本帖最後由 lsc0019 於 2009-6-15 22:36 編輯
作者：Caroline Helwick
出處：WebMD醫學新聞
June 1, 2009(義大利米蘭) — 根據發表於歐洲腎臟協會-歐洲透析與移植協會暨國際腎臟協會聯合會議、世界腎臟科研討會中的German Diabetes and Dialysis(4D)研究分析，對於接受血液透析的糖尿病患，醣化血色素(HbA1c)值升高是突發心因性死亡的強烈風險因素。
主要研究者、德國Wurzburg大學的Christiane Drechsler醫師表示，突發心因性死亡是維持透析病患的最大單一死因，佔全部死亡的25%以上。其風險因素之一可能是血糖控制不佳，我們知道這在一般人也會引發心血管共病症。
她解釋，血糖控制不佳會影響發生共病症、電解質不平衡、鉀與鈣通道功能、交感神經活性，這些全都與發生心律不整有關。
4D研究的目標在根據HbA1c值確認突發心因性死亡的風險，以及各種原因的死亡率。
研究者針對1,255名參與4D研究的第2型糖尿病血液透析病患資料進行分析，病患開始時的平均HbA1c值是6.7%± 1.3%，他們被分成以下幾組：正常HbA1c值(<6%)；升高HbA1c值 (≧6%與< 8%)；高HbA1c 值(≧8%)。
在4年的追蹤期間，總共有617名病患死亡，160人屬於突發心因性死亡，200人死於心肌梗塞。
以開始時的HbA1c作為一個連續變項，結果發現與發生猝死有顯著關聯，校正干擾因素之後的風險比(HR)為1.20 (95%信心區間[CI])為1.06-1.37；P< .01)。不過，Drechsler醫師報告指出，HbA1c值與發生心肌梗塞無關(HR，0.95；95% CI，0.84- 1.06；P= .43)。
在類別分析中，相較於正常HbA1c值(<6%)的病患(HRadj，2.25；95% CI，1.32 -3.81)，升高HbA1c值組(≧6%與< 8%)的病患有83%比較可能猝死(HRadj，1.83；95% CI，1.21- 2.78)，高HbA1c 值(≧8%)的病患猝死風險大於兩倍。
正常HbA1c值者的猝死發生率為每100病患-年有3.0，升高HbA1c值組為5.0，高HbA1c 值組為6.3。
Drechsler醫師指出，再者，HbA1c值每增加1%，各種原因的死亡風險顯著增加9% (P= .02)。
在討論時，提到在2008年6月時發表於美國糖尿病協會的ACCORD研究，該研究認為密集的血糖控制對於預防心血管事件沒有幫助。
Drechsler醫師評論表示，這類病患藉由介入達到緊密的血糖控制是否會減少猝死，是一個需要後續研究評估的議題。
未參與本研究的明尼蘇達大學醫學教授、美國腎臟資料系統心血管特殊研究中心主任Charles Herzog醫師指出，影響透析病患猝死的因素有諸多面向，血糖控制只是其中一個。
其他可能的因素包括缺血性心臟病、心肌構造與功能異常、左心室肥大、電解質變化。特別是血清鉀，4D研究的研究人員計畫分析這些類型。
Herzog醫師向Medscape Nephrology表示，4D研究的主要課題之一，瞭解可以治療與不能治療的因素為何。當跨過無法治療的臨界點而變成可以治療的時候就有其意義。本研究與其他研究的證據認為透析病患猝死的主要原因不是冠心病，這對透析病患來說具有不同意義。對一般人有效的介入方法，如statin類藥物，對於透析病患不一定有用。
該研究未接受商業補助。作者們宣告沒有相關財務關係。
2009年世界腎臟科研討會：歐洲腎臟協會-歐洲透析與移植協會(ERA-EDTA)暨國際腎臟協會(ISN)聯合會議：摘要Su251。發表於2009年5月23日。
WCN 2009: Sudden Cardiac Death in Dialysis Patients Related to Poor Glycemic Control
By Caroline Helwick
Medscape Medical News
June 1, 2009 (Milan, Italy) — In diabetic patients on hemodialysis, elevated glycated hemoglobin A1c (HbA1c) appears to be a strong risk factor for sudden cardiac death, according to an analysis from the German Diabetes and Dialysis (4D) Study, presented here at the World Congress of Nephrology, a Joint Meeting of the European Renal Association–European Dialysis and Transplant Association and the International Society of Nephrology.
"Sudden cardiac death is the single largest cause of mortality in maintenance dialysis patients, accounting for over 25% of all deaths," said principal investigator Christiane Drechsler, MD, from the University of Wurzburg in Germany. "One risk factor for this could be poor glycemic control, which we know in the general population leads to the onset of cardiovascular comorbidities."
Poor glycemic control can affect the development of comorbidities, electrolyte balance, the function of potassium and calcium channels, and sympathetic activity, all of which are relevant to arrhythmogenesis, she explained.
The 4D study aimed to determine the risk for sudden cardiac death and all-cause mortality on the basis of HbA1c levels.
Data were analyzed from 1255 hemodialysis patients with type?2 diabetes who were participants in the 4D study. Mean baseline HbA1c for the population was 6.7%?± 1.3%. Patients were divided into the following categories: normal HbA1c levels (<6%); elevated HbA1c levels (? 6% and < 8%); and high HbA1c levels (?8%).
During follow-up, at 4 years, a total of 617 patients died, 160 from sudden cardiac death and 200 from myocardial infarction.
Baseline HbA1c, as a continuous variable, was found to be significantly associated with the occurrence of sudden death, with a hazard ratio (HR), after adjustment for confounders, of 1.20 (95% confidence interval [CI], 1.06?- 1.37; P?< .01). HbA1c levels were not, however, linked to the occurrence of myocardial infarction (HR, 0.95; 95% CI, 0.84?- 1.06; P?= .43), Dr. Drechsler reported.
In categorical analyses, patients with elevated HbA1c levels (between 6% and 8%) were 83% more likely to die of sudden death (HRadj, 1.83; 95% CI, 1.21?- 2.78), and patients with high HbA1c levels (?8%) had a greater than 2-fold risk for sudden death, compared with those with normal HbA1c levels (<6%) (HRadj, 2.25; 95% CI, 1.32? -3.81).
The incidence of sudden death per 100 patient-years was 3.0 for patients with normal HbA1c levels, 5.0 for those with elevated HbA1c levels, and 6.3 for those with high HbA1c levels.
Furthermore, the risk for all-cause mortality significantly increased by 9% for every 1% increase in HbA1c levels (P?= .02), Dr. Drechsler added.
During the discussion, it was noted that the ACCORD study, presented at the American Diabetes Association annual meeting in June 2008, found no benefit of intensive glycemic control in the prevention of cardiovascular events. "Whether interventions achieving tight glycemic control in these patients will decrease sudden death is an issue that needs to be evaluated in future studies," Dr. Drechsler remarked.
Factors affecting sudden death in dialysis patients are likely to be multifactorial, and glycemic control may be one of them, noted Charles Herzog, MD, director of the Cardiovascular Special Studies Center of the US Renal Data System, and professor of medicine at the University of Minnesota in Minneapolis. He was not involved in the study.
Other possible factors include ischemic heart disease, abnormalities in myocardial structure and function, left ventricular hypertrophy, and electrolyte shifts. Serum potassium, in particular, could be a factor, and the 4D investigators plan to analyze these patterns, he said.
"One of the main lessons of 4D is that some factors are treatable and some are not. There may be a point when things that could be treatable early on cross the tipping point and become untreatable," Dr. Herzog told Medscape Nephrology. "There is evidence from this and other studies that the main mechanism of sudden death in dialysis patients is not coronary heart disease, which has a different meaning in dialysis patients. Interventions that work in the general population, such as statins, do not work as well in dialysis."
The study did not receive commercial support. The authors have disclosed no relevant financial relationships.
World Congress of Nephrology 2009: A Joint Meeting of the European Renal Association–European Dialysis and Transplant Association (ERA-EDTA) and the International Society of Nephrology (ISN): Abstract Su251. Presented May 23, 2009. |
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