Diabetes: Cardiovascular Risk Higher Than Once Thought
Diabetes: Cardiovascular Risk Higher Than Once Thought
According to the American Diabetes Association (ADA), there are approximately 17 million people in the United States who have diabetes, a condition in which the body is unable to produce enough insulin to properly convert glucose into energy. Early-onset diabetes, or type 1 diabetes, is genetically determined and affects a small minority of these patients. Far more prevalent, affecting > 90% of the diabetic population, adult-onset, or type 2, diabetes usually develops in adults over the age of 45 and is most common among adults over age 65 (Figure).
In 1999, the Centers for Disease Control (CDC) reported that 450,000 annual deaths occurred among the diabetic population, a figure representing about 19% of all deaths that year in the United States. Adults with diabetes have heart disease death rates 2 to 4 times higher than those without diabetes. Finally, the increased risk of death and mortality rates associated with diabetes are compounded by the fact that many diabetic individuals are unaware that they suffer from the metabolic disorder.
Diabetes has garnered even more attention recently, particularly with the emergence of new data indicating that the risk of cardiovascular disease events in diabetics may be higher than once suspected. Recognizing its increased incidence and prevalence, researchers have focused on examining the correlation between diabetes and cardiovascular risk, ways to combat the disease, and a means by which to educate the public regarding the devastating effects of the disease.
At every turn, cardiovascular disease -- especially cardiovascular mortality -- stalks the diabetic patient. When matching diabetic to nondiabetic patients in heart disease trials, diabetic patients have always fared worse. This was illustrated by researchers from the Duke Clinical Research Institute (Durham, North Carolina), who performed a posthoc analysis of data from the ill-fated Sibrafiban vs Aspirin to Yield Maximum Protection from Ischemic Heart Events Post Acute Coronary Syndromes I and II (SYMPHONY I and II) "super aspirin" trials (sibrafiban vs aspirin). Presented at this year's 51st Annual Scientific Session of the American College of Cardiology, the Duke team discovered that when all cardiovascular risk factors are equal, the mortality rate among diabetic patients was more than twice that of nondiabetic persons. In fact, diabetic subjects fared worse at every end point than their nondiabetic counterparts.
In their analysis, the Duke researchers noted that mortality risk appears to correlate directly with choice of therapy for diabetes. They found that there was a 2.6-fold increased risk of death for patients taking injected insulin and sulfonylurea drugs, compared with insulin-sensitizing therapies, such as metformin. In addition, they found that at 90 days into the trials, 12% of diabetic patients on insulin-providing therapy had a major adverse event, compared with 5% of diabetic patients on insulin-sensitizing therapy. The researchers said such findings suggest that lowering glucose does not translate into lowering cardiovascular risk and that elevated blood sugar levels may be a marker for, rather than a causative factor in, cardiovascular disease.
The diabetes-cardiovascular disease link is not "new" -- a comprehensive review published more than a year ago in Hypertension, Journal of the American Heart Association presented evidence that diabetes is associated with a 7-fold increase in risk for developing cardiovascular disease. Coupled with other recent findings, the confirmed negative association between diabetes and cardiovascular disease, indicate that aggressive management of blood pressure is just as important as tight glycemic control.
New data from the Nurses Health Study (NHS), published in the July issue of Diabetes Care, underline the need for a new focus on "silent" risks and prediabetic conditions in susceptible individuals. After 20 years of observing the incidence of type 2 diabetes, heart disease, and stroke among 117,629 female nurses, researchers from the Harvard School of Public Health (Boston, Massachusetts) found that cardiovascular risk can increase even before the onset and diagnosis of diabetes. The new NHS data reveal that women who eventually developed type 2 diabetes had a risk of heart attack almost 4 times higher than those who never developed the disease. It was also noted that once women were diagnosed (ie, the type 2 diabetes became manifest), the risk of heart disease increased to 4.5 times that of nondiabetic persons. The same trend held with respect to risk of stroke, where undiagnosed diabetic individuals had more than twice the risk of stroke as those who were never diagnosed with the disease. Researchers attribute such findings to insulin resistance, a prediabetic condition in which the body fails to efficiently respond to insulin.
In addition to tracking the prediabetic conditions of women within the study, researchers also examined the correlation between weight gain/obesity and the onset of coronary heart disease (CHD). During the 20-year follow-up period of the NHS, there were 418 incident cases of CHD, and after adjusting for other risk variables, increased body mass index (BMI) was significantly associated with a higher cardiovascular risk among diabetic women. While not significant, there was also a positive trend between increasing BMI prior to onset of diabetes and the increase of risk. Such findings prompt the need to further evaluate weight loss following diagnosis.
One way to combat the deleterious cardiovascular effects associated with diabetes is to properly identify those at particularly high risk. Researchers from the large UK Prospective Diabetes Study (UKPDS) have developed a mathematical model that incorporates diabetes-specific clinical variables to determine the absolute risk of a first stroke in those with type 2 diabetes. The clinical variables used to determine risk include:
The mathematical model has been integrated in the UKPDS Risk Engine software, and researchers report that the widely available risk calculator is the first to give an approximate "margin of error" for each estimate.
In a recent article in The Lancet, Swedish researchers reported that testing patients with previous myocardial infarction (MI) for signs of diabetes before they leave the hospital may identify those with the highest risk of future MIs. Acknowledging the correlation between increased risk of MI and the presence of diabetes, researchers examined the blood sugar irregularities of MI patients who had yet to be diagnosed with diabetes. They found that 31% of 181 MI patients tested at hospital discharge for blood sugar abnormalities were diagnosed with diabetes and 35% with signs of prediabetes -- and these rates were maintained 3 months following discharge.
A third study, published in the Journal of the American College of Cardiology in July, notes that the presence of silent MI and microalbuminuria levels at baseline may be predictors of future coronary events in patients with type 2 diabetes who are asymptomatic for CHD. The 2 variables were examined in 86 patients with type 2 diabetes and no history of CHD. On univariate analysis, the following were identified as predictors of CHD events:
Interestingly, of the 45 patients diagnosed with silent MI, 15 patients experienced a total of 23 coronary events, and silent MI was found to be the most sensitive predictor of events. However, researchers believe that combining silent MI and microalbuminuria results allowed them to identify patients at particularly high and low risk for coronary events.
When the American Heart Association codified the diabetes-cardiovascular link by listing diabetes as a risk factor for heart disease, researchers began an all-out hunt for vascular clues to explain the link. Now a study in the May 14th issue of JAMA suggests that the critical clue may be found in the human eye.
Researchers from the National University of Singapore reported that narrowing of microvasculature in the retina signals increased risk for type 2 diabetes, even in the absence of other risk factors. Lead investigator Tien Yin Wong, MD, believes the finding suggests that narrowing in retinal arteries may play a role in the development of diabetes. Wong and his colleagues recorded images of the retinas of nearly 8000 healthy men and women aged 49 to 73 years, and measured the extent of narrowing in the small vessels carrying blood to the eye.
Over the next 3.5 years, nearly 4% of the group was diagnosed with diabetes, and narrowing at baseline was associated with increased risk. Importantly, individuals with the narrowest retinal arteries were 71% more likely to develop diabetes than those with the least amount of narrowing, regardless of their blood sugar and insulin levels, family history of diabetes, blood pressure, and other risk factors. The researchers postulated a role for this microvascular change in the etiology of diabetes, suggesting that narrow arteries may make it difficult for the hormone insulin to move sugar out of the blood system and into muscle, where it is used as fuel. However, it is also possible that the artery narrowing is just the first warning sign of a disease that has not yet caused obvious symptoms.
Subtle changes in microvasculature are not the only "silent" symptom associated with diabetes. A study presented at the Society of Nuclear Medicine Annual Meeting suggests that diabetic patients may have deficits in oxygen transport that are not associated with typical cardiac symptoms. The study involved 189 persons with diabetes whose cardiac functioning was assessed by a standard electrocardiogram (EKG) as well as a nuclear stress test (single photon emission computed tomography [SPECT] myocardial perfusion imaging). This test assessed cardiac functioning while each person was at rest, and also when each person's heart was "stressed" by the body's greater need for oxygen-rich blood during exercise. Results from the study showed that more than half of the patients were experiencing cardiac ischemia when the heart was under stress, though the EKG picked up cardiac abnormalities in only about 14% of the patients. The researchers suggested that diabetic patients might be at increased risk for cardiac events during exercise or stress testing even though they experience no chest pain.
In the final twist of fate, some diabetes treatments have been linked with exacerbation of cardiovascular disease and as a result are now coming under close scrutiny. Glitazone therapy, commonly prescribed for treatment of diabetic patients, has been associated with fluid retention as well as plasma volume expansion. A retrospective analysis of insurance claims from 35 health insurers covering 1.7 million Americans examined the association between glitazones and an increased risk for heart failure. Thomas Delea, PhD, and colleagues at Policy Analysis Inc. (Brookline, Massachusetts) used the insurance records to identify 8288 people with diabetes taking glitazones and 41,440 who did not take the drugs. Delea then compared claims over a 36-month period from the time of the first prescription for a glitazone. At a mean of 8.5 months follow-up, risk of developing heart failure was 4.5% in glitazone patients, compared with 2.6% in controls. After controlling for obesity, high blood pressure, and smoking, glitazone use remained an independent predictor for heart failure, and compared with nonusers, there was still a 50% increase in risk of heart failure.
Other studies (including the SYMPHONY-I and -II data from Duke) linked the use of sulfonylurea drugs to an increased risk of coronary spasms. In the July 15th issue of the Journal of Clinical Investigation, researchers from the University of Chicago Hospitals & Health System (Chicago, Illinois) reported that mice that were genetically altered to remove functional potassium channels in the smooth muscle of their coronary arteries have increased levels of calcium, commonly associated with coronary spasms. In a murine model, the spike in calcium triggered severe and sometimes fatal spasms. Sulfonylurea drugs, the researchers suggest, could have a similar effect as the missing gene in the study because they interfere with the potassium channels in the pancreas, an effect that increases insulin levels. Researchers are now suggesting, however, that the increase comes at the price of deleterious effects on smooth muscle cells in coronary arteries, and this, they suggest, may be the trigger for the sulfonylurea-associated coronary artery spasms.
Despite the fact that clinicians are aware of the correlation between diabetes and heart disease, the message is not translating well into clinical practice and is not reaching the patients. Earlier this year, an analysis of data from the Third National Health and Nutrition Examination Survey (NHANES III) found that more than two thirds of adults with diabetes have hypertension, but only 57% are receiving treatment for the condition. Researchers from the CDC examined data from 1507 patients with diabetes and compared those data to the treatment goal -- 130/85 mm Hg -- established by the Sixth Joint National Commission on the Detection, Evaluation and Prevention of High Blood Pressure (JNC-VI). The findings were discouraging:
These disturbing numbers may be just the tip of the iceberg, according to survey data from the ADA, which involved 900 clinicians including cardiologists, endocrinologists, and primary care physicians. Ninety percent of the physicians accurately stated the cardiovascular risk associated with diabetes and said they regularly warned patients about the risk of heart disease, but physicians report that patients routinely minimize cardiovascular risk, ranking it lower than the risk for amputation or blindness. The survey also found that doctors were less likely to aggressively manage hypertension and hypercholesterolemia in a diabetic patient than in a patient with a history of MI, even though the risk for future events is equivalent for these 2 groups. Nonetheless, diabetic patients were less likely to achieve either blood pressure or cholesterol goals. Obesity also is less likely to be aggressively targeted when the patient has diabetes, even though weight loss is associated with improved glycemic control, reductions in blood pressure, and improvements in total cholesterol.
Further documentation of the fact that individuals do not recognize risk was indicated by another survey conducted earlier this year by the Association of Black Cardiologists. Of the 1200-plus African Americans and Hispanics surveyed, > 40% of those with type 2 diabetes did not consider the condition to be related to heart disease; instead, they attributed the condition to their ethnicity.
Recognizing the need for a full-court press aimed at educating diabetic patients about cardiovascular risk, the National Diabetes Education Program (NDEP), an alliance between the National Institutes of Health and the CDC, launched a public service campaign that admonishes diabetic individuals to know their "A, B, Cs," with "A" signifying hemoglobin A1c < 7; "B" referring to blood pressure < 130/80 mm Hg; and "C" representing low-density lipoprotein (LDL) cholesterol level < 100. However, James Gavin, MD, Chair of the NDEP and a past president of the ADA, warned in June that there are still huge gaps in both education and knowledge.
One way to lessen the risk of diabetes may lie in what patients eat and drink. Although many clinicians discourage the use of alcohol in diabetic patients, Japanese researchers report that consumption of 1 or 2 drinks a day reduces the risk of coronary artery disease in people with type 2 diabetes. In a study of 200 adults with diabetes, researchers found an association between light to moderate alcohol consumption and decreased coronary artery stiffness.
The researchers asked study participants about their typical weekly alcohol consumption and used aortic pulse wave velocity to gauge stiffness in the aorta. They found that, on average, light drinkers (defined in this study as up to a couple of drinks per day) had less aortic stiffness than nondrinkers or heavier drinkers. Heavier drinkers also had higher blood pressure and triglyceride levels compared with those who drank less or not at all, according to the report. Drinkers and nondrinkers showed no difference with regard to their recent average blood sugar levels, but researchers cautioned that individuals with diabetes should not drink on an empty stomach, as this can trigger a drop in blood sugar. Interestingly, although other researchers have reported a link between modest alcohol intake and blood thinning as well as higher levels of HDL, the Japanese researchers did not find a similar association among the diabetic patients studied.
Diet, too, can provide benefits for persons with diabetes. The most obvious benefit is weight loss, but data from a study of 3000 middle-aged adults suggest that a diet rich in whole-grain foods may lower the risk of heart disease and type 2 diabetes. The study, reported in the August issue of the American Journal of Clinical Nutrition, found that fiber-rich diets were associated with increased insulin sensitivity and lower serum LDL. Not surprisingly, people who consumed the most whole-grain foods had lower body mass indices.
Diabetics are at higher risk of heart disease
Even prior to diagnosis, cardiovascular risk is high
Assessing readily-available clinical variables may help determine future risk
Which comes first: diabetes or microvascular disease?
Some diabetes treatments may increase cardiovascular risk
Clinicians are spreading the word, but patients may not be listening
The right foods and a few drinks may add up to a prevention strategy
According to the American Diabetes Association (ADA), there are approximately 17 million people in the United States who have diabetes, a condition in which the body is unable to produce enough insulin to properly convert glucose into energy. Early-onset diabetes, or type 1 diabetes, is genetically determined and affects a small minority of these patients. Far more prevalent, affecting > 90% of the diabetic population, adult-onset, or type 2, diabetes usually develops in adults over the age of 45 and is most common among adults over age 65 (Figure).
In 1999, the Centers for Disease Control (CDC) reported that 450,000 annual deaths occurred among the diabetic population, a figure representing about 19% of all deaths that year in the United States. Adults with diabetes have heart disease death rates 2 to 4 times higher than those without diabetes. Finally, the increased risk of death and mortality rates associated with diabetes are compounded by the fact that many diabetic individuals are unaware that they suffer from the metabolic disorder.
Diabetes has garnered even more attention recently, particularly with the emergence of new data indicating that the risk of cardiovascular disease events in diabetics may be higher than once suspected. Recognizing its increased incidence and prevalence, researchers have focused on examining the correlation between diabetes and cardiovascular risk, ways to combat the disease, and a means by which to educate the public regarding the devastating effects of the disease.
At every turn, cardiovascular disease -- especially cardiovascular mortality -- stalks the diabetic patient. When matching diabetic to nondiabetic patients in heart disease trials, diabetic patients have always fared worse. This was illustrated by researchers from the Duke Clinical Research Institute (Durham, North Carolina), who performed a posthoc analysis of data from the ill-fated Sibrafiban vs Aspirin to Yield Maximum Protection from Ischemic Heart Events Post Acute Coronary Syndromes I and II (SYMPHONY I and II) "super aspirin" trials (sibrafiban vs aspirin). Presented at this year's 51st Annual Scientific Session of the American College of Cardiology, the Duke team discovered that when all cardiovascular risk factors are equal, the mortality rate among diabetic patients was more than twice that of nondiabetic persons. In fact, diabetic subjects fared worse at every end point than their nondiabetic counterparts.
In their analysis, the Duke researchers noted that mortality risk appears to correlate directly with choice of therapy for diabetes. They found that there was a 2.6-fold increased risk of death for patients taking injected insulin and sulfonylurea drugs, compared with insulin-sensitizing therapies, such as metformin. In addition, they found that at 90 days into the trials, 12% of diabetic patients on insulin-providing therapy had a major adverse event, compared with 5% of diabetic patients on insulin-sensitizing therapy. The researchers said such findings suggest that lowering glucose does not translate into lowering cardiovascular risk and that elevated blood sugar levels may be a marker for, rather than a causative factor in, cardiovascular disease.
The diabetes-cardiovascular disease link is not "new" -- a comprehensive review published more than a year ago in Hypertension, Journal of the American Heart Association presented evidence that diabetes is associated with a 7-fold increase in risk for developing cardiovascular disease. Coupled with other recent findings, the confirmed negative association between diabetes and cardiovascular disease, indicate that aggressive management of blood pressure is just as important as tight glycemic control.
New data from the Nurses Health Study (NHS), published in the July issue of Diabetes Care, underline the need for a new focus on "silent" risks and prediabetic conditions in susceptible individuals. After 20 years of observing the incidence of type 2 diabetes, heart disease, and stroke among 117,629 female nurses, researchers from the Harvard School of Public Health (Boston, Massachusetts) found that cardiovascular risk can increase even before the onset and diagnosis of diabetes. The new NHS data reveal that women who eventually developed type 2 diabetes had a risk of heart attack almost 4 times higher than those who never developed the disease. It was also noted that once women were diagnosed (ie, the type 2 diabetes became manifest), the risk of heart disease increased to 4.5 times that of nondiabetic persons. The same trend held with respect to risk of stroke, where undiagnosed diabetic individuals had more than twice the risk of stroke as those who were never diagnosed with the disease. Researchers attribute such findings to insulin resistance, a prediabetic condition in which the body fails to efficiently respond to insulin.
In addition to tracking the prediabetic conditions of women within the study, researchers also examined the correlation between weight gain/obesity and the onset of coronary heart disease (CHD). During the 20-year follow-up period of the NHS, there were 418 incident cases of CHD, and after adjusting for other risk variables, increased body mass index (BMI) was significantly associated with a higher cardiovascular risk among diabetic women. While not significant, there was also a positive trend between increasing BMI prior to onset of diabetes and the increase of risk. Such findings prompt the need to further evaluate weight loss following diagnosis.
One way to combat the deleterious cardiovascular effects associated with diabetes is to properly identify those at particularly high risk. Researchers from the large UK Prospective Diabetes Study (UKPDS) have developed a mathematical model that incorporates diabetes-specific clinical variables to determine the absolute risk of a first stroke in those with type 2 diabetes. The clinical variables used to determine risk include:
Duration of diagnosed diabetes;
Age at diagnosis;
Gender;
Current smoking status;
Systolic blood pressure;
Ratio of total high-density lipoprotein (HDL) cholesterol; and
Presence of atrial fibrillation.
The mathematical model has been integrated in the UKPDS Risk Engine software, and researchers report that the widely available risk calculator is the first to give an approximate "margin of error" for each estimate.
In a recent article in The Lancet, Swedish researchers reported that testing patients with previous myocardial infarction (MI) for signs of diabetes before they leave the hospital may identify those with the highest risk of future MIs. Acknowledging the correlation between increased risk of MI and the presence of diabetes, researchers examined the blood sugar irregularities of MI patients who had yet to be diagnosed with diabetes. They found that 31% of 181 MI patients tested at hospital discharge for blood sugar abnormalities were diagnosed with diabetes and 35% with signs of prediabetes -- and these rates were maintained 3 months following discharge.
A third study, published in the Journal of the American College of Cardiology in July, notes that the presence of silent MI and microalbuminuria levels at baseline may be predictors of future coronary events in patients with type 2 diabetes who are asymptomatic for CHD. The 2 variables were examined in 86 patients with type 2 diabetes and no history of CHD. On univariate analysis, the following were identified as predictors of CHD events:
Baseline ankle brachial index;
Silent MI;
Microalbuminuria;
10-year Framingham heart disease risk > 30%; and
Fibrinogen levels.
Interestingly, of the 45 patients diagnosed with silent MI, 15 patients experienced a total of 23 coronary events, and silent MI was found to be the most sensitive predictor of events. However, researchers believe that combining silent MI and microalbuminuria results allowed them to identify patients at particularly high and low risk for coronary events.
When the American Heart Association codified the diabetes-cardiovascular link by listing diabetes as a risk factor for heart disease, researchers began an all-out hunt for vascular clues to explain the link. Now a study in the May 14th issue of JAMA suggests that the critical clue may be found in the human eye.
Researchers from the National University of Singapore reported that narrowing of microvasculature in the retina signals increased risk for type 2 diabetes, even in the absence of other risk factors. Lead investigator Tien Yin Wong, MD, believes the finding suggests that narrowing in retinal arteries may play a role in the development of diabetes. Wong and his colleagues recorded images of the retinas of nearly 8000 healthy men and women aged 49 to 73 years, and measured the extent of narrowing in the small vessels carrying blood to the eye.
Over the next 3.5 years, nearly 4% of the group was diagnosed with diabetes, and narrowing at baseline was associated with increased risk. Importantly, individuals with the narrowest retinal arteries were 71% more likely to develop diabetes than those with the least amount of narrowing, regardless of their blood sugar and insulin levels, family history of diabetes, blood pressure, and other risk factors. The researchers postulated a role for this microvascular change in the etiology of diabetes, suggesting that narrow arteries may make it difficult for the hormone insulin to move sugar out of the blood system and into muscle, where it is used as fuel. However, it is also possible that the artery narrowing is just the first warning sign of a disease that has not yet caused obvious symptoms.
Subtle changes in microvasculature are not the only "silent" symptom associated with diabetes. A study presented at the Society of Nuclear Medicine Annual Meeting suggests that diabetic patients may have deficits in oxygen transport that are not associated with typical cardiac symptoms. The study involved 189 persons with diabetes whose cardiac functioning was assessed by a standard electrocardiogram (EKG) as well as a nuclear stress test (single photon emission computed tomography [SPECT] myocardial perfusion imaging). This test assessed cardiac functioning while each person was at rest, and also when each person's heart was "stressed" by the body's greater need for oxygen-rich blood during exercise. Results from the study showed that more than half of the patients were experiencing cardiac ischemia when the heart was under stress, though the EKG picked up cardiac abnormalities in only about 14% of the patients. The researchers suggested that diabetic patients might be at increased risk for cardiac events during exercise or stress testing even though they experience no chest pain.
In the final twist of fate, some diabetes treatments have been linked with exacerbation of cardiovascular disease and as a result are now coming under close scrutiny. Glitazone therapy, commonly prescribed for treatment of diabetic patients, has been associated with fluid retention as well as plasma volume expansion. A retrospective analysis of insurance claims from 35 health insurers covering 1.7 million Americans examined the association between glitazones and an increased risk for heart failure. Thomas Delea, PhD, and colleagues at Policy Analysis Inc. (Brookline, Massachusetts) used the insurance records to identify 8288 people with diabetes taking glitazones and 41,440 who did not take the drugs. Delea then compared claims over a 36-month period from the time of the first prescription for a glitazone. At a mean of 8.5 months follow-up, risk of developing heart failure was 4.5% in glitazone patients, compared with 2.6% in controls. After controlling for obesity, high blood pressure, and smoking, glitazone use remained an independent predictor for heart failure, and compared with nonusers, there was still a 50% increase in risk of heart failure.
Other studies (including the SYMPHONY-I and -II data from Duke) linked the use of sulfonylurea drugs to an increased risk of coronary spasms. In the July 15th issue of the Journal of Clinical Investigation, researchers from the University of Chicago Hospitals & Health System (Chicago, Illinois) reported that mice that were genetically altered to remove functional potassium channels in the smooth muscle of their coronary arteries have increased levels of calcium, commonly associated with coronary spasms. In a murine model, the spike in calcium triggered severe and sometimes fatal spasms. Sulfonylurea drugs, the researchers suggest, could have a similar effect as the missing gene in the study because they interfere with the potassium channels in the pancreas, an effect that increases insulin levels. Researchers are now suggesting, however, that the increase comes at the price of deleterious effects on smooth muscle cells in coronary arteries, and this, they suggest, may be the trigger for the sulfonylurea-associated coronary artery spasms.
Despite the fact that clinicians are aware of the correlation between diabetes and heart disease, the message is not translating well into clinical practice and is not reaching the patients. Earlier this year, an analysis of data from the Third National Health and Nutrition Examination Survey (NHANES III) found that more than two thirds of adults with diabetes have hypertension, but only 57% are receiving treatment for the condition. Researchers from the CDC examined data from 1507 patients with diabetes and compared those data to the treatment goal -- 130/85 mm Hg -- established by the Sixth Joint National Commission on the Detection, Evaluation and Prevention of High Blood Pressure (JNC-VI). The findings were discouraging:
Overall, 71% of the sample had hypertension, but risk increases with age and 83% of diabetic persons older than age 65 have hypertension.
Among those with clinically confirmed hypertension, 29% said they were unaware of the diagnosis.
Only 43% of the diabetic patients currently receiving treatment for hypertension had achieved the JNC-VI goal, which is slightly less than the control rate (45%) achieved by nondiabetic adults.
These disturbing numbers may be just the tip of the iceberg, according to survey data from the ADA, which involved 900 clinicians including cardiologists, endocrinologists, and primary care physicians. Ninety percent of the physicians accurately stated the cardiovascular risk associated with diabetes and said they regularly warned patients about the risk of heart disease, but physicians report that patients routinely minimize cardiovascular risk, ranking it lower than the risk for amputation or blindness. The survey also found that doctors were less likely to aggressively manage hypertension and hypercholesterolemia in a diabetic patient than in a patient with a history of MI, even though the risk for future events is equivalent for these 2 groups. Nonetheless, diabetic patients were less likely to achieve either blood pressure or cholesterol goals. Obesity also is less likely to be aggressively targeted when the patient has diabetes, even though weight loss is associated with improved glycemic control, reductions in blood pressure, and improvements in total cholesterol.
Further documentation of the fact that individuals do not recognize risk was indicated by another survey conducted earlier this year by the Association of Black Cardiologists. Of the 1200-plus African Americans and Hispanics surveyed, > 40% of those with type 2 diabetes did not consider the condition to be related to heart disease; instead, they attributed the condition to their ethnicity.
Recognizing the need for a full-court press aimed at educating diabetic patients about cardiovascular risk, the National Diabetes Education Program (NDEP), an alliance between the National Institutes of Health and the CDC, launched a public service campaign that admonishes diabetic individuals to know their "A, B, Cs," with "A" signifying hemoglobin A1c < 7; "B" referring to blood pressure < 130/80 mm Hg; and "C" representing low-density lipoprotein (LDL) cholesterol level < 100. However, James Gavin, MD, Chair of the NDEP and a past president of the ADA, warned in June that there are still huge gaps in both education and knowledge.
One way to lessen the risk of diabetes may lie in what patients eat and drink. Although many clinicians discourage the use of alcohol in diabetic patients, Japanese researchers report that consumption of 1 or 2 drinks a day reduces the risk of coronary artery disease in people with type 2 diabetes. In a study of 200 adults with diabetes, researchers found an association between light to moderate alcohol consumption and decreased coronary artery stiffness.
The researchers asked study participants about their typical weekly alcohol consumption and used aortic pulse wave velocity to gauge stiffness in the aorta. They found that, on average, light drinkers (defined in this study as up to a couple of drinks per day) had less aortic stiffness than nondrinkers or heavier drinkers. Heavier drinkers also had higher blood pressure and triglyceride levels compared with those who drank less or not at all, according to the report. Drinkers and nondrinkers showed no difference with regard to their recent average blood sugar levels, but researchers cautioned that individuals with diabetes should not drink on an empty stomach, as this can trigger a drop in blood sugar. Interestingly, although other researchers have reported a link between modest alcohol intake and blood thinning as well as higher levels of HDL, the Japanese researchers did not find a similar association among the diabetic patients studied.
Diet, too, can provide benefits for persons with diabetes. The most obvious benefit is weight loss, but data from a study of 3000 middle-aged adults suggest that a diet rich in whole-grain foods may lower the risk of heart disease and type 2 diabetes. The study, reported in the August issue of the American Journal of Clinical Nutrition, found that fiber-rich diets were associated with increased insulin sensitivity and lower serum LDL. Not surprisingly, people who consumed the most whole-grain foods had lower body mass indices.