HbA1c predicts CVD in hypercholesterolemic patients
MedWire News: Risk for cardiovascular disease (CVD) increases linearly with glycated hemoglobin (HbA1c) level in hypercholesterolemic individuals, Japanese researchers report.
The authors say their research is the first to demonstrate the significant relationship between elevated HbA1c and increased risk for CVD in hypercholesterolemic patients.
They also report that the link is independent of pravastatin therapy, and suggest that appropriate HbA1c management in addition to lipid lowering is therefore required in these patients.
As reported in the journal Cardiovascular Diabetology, Rimei Nishimura (Jikei University School of Medicine, Minato-ku, Tokyo) and team analyzed the relationship between HbA1c and CVD using clinical data from the MEGA (Management of Elevated Cholesterol in the Primary Prevention Group of Adult) study conducted in Japan between 1994 and 2004.
The MEGA Study included 7832 patients aged 40-70 years, with mild-to-moderate hypercholesterolemia without CVD, who were randomized to either a diet group (National Cholesterol Education Program step I diet) or a diet plus pravastatin (10-20 mg/day) group for a follow-up period of 5 years.
The team stratified data for 4002 of the patients into three categories according to HbA1c levels (<6.0%, 6.0%-<6.5%, or ≥6.5%) during the first year of follow-up.
They used Cox proportional hazards modeling to evaluate the relationship between patients' HbA1c levels and their 5-year incidence of CVD events, comprising myocardial infarction, angina, cardiac and sudden death, a coronary revascularization procedure, stroke, transient ischemic attack, and arteriosclerosis obliterans.
They found that overall, risk for CVD was 2.4 times higher in individuals with HbA1c ≥6.5% than in those with HbA1c <6.0%.
Further analysis showed that the risk for CVD was increased with elevated HbA1c in both the diet-only and diet-pravastatin groups, with respective hazard ratios of 2.2 and 1.8. Similarly, the association was significant in both men and women, in whom HbA1c ≥6.5% was associated with hazard ratios for CVD of 2.1 and 3.0, respectively.
Further analysis showed a continuous risk increase according to HbA1c level in all subpopulations and also indicated that there is no threshold HbA1c level for the association with CVD risk.
"Our results suggest that the HbA1c level should be included in prediction models for CVD risk. Controlling HbA1c independently of lipid management is necessary to reduce the risk of CVD in diabetic patients with elevated HbA1c," Nishimura and team conclude.
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By Sally Robertson