Back to the perennial “more research is needed”.

Link to Abstract and Full Text of this study:  LINK

Diabetologia. 2012 Jun;55(6):1651-9. Epub  2012 Jan 12.

How much does screening bring forward the diagnosis of type 2 diabetes and reduce complications? Twelve year follow-up of the Ely cohort.

Rahman M, Simmons RK, Hennings SH, Wareham NJ, Griffin SJ.

Source General Practice and Primary Care Research Unit, University of Cambridge, Cambridge, UK.

Abstract

AIMS:

There are continuing uncertainties about how much screening for type 2 diabetes brings forward the clinical diagnosis and the impact that earlier diagnosis has on health outcomes. We compared the duration of diabetes and health outcomes in a population invited for diabetes screening at 5-yearly intervals from 1990 (screened population) with those in a similar population not invited for screening (unscreened population).

METHODS:

This was a parallel-group, cohort study of people aged 40-65 years, free of known diabetes, identified from the population register of a general practice in Ely, Cambridgeshire, UK (n = 4,936). In 1990-1992, one-third (n = 1,705), selected randomly, received an invitation for screening for diabetes and cardiovascular risk factors at 5-yearly intervals (screened population). From the remainder of the sampling frame, 1,705 randomly selected individuals were invited to diabetes screening 10 years later (unscreened population). Patients with diabetes from both populations were invited for a health assessment, including biochemical, anthropometric and questionnaire measures, and testing for the presence of diabetic complications

RESULTS:

Of the 199 eligible individuals with diabetes diagnosed during follow-up, 152 (76%) attended for health assessment. The median duration of clinically recognised diabetes was significantly longer in cases arising in the screened (5.0 years) compared with the unscreened population (1.7 years; p = 0.006). Clinical measures, prescribed medication and functional status were similar between screened and unscreened populations.

CONCLUSIONS:

Diabetes screening resulted in cases being identified on average 3.3 years earlier, a difference significantly shorter than previous estimates. Earlier diagnosis did not appear to impact on health outcomes. Further evidence is needed to justify the introduction of population-based screening.

PMID: 22237689

Carpe Your Blood Sugar, new blog

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What if the urgent public health issue of the day is less obesity itself and more about the elevated blood sugar (glucose) levels that occur in the majority of those with higher amounts of body fat?

What if the true cut-off level for concern is less than the target values now used for screening tests, diagnosis and for management targets in diabetes?

What if the urgency comes from the combination of two factors:

  • the fact that at last estimate about half (46%) of the adult population in the US (for example, but other countries are headed in the same direction) have pre-diabetes or diabetes, and
  • these elevated glucose levels are now optional for the majority of people, because a different approach to management can be used (at least, for those who have access to regular medical care and the personal resources to manage a care plan involving self-monitoring of blood glucose).

What if having similarly elevated blood glucose levels (including below the threshold for diagnosis of diabetes) means that people who are classed as ‘normal’ body weight face many of the most worrisome health issues that we have incorrectly been blaming on the total body fat itself?

What if swings in blood glucose are itself a major driver of weight gain and those swings can be eliminated?

Metabolic Syndrome is a term used for a cluster of related medical problems or health indicators that have at their core a reduced ability for the body to handle glucose.  The root causes for this have not yet been understood, so we can’t say that we have a way to treat or correct the source cause of the metabolic syndrome itself.  But we can succeed in keeping the blood glucose in the normal range, and thus largely interfere with the means by which the metabolic syndrome causes damage.

Among the experts in obesity, there is a sea change over the past few years moving towards the realization that the amount of extra fat itself is not the major driver of the degree of health impact of the obesity.  Yes, there are physical impacts of simply being a larger size, such as stress on the joints.  At very high levels of body fat, there can be other serious effects of the physical size, such as strain on the heart and fluid accumulation in the legs.  Certainly we must keep in mind and be very aware that there are emotional impacts, which are related to such factors as weight-based discrimination and (unfairly) feeling personally inadequate for not loosing weight when surrounded by the attitude that it should be so easy.  There are also economic impacts, including discrimination in the work place.

But there is an “illness” aspect that the obesity experts refer to.  Some people who are overweight or obese are actually quite healthy in their metabolism. It is thought that these are not the ones who are headed (at least, not any more than usual) for heart attack, stroke, cancer or the other “illness” consequences that we have come to consider to be caused by high body fat itself. Having a high amount of body fat is not a sole determiner for whether someone is more at risk of these outcomes than someone of “normal” body weight.

Metabolic syndrome is thought to be the major part of the difference, as well as some other factors, such as inflammatory molecules coming from body fat stores, most particularly those in the abdomen.  Control of blood glucose levels, it could be argued, is the most readily attainable change that can be implemented at this time.

Blood sugar levels respond very quickly, in a matter of days, weeks or, at most, months when a well-designed and individually adjusted program is instituted that focuses on reducing the intake of glucose-producing foods, adjusted to create an eating plan that the individual finds acceptable as a long-term aspect of their medical care.

My new web site and blog has been set up as a place to consider these ideas, the relevant research, the experiences of clinicians, the input of people affected by high blood glucose and the implications for individuals and for public health.

www.carpeyourbloodsugar.com

Still in infant form, please visit “Carpe your blood sugar”.

Review of Diet 101 by Jenny Ruhl

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My review on Amazon of Jenny Ruhl’s new book:

Diet 101: The Truth About Low Carb Diets

“This book is a natural continuation on from the author’s on-line interactions and blogging that led to her remarkable contribution Blood Sugar 101. There has been a perception that the main value of choosing to change the amount or type of carbohydrates (sugars and starches) in your diet is as a weight loss diet. Also, there has been a perception that this strategy is only valuable if applied very strictly – and this strict application then means that many people find it too difficult to keep up over time.

In Diet 101, Jenny Ruhl emphasises the fact that the greatest value from controlling carbs is in keeping blood sugars within the normal, non-damaging range. What if you’re not diabetic? Many people who do not meet the cut-off blood sugar test levels to be diagnosed with diabetes have blood sugar levels, at least for parts of the day, that are associated with slowly-accumulating harm to health. This problem is very widespread in our society.

What to do? This damage can be avoided, or at least lessened, by changing your intake of carbohydrate foods – by just as much as you need to and/or are able to. Even changes less than targeting perfection can bring benefits you might really value.

Jenny Ruhl explains all this in her new book in a clear, easy to understand manner, with all the back-up science also available for those who are interested. Also, she ties the excess swings in blood sugar to excess hunger drive and the tendency to gain weight. To be useful, this needs to be practical day-to-day, which is an important goal and strength of the book.”

For more information, see the links to Jenny Ruhl’s Blood Sugar 101 website and her Facebook page in the sidebar.  Also, find links regarding her books and link to interviews on the “Resources” page.

A blog reporting glucose impact of low-carb products and recipes

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This site helps fill a need. Low Carb Review is a new site dedicated to reporting the results of one person’s test trials of low carb foods and products.  Gary Noreen reports the part that matters, which is the rise in blood sugar after eating.  His test subject is himself, but, being an engineer, he takes a very careful approach.

Each person’s blood sugar responses can be unpredictably different, but still this is helpful and a valiant contribution.

I think the pumpkin and ricotta cheese breakfast dish is tempting (he refers to this as pumpkin “cereal”).  You can click through from his site to the recipe, which he found on About.com Low Carb Diets.

Low Carb Review lcreview.org

Read some of his story of using a low-carb diet and post-meal testing to manage his diabetes for 19 years without complications (and find the link to the rest of his story) under the “Stories” button.

Impact of high blood glucose on vascular events and death

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This study is just published.  When looking at this study, there are four key factors to consider:

  • This is a study that looks at correlation, it does not specifically test cause. People who had evidence of sustained exposure to higher blood glucose levels had worse outcomes, for whatever mix of reasons.
  • This study did not look at micro-vascular disease (such as nerve damage, kidney damage or eye damage) or rate of deterioration of glucose control, so the study does not say that there might not be health benefit from achieving a HgA1c of less than 6.5%
  • I’ll have to wait to see the full text of the study (and consider input from others who will doubtless publish commentary) to consider what further might be said of this study. For example, the fact that the results of the study did not suggest a protective effect from having HgA1C below 6.5% could be related to low numbers of the study group reaching such a relatively good level of control – although this was probably accounted for. Only further examination of the full study report will tell.
  • Also, HgA1C is only one way of looking at blood glucose levels.  It does not give information about aspects of blood glucose that vary between people, such as the degree of elevation of fasting glucose versus glucose spikes after meals.
Diabetologia. 2012 May 26.

Relationship between HbA(1c) levels and risk of cardiovascular adverse outcomes and all-cause mortality in overweight and obese cardiovascular high-risk women and men with type 2 diabetes.

Andersson C, van Gaal L, Caterson ID, Weeke P, James WP, Couthino W, Finer N, Sharma AM, Maggioni AP, Torp-Pedersen C.

Department of Cardiology, Gentofte University Hospital of Copenhagen, Niels Andersens vej 65, 2900, Hellerup, Denmark, ca@heart.dk.

Abstract

AIMS/HYPOTHESIS:

The optimal HbA(1c) concentration for prevention of macrovascular complications and deaths in obese cardiovascular high-risk patients with type 2 diabetes remains to be established and was therefore studied in this post hoc analysis of the Sibutramine Cardiovascular OUTcomes (SCOUT) trial, which enrolled overweight and obese patients with type 2 diabetes and/or cardiovascular disease.

METHODS:

HRs for meeting the primary endpoint (nonfatal myocardial infarction, nonfatal stroke, resuscitated cardiac arrest or cardiovascular death) and all-cause mortality were analysed using Cox regression models.

RESULTS:

Of 8,252 patients with type 2 diabetes included in SCOUT, 7,479 had measurements of HbA(1c) available at baseline (i.e. study randomisation). Median age was 62 years (range 51-86 years), median BMI was 34.0 kg/m(2) (24.8-65.1 kg/m(2)) and 44% were women. The median HbA(1c) concentration was 7.2% (3.8-15.9%) (55 mmol/l [18-150 mmol/l]) and median diabetes duration was 7 years (0-57 years). For each 1 percentage point HbA(1c) increase, the adjusted HR for the primary endpoint was 1.17 (95% CI 1.11, 1.23); no differential sex effect was observed (p = 0.12 for interaction). In contrast, the risk of all-cause mortality was found to be greater in women than in men: HR 1.22 (1.10, 1.34) vs 1.12 (1.04, 1.20) for each 1 percentage point HbA(1c) increase (p = 0.02 for interaction). There was no evidence of increased risk associated with HbA(1c) ≤6.4% (≤46 mmol/l). Glucose-lowering treatment regimens, diabetes duration or a history of cardiovascular disease did not modify the associations.

CONCLUSIONS/INTERPRETATION:

In overweight, cardiovascular high-risk patients with type 2 diabetes, increasing HbA(1c) concentrations were associated with increasing risks of cardiovascular adverse outcomes and all-cause mortality.  PMID: 22638548

Do you know where your blood sugar climbs after eating?