强化降压未能改善糖尿病患者心血管预后

根据美国糖尿病学会(ADA)年会上展示的一项基于大型随机对照试验对糖尿病患者控制心血管风险行动(ACCORD)的数据分析，强化降压和肥胖程度与糖尿病患者的心血管疾病(CVD)预后无关。

亚特兰大市艾莫利大学的Joshua I. Barzilay博士及其同事指出，这项亚组分析与原始血压研究(n=4,733)的结果一致。原始研究显示，对于糖尿病患者，将收缩压控制在120 mmHg以下与控制在标准治疗目标140 mmHg以下的CVD风险无差异。主要CVD预后指标为包括非致死性心肌梗死(MI)、非致死性卒中或CVD死亡的复合终点(N. Engl. J. Med. 2010;362:1575-85)。但原始研究中未校正腰围/身高比值。据推测，与腰围/身高比值高于50%相比，腰围/身高比值低于50%与CVD风险降低相关。

Barzilay博士的团队分析了ACCORD研究血压队列中4,687例可获取腰围/身高比值数据的患者的资料。所有受试者同时患有高血压和糖尿病；47.7%为女性；平均年龄为62.2岁；平均随访时间为4.7年。

结果显示，与标准治疗相比，强化降压未能降低复合CVD风险(Diabetes Care 2012;35:1401-5)。尽管与研究者的假设不同，控制腰围/身高比值四分位数并未影响复合预后指标，但发现有一项研究的次要终点(CVD死亡)与腰围/身高比值四分位数有显著的相关性(最重四分位数与最轻四分位数相比，危险比为2.32；95%置信区间为1.40~3.83；P=0.0009)。其他两项次要预后指标(致死或非致死性卒中和非致死性MI)均未受影响。

这项亚组分析获得了美国国立心肺血液研究所和其他美国联邦机构的资助。除研究药物和设备由不同生产厂家捐赠之外，未报告其他利益冲突。

Aggressive blood pressure lowering, and the degree of a patient’s adiposity, appear unrelated to cardiovascular disease outcomes in individuals with diabetes, according to a new analysis of data from the large, randomized controlled trial, Action to Control Cardiovascular Risk in Diabetes, presented at the annual meeting of the American Diabetes Association in Philadelphia.

The subanalysis follows on findings from the original blood-pressure study (n = 4,733) that showed no difference in cardiovascular disease (CVD) risk between people with diabetes mellitus whose blood pressure was treated to less than 120 mm Hg, compared with those with the standard treatment goal of less than 140 mm Hg. The primary measure of CVD outcomes looked at a composite of nonfatal MI, nonfatal stroke, or CVD death (N. Engl. J. Med. 2010;362:1575-85).

That original study, however, did not control for waist-to-height ratios. Presumably, a waist-to-height ratio of less than 50% would be associated with less CVD risk, compared with a ratio higher than 50%, postulated Dr. Joshua I. Barzilay of Emory University, Atlanta, and his colleagues.

His team analyzed data from the 4,687 people in the ACCORD blood-pressure cohort for whom waist-to-height data were available. All subjects had diabetes and hypertension; 47.7% were women; the subjects’ mean age was 62.2 years; and the mean follow-up was 4.7 years. Intensive lowering of blood pressure did not improve combined CVD risk, compared with standard treatment, they found (Diabetes Care 2012;35:1401-5).

Although the investigators found that controlling for the waist-to-height quartile did not affect risk for the combined outcome measure as they had hypothesized it would, one secondary end point in the study (CVD death) was found to be significantly related to the waist-to-height quartile (hazard ratio, 2.32; 95% confidence interval, 1.40–3.83; P = .0009 comparing the heaviest to lightest quartiles). Neither of the two other secondary outcome measures – fatal or nonfatal stroke and nonfatal MI – was affected.

The association between central obesity and increased risk of CVD death (but not MI or stroke) was “surprising, because morbidity outcomes share similar pathomechanisms with mortality outcomes.”

However, they wrote, the finding was in keeping with some other published studies. Increased “levels of inflammation factors are more strongly associated with fatal than with nonfatal CVD events. Greater degrees of central obesity are related to increased inflammation levels,” they wrote.

The study is limited by its post hoc design, modest number of outcomes measured, and short follow-up. “The power to detect significant differences by the degree of central obesity was limited. With longer follow-up and more events, statistical significance could possibly be achieved for several outcomes.”

The subanalysis was funded by the U.S. National Heart, Lung, and Blood Institute, and other U.S. federal agencies. Aside from study medicines and equipment, which were donated by various manufacturers, no conflicts of interest were reported.