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Diabetes Treatment Risk Not Found in 2nd Study
One week after U.S. researchers announced that pushing down blood sugar levels as close as possible to normal might be dangerous for high-risk diabetes patients, a preliminary analysis of a similar international study has found no such risk.
The seemingly conflicting findings, released yesterday, stoked the uncertainty about the best strategy for treating Type 2 diabetes, one of the most common health problems in the United States and elsewhere.
\"This unfortunately just makes things more confusing,\" said Richard Kahn of the American Diabetes Association. \"I think patients will be confused. I think doctors will be confused. So I think the message is: 'Don't do anything until we get this sorted out.' \"
Federal health officials said there is a variety of possible explanations for the differing findings, and they planned to meet with their counterparts at the international study to try to explain the results.
\"Hopefully when we sit down and look at the data, we'll come up with some mutual conclusions,\" said Denise Simons-Morton of the National Heart, Lung and Blood Institute.
More than 21 million Americans have Type 2 diabetes, which has become increasingly common because of the obesity epidemic. The disease causes blood-sugar levels to rise abnormally high, making patients prone to a host of complications, including blindness, nerve damage, kidney failure, heart attacks and strokes.
Patients typically try to lower their blood sugar through diet and exercise, or by taking drugs such as insulin or metformin, and researchers have long thought that getting blood-sugar levels as close to normal as possible would be most beneficial.
Last week, researchers at the National Institutes of Health surprised experts when they announced their preliminary analysis of an ongoing study involving more than 10,000 patients in the United States and Canada. They found 54 more deaths in the group that had intensive therapy to lower their blood-sugar levels than in the group that received standard treatment. The finding prompted organizers to halt the part of the study in which subjects were receiving the most intensive treatment.
The announcement about the U.S.-based study, known as Accord, prompted a panel monitoring a similar study known as Advance to conduct a preliminary analysis of its own data, which involve more than 11,000 patients in Europe, Asia and Canada, said study director Anushka Patel of the George Institute for International Health in Australia.
\"Because of the Accord results, we felt we needed to ask our data safety and monitoring board to look at the data,\" Patel said. Like the Accord trial, the Advance study involved patients at high risk for heart problems. The patients were 66 years old on average.
The Advance analysis found no similar increase in deaths among patients receiving the most intense therapy for an average of five years, she said.
\"There is no sign of the increased mortality that was apparently evident in the Accord study,\" Patel said in a telephone interview. \"It's reassuring.\"
She added that no additional information was available, including whether the study showed any benefit from more intensive treatment.
\"We have to wait until we have the full data to make any conclusions about the benefits and risks,\" Patel said.
Other researchers said it was difficult to interpret the findings before seeing details of both studies, which have not been published. Although the two studies were similar, there may be important differences in the patients studied or the treatments they received, they said.
\"There's a lot we don't know,\" said John Buse, also of the American Diabetes Association and a member of the committee overseeing the Accord trial.
The patients in the Advance trial, for example, received a drug that is not available in the United States, Buse said. They could also have been healthier in some ways.
Another key issue is the specific blood-sugar levels achieved by the two studies, Buse and others said.
Blood-sugar levels are measured by a blood test known as hemoglobin A1C. The patients receiving intensive treatment in the Advance trial achieved a median A1C level of 6.4, compared with 7 for those on standard treatment, Patel said. While the levels achieved by intensive treatment in the two studies were similar, the level achieved by the standard treatment in the Accord trial was slightly higher, which could possibly account for the difference in outcomes, several experts said.
\"That difference in the spread could make a difference,\" said Kahn, adding that he hopes the situation will become clearer when the full results are published along with a third similar trial expected later this year.
\"I think between the three of them, we'll be able to sort it out,\" he said.
鉴于美国研究人员在一周前报道，对于那些高危的糖尿病患者，将血糖降至接近正常可能是危险的，但是后来的一项类似研究的初期结果并没有得出相同的结论。这两项几乎是矛盾的研究结果，再一次将2型糖尿病的最佳治疗方案推到了风尖浪口上。
上周，国立健康研究中心宣布的一个研究结果让很多专家大跌眼镜——包含了来自美国和加拿大的超过10000人的Accord研究的初期结果显示，相比于接受标准降糖治疗的研究组，接受强化降糖治疗的研究组中的死亡人数多了54人。该结果迫使研究人员不得不停止了其中最严格的强化治疗研究项目。
来自美国糖尿病协会的Richard Kahn评价：“很不幸的，这样的研究结果只是让事情更加复杂，让医生和患者都更加烦恼；但在得出最终结论之前，这个研究结果不会影响大家”。联邦健康部门的官员说，对于这样差异的结果，有很多种不同的解释，他们准备在一项国际试验中与其他研究人员一起解开这个谜底。国立心肺血液研究所的Denise Simons-Morton说，希望当大家坐下来研究数据的时候，可以得出一些共识。
由于肥胖的流行，目前美国罹患糖尿病的人数已经超过了2100万，日益流行。这个疾病会导致血糖升高，然后引发一系列的并发症，如失明、神经损害、肾衰、心脏病或中风。一般来说，患者会通过饮食控制、运动锻炼及采用二甲双胍、胰岛素之类的药物来降低血糖，研究人员们长期以来也认为，将血糖降至接近正常是最有益的。
Accord的研究结果促使委员会重新审视另一项类似的研究，力图从它的初期数据中找出一些线索，这项名为Advance的研究囊括了来自欧洲、亚洲和加拿大的近11000名研究对象，澳大利亚的专家称。正是因为Accord研究出现了这样的结果，Advance的研究人员觉得有必要申请安全和监测委员会去审查研究数据，因为他们纳入的研究对象也是那些存在心脏高风险的患者，平均年龄为66岁。但是，最终在Advance研究中没有得出类似的结论，在平均5年的时间里，接受最严格强化治疗的患者没有出现更多的死亡，并没有出现类似Accord研究中明显增高的死亡率。但同时，也没有获得其他的信息，研究结果也没有表明强化治疗有什么益处。
现在，只有等待最终的完整的数据来评价其收益和风险了。其他的研究人员认为，在看到这两个试验的具体细节之前，很难解读结果，但是试验的细节并没有公布。他们认为，虽然两项试验非常相似，但是在试验对象和他们接受的治疗措施方面肯定有很大的差异。Advance研究中的患者服用了一种在美国拿不到的药物，而且，这些患者在某一方面可能更为健康。
另一个关键的问题是两项试验的血糖水平。众所周知，衡量血糖水平的标准是HbA1C。Advance研究中，强化治疗组的达到的HbA1C中位数是6.4%，标准治疗组是7%；而在Accord试验中，虽然强化治疗组的达标线和Advance研究类似，但是标准治疗组的标准确实稍微高一些，这可能与最终结果的差异有关，一些专家认为。
距离上的差异导致了结果的差异，但是希望，待包括今年下半年的第三项研究的全部数据公布之后，情况可以明晰一些。 |
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发表于 2008-3-1 07:03:17