Patients may benefit from lower recommended BMI targets
American College of Cardiology 60th Annual Scientific Sessions
NEW ORLEANS — Recommended normal BMI parameters may be higher than necessary, as new data indicate that CV risk factors increase as BMI increases, beginning with a BMI of 20.
Glenn Lee, MBBS, and colleagues from the National University Health System and Khoo Puat Hospital in Singapore studied more than 3,000 adults who were referred for routine employment health screening for traditional CV risk factors. The mean age of the cohort was 38.9 years; mean BMI was 25.2; and 89.9% were men. The researchers excluded patients with diabetes and vascular disease.
According to the results, the overall prevalence of new diabetes cases was 2.4%. The majority of patients (84.5%) were classified as low risk, using the Framingham Risk Score.
The mean BMI of the cohort was 25.2. Analysis indicated a strong association between BMI and blood pressure, HDL and LDL levels; HDL and LDL levels were significantly worse with a BMI greater than 20. Systolic and diastolic BP rose significantly with a BMI greater than 22. The researchers noted a dose-response relationship for all risk factors, with the exception of LDL levels. Instead, these levels plateaued with a BMI greater than 26.
"Significant dose-response increases in traditional risk factors occurred at a BMI that is well within the normal range. Given the step-wise and additive nature of CV risk factors and the consistent correlation with a rising BMI of above 20, this calls into question what can be considered a truly normal BMI," Lee told Cardiology Today. "That's our major concern. Are we really being too lenient with these recommended guidelines for Caucasian populations (25) and Asian populations (23) or should we lower it?"
Lee also noted that several other studies support their findings, with one trial, which was published in Circulation in 2007 by Razak et al, suggesting that Asians may benefit from lowering the recommended BMI to 21. Another study conducted by Odegaard et al and published in PLoS One also suggested that the normal BMI for nonsmokers aged younger than 65 years should range from 18.5 to 21.4. Lee said this area requires further investigation.
"We would like to investigate and follow this cohort to see if this trend between CV risks and BMI persists as they age, and if these trends translate into increased cardiovascular event and mortality rates," Lee said. – by Melissa Foster
For more information:
Lee G. Poster 1079-304. Presented at: ACC 60th Annual Scientific Sessions; April 2-5, 2011; New Orleans.
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Aspirin use in patients with diabetes requires careful consideration
American College of Cardiology 60th Annual Scientific Sessions
NEW ORLEANS — Aspirin has been proven to be effective in reducing the risk for CV events; however, patients with diabetes are a unique population that requires special considerations before treatment. While aspirin therapy is recommended, further exploration into dosing strategies, stronger antiplatelet therapy and the clinical interaction between aspirin and patients with diabetes is essential, a speaker said here.
“A landmark stage published in 1990 really set the stage as to why diabetics are different and why antiplatelet therapy may be effective in this population,” Jeffrey S. Berger, MD, of the NYU Cardiac and Vascular Institute at the NYU Langone Medical Center in New York, said during a presentation. “Compared with nondiabetics, diabetics had greater platelet activity.”
Berger noted that one study currently being conducted at NYU suggests that markers of platelet activity correspond well with an increasing prevalence of diabetes, even in patients without CVD. Data from other trials support this association, and these results raised an important question: Can measuring platelet activity prevent a future event? At present, this question remains unanswered but warrants further investigation, he said.
In addition, physicians must consider dosing when treating with aspirin. Berger explained that aspirin inhibits COX-1 and, thus, reduces amounts of platelet activation and vascular constriction. However, aspirin at higher doses also reportedly inhibits prostacyclin, which causes an effect opposite of thromboxane. Therefore, Berger emphasized that physicians be careful not to prescribe too much aspirin, even among patients with diabetes.
Many physicians believe that patients with diabetes have a different clinical response to aspirin than those without the disease. Berger pointed out that this is a misconception, however, and cited data from a large meta-analysis that indicated no significant differences in aspirin’s effect on decreasing myocardial infarctions, stroke or all-cause mortality in patients with diabetes compared with those without the disease. Most importantly, he said, research showed no significant interaction in how aspirin prevents CV events between patients with the diabetes and those without.
Despite aspirin’s efficacy in decreasing CV benefits, the medication has been linked with serious adverse events, such as major bleeding, with research showing a low number needed to treat and a low number needed to harm.
“Thinking about it this way, for every 1,000 patients treated for 5 years, three ischemic events are avoided, but three major bleeds are caused,” Berger said. “So when you’re thinking about who should get aspirin, you should think about the absolute benefit and the absolute risk.”
Future studies
Because patients with diabetes are a special population, researchers and physicians should consider whether stronger antiplatelet therapies are required. Berger said future studies must take other medications into account. Statins, fish oil and ACE inhibitors, for example, have antiplatelet activity and this effect may attenuate some of aspirin's effect for patients with diabetes. He also noted that dosing strategies may have to be altered, such as administering aspirin twice a day instead of once daily. Additionally, improved tools for monitoring aspirin’s effect on preventing CV events would also be extremely valuable, according to Berger.
“There is no significant clinical interaction between diabetics and nondiabetics regarding the effect of aspirin. If remains uncertain if diabetics may need a different strategy of dosing or a stronger antiplatelet therapy, and I think future clinical trials should address these issues,” Berger said. – by Melissa Foster
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New analyses yield insufficient data on safety of rosiglitazone
American College of Cardiology 60th Annual Scientific Sessions
NEW ORLEANS — Current evidence remains insufficient to incriminate or exonerate rosiglitazone, on the basis of recent analyses, according to Sanjay Kaul, MD, and George A. Diamond, MD.
The safety of rosiglitazone was questioned in 2007 after a meta-analysis by Steven E. Nissen, MD, and Kathy Wolski, MPH, of the Cleveland Clinic, was published in The New England Journal of Medicine. The original meta-analysis, which included 56 trials of more than 35,000 patients, found a 43% increased risk for myocardial infarction and a 64% increased risk for CV death among rosiglitazone users. Nissen and Wolski recently updated their meta-analysis, and found that rosiglitazone was associated with a 28% greater risk for MI and no associated with CV death.
Because the updated analysis excluded 15 trials on MI and 29 trials on CV death, Kaul and Diamond, both from Cedars-Sinai Medical Center, sought to determine whether these exclusions biased the updated results on the CV safety of rosiglitazone (Avandia, GlaxoSmithKline). They compared the index study with meta-analyses of the 56 trials that were originally included and used different pooling methods.
According to the results, ORs ranged from 1.17 to 1.28 for MI and from 0.94 to 1.03 for CV death.
“Corrected models resulted in smaller ORs and narrower confidence intervals than did uncorrected models,” Kaul and Diamond wrote in their study abstract. “Although corrected risks remain elevated, none are statistically significant, except for the ‘treat as one trial’ method employed by the authors that is prone to bias.”
Further, ORs were nonsignificant when Kaul and Diamond excluded results of the DREAM trial or the seven trials in which rosiglitazone is not indicated or is contraindicated.
“Given the fragility of the data … additional data will be required to adjudicate these inconclusive results,” Kaul and Diamond said. - by Katie Kalvaitis