24Drs好健康報:肥胖手術風險該如何預測？
好健康熱頭條 ─ 肥胖手術風險該如何預測？ How to Predict Obesity Surgery Risk
好健康小單字 – 胃繞道手術（Gastric bypass surgery，GBS）
好健康熱頭條 ─ 肥胖手術風險該如何預測？
今年大約有200,000名美國人將接受減肥手術，其中大部分的人將展開更為健康的生活，不幸的是，有部分患者最後終難免一死。
現在，一項由杜克大學胃繞道減肥手術外科醫師所研發的評估工具，應能協助醫師在評估死亡風險最低和最高的患者是哪些人時，有更佳的診斷率。
Eric DeMaria醫師和研究同仁以其獨到的觀察及相關領域中其他人的研究為基礎，於去年率先提出風險評估系統。
由觀察得到以下5個因子，是較差之外科手術結果的獨立預測指標：
* 手術患者為男性
* 年齡長於45歲
* BMI值高於50
* 高血壓
* 肺部形成血栓的風險較高
不具任何上述危險因子或具備1項的患者，被視為是會因減肥手術死亡之低風險族群；而具備2至3項危險因子的患者，則落於中度風險區間內，而有4至5項危險因子的患者，則被視為高風險。
為確認其提出的風險評估系統是有效的，DeMaria醫師和研究同仁分析4,433名患者的資料，這4,433名患者曾於三所醫學中心接受減肥手術；DeMaria醫師將研究發現發表於科羅拉多州科泉市召開的美國外科協會年會中。
他指出，發生手術相關的死亡病例，在2,166名被歸類為低度風險患者的有8名，在2,142名被歸類為中度風險患者的有26名，而在125名中被歸類為高度風險患者的有3名。
雖然高度風險患者占總手術比例的不到3%，但他（她）們比起沒有風險因子的最低度風險族群，死亡風險卻高出6倍。
【死亡人數數據為何？】
接受減肥手術的患者，最後會因為手術而病逝的人數到底有多少並不清楚；美國政府近期的報告指出，手術後的立即死亡率於2004年為0.19%，那已是從1998年的0.89%降下來了。
不過，一項於2005年對接受減肥手術之美國醫療保險計劃受領者的研究發現，65歲及更年長的患者，在接受手術30天內的死亡風險為5%，而男性的死亡風險為3.7%。
清楚的是，現在接受胃繞道減肥手術的人，比起數年之前要多出許多。
美國肥胖手術學會主席Philip R. Schauer醫師向WebMD表示，1995年之前，每年進行僅約10,000項的減肥手術，而近年來（每年）則做到高達200,000項。
Schauer醫師認為新的風險評估模型是個好的開始，但他也表示，它離會影響手術因子的完整清單還差得很遠。
他表示，這群研究人員能夠找出5項重要的危險因子，不過，總共可能有20項、甚至更多；舉例來說，罹患慢性實質性炎症（cirrhosis）的患者，手術結果可能會很差，我們仍需要更大規模的研究加以確認，因為慢性實質性炎症相對而言並不常見。
【「不算很讓人吃驚」】
該項風險評估工具能協助患者更瞭解自己特定的危險為何，但DeMaria醫師和Schauer醫師都同意，若自己屬「高風險族群」，那並不代表不應該接受減肥手術；兩位醫師指出，事實上，這些人可能是會獲得最大利益的患者群，因為他（她）們的死亡風險已經很高了。
DeMaria醫師向WebMD表示，這些患者有高手術風險並不很讓人吃驚，他們較有可能罹患共存性疾病，像是糖尿病及心血管疾病，因此他（她）們的非手術性風險可能非常高。
Schauer醫師引用一項近期的研究，該研究追蹤接受胃繞道減肥手術的患者術後8年，並將他（她）們和未接受減重手術的病態性肥胖者進行比較，即使有發生手術死亡案例，接受胃繞道減肥手術的患者死亡率還是低了65%。
他指出，當患者和其醫師談到接受手術的風險，他（她）們也得討論不接受手術可能會帶來的風險。
【愈早接受手術愈好嗎？】
DeMaria醫師表示，Eric DeMaria醫師研究團隊的獨到觀察，也可用來確定那些落在低度風險類的患者，並協助患者及其醫師評估延後手術所可能造成的衝擊。
於DeMaria醫師新提出的研究報告中，低度風險患者的死亡率為0.2%至0.3%；他表示，由此觀之，那樣的風險可說極低，從總人口數的角度來看，在他（她）們接受減重手術前，應該就已在鬼門關徘徊了的這種論點應被揚棄；較合理的是，對較年輕、較健康的患者，在他（她）們因肥胖而產生健康問題前，提供了接受減重手術的機會。
How to Predict Obesity Surgery Risk
About 200,000 Americans will have weight loss surgery this year, and while most will go on to lead healthier lives, tragically, some patients will die as a result.
Now a new assessment tool developed by a Duke University gastric bypass surgeon should help doctors better identify patients with the lowest and highest risk of death.
Eric DeMaria, MD, and colleagues first proposed the risk assessment system last year, based on their own observations and those of others in the field.
The observations led them to conclude that these five factors are independent predictors of poorer surgical outcome:
• Being male
• Age over 45
• Having a body mass index of more than 50
• Having high blood pressure
• Having a high risk for developing blood clots in the lungs
Patients with none or one of the risk factors were considered to have a low risk of death from weight loss surgery. Those with two to three factors fell into the medium-risk range, and those with four or five were considered high risk.
In an effort to validate the system, DeMaria and colleagues examined data from 4,433 patients who had weight loss surgeries at three centers.
DeMaria presented findings from the study at the annual meeting of the American Surgical Association in Colorado Springs, Colo.
He reported that surgery-related deaths occurred in eight of the 2,166 patients classified as low risk, 26 of the 2,142 patients in the medium-risk group, and three of the 125 patients classified as high risk.
While high-risk patients made up less than 3% of the total surgical population, they had a sixfold greater risk of death than patients categorized at the lowest risk who had no risk factors.
How Many Die?
It is not clear how many patients who have weight loss surgeries ending up dying from the procedures. A recent government report found death rates immediately following surgery to be 0.19% in 2004 -- down from 0.89% just six years earlier.
But a 2005 study of Medicare recipients who had weight loss surgeries found a 5% risk of death among patients aged 65 and older within 30 days of surgery and a 3.7% risk of death for men.
What is clear is that many more people are having gastric bypass surgery than even just a few years ago.
"Prior to 1995, only about 10,000 surgeries were performed each year, and now we are up to about 200,000 [annually]," American Society for Bariatric Surgery President Philip R. Schauer, MD, tells WebMD.
Schauer calls the new risk assessment model a good starting place, but he says it is far from a complete list of factors that could influence surgical outcome.
"These researchers were able to identify five important risk factors, but there may be 20 or more," he says. "For example, patients with cirrhosis might have very poor surgical outcomes, but we would need bigger studies to figure this out because cirrhosis is relatively rare."
'No Big Surprise'
The risk assessment tool can help patients better understand their specific risk. But DeMaria and Schauer agree that being 'high risk' doesn't mean that a patient should not have weight loss surgery.
In fact, these are the patients who could benefit most, they say, because their risk of death is already so high.
"It is no big surprise that these patients have a high surgical risk," DeMaria tells WebMD. "These are the patients who more than likely have co-morbid conditions like diabetes and cardiovascular disease, so their nonsurgical risk is probably pretty high, too."
Schauer cites a recent study that followed gastric bypass patients for eight years after surgery and compared them to morbidly obese people who did not have weight loss surgery. Even with surgical deaths, the bypass patients had a 65% lower mortality rate.
"When patients talk to their doctors about the risks of having surgery, they also need to talk about the risks of not having surgery," he says.
The Earlier the Better?
The observations could also be used to reassure patients who fall into the low-risk category and to help patients and their doctors assess the impact of delaying surgery, DeMaria says.
The mortality rate among low-risk patients in his newly reported study was 0.2% to 0.3%.
"That is very, very low risk," he says. "From a population standpoint it argues in favor of giving up the notion that people should be on death's door before they have weight loss surgery. It makes more sense to offer it to patients who are younger and healthier before they develop the health problems that are associated with the disease of obesity."
SOURCES: American Surgical Association annual meeting, Colorado Springs, Colo., April 26, 2007. Eric DeMaria, MD, director, Duke Endosurgery Center. Philip R. Schauer, MD, president, American Society for Bariatric Surgery; director, Bariatric and Metabolic Institute, Cleveland Clinic. Agency for Healthcare Research and Quality, Statistical Brief #23, Health and Human Services. JAMA, Oct. 19, 2005; vol 294.
WebMD Medical News
By Salynn Boyles
Reviewed by Brunilda Nazario, MD
好健康小單字 – 胃繞道手術（Gastric bypass surgery，GBS）
胃繞道手術為時下的減肥手術之一，最早是從美國和義大利盛行開來，該項手術除了使胃囊容積減少、限制進食量外，胃腸繞道也會減少營養吸收，因此不僅有減重的效果，也兼顧維持體重，但因屬侵入性醫療，多少有風險及後遺症，故不宜貿然進行，須先經醫師評估過身心狀況後，才能確保安全。
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