RYGB的营养预后优于十二指肠转位术

华盛顿-根据在今年的美国外科医师协会临床大会(ACSCC)上展示的一项前瞻性队列研究的结果，尽管胆胰旷置-十二指肠转位术的减重效果较好，但Roux-en-Y胃旁路术与超级肥胖患者的营养预后更佳有关。

研究者对前瞻性收集的350例连续超级肥胖患者的数据进行了回顾性分析，超级肥胖的定义为BMI≥50 kg/m2。这些患者分别接受胆胰旷置-十二指肠转位术(BPD/DS；n=198)或Roux-en-Y胃旁路术(RYGB；n=152)。两个队列是自我选择的，并且性别分布均衡；每组的平均年龄接近41岁。BPD/DS和RYGB组的平均体重指数(BMI)分别为59 kg/m2 和56 kg/m2。BPD/DS组的术前体重高于RYGB组（范围分别为267~597磅和240~505磅）。研究中对每个队列患者的长期营养预后进行了比较。该研究是由芝加哥大学的Marc Ward博士及其同事进行的。

结果显示，尽管BPD/DS组的病死率高于RYGB组，并发症（如大便习惯改变）发生率也较高，BPD/DS与伴发疾病缓解结果更佳相关，且这一结果与体重减轻无关。超级肥胖患者体重减轻程度最多增加了20%。因为BPD/DS手术导致的小肠表面吸收面积减少幅度大于RYGB手术，研究者认为，理论上BPD/DS手术可能导致临床更严重的营养缺乏，在关于操作选择的问题解答患者咨询时，应考虑这一点。

在术后6个月~8年的7个随访时间点，研究者获得了每一组的多个营养参数结果。根据临床指征，给予患者营养补充治疗。Ward博士说，尽管预期BPD/DS组的营养参数数值可能较低，“但我们没有料到，BPD/DS组有75%的患者在4年时维生素A水平低于正常，而RYGB组患者中仅有23%维生素A水平低于正常”。对于其他营养指标，也存在相似的发现：在所有时间点，BPD/DS组的脂溶性维生素D和E以及矿物质硒和锌的营养缺乏也较RYGB组更严重。在1年和3年时，两组铁的数值大致相同，铁缺乏症发生率约为20%，但BPD/DS组的缺乏仍相对更为严重，在8年时，BPD/DS组铁缺乏症发生率为RYGB组患者的2倍以上。但两组的白蛋白、维生素B12、铁蛋白、叶酸和甲状旁腺素水平无统计学差异。

Ward博士指出，患者的低营养素水平“并不一定意味着发生症状或无法进行补充治疗”。

RYGB组仅有1例患者因体重减轻不足接受修正手术，而BPD/DS组有5例患者接受修正手术，原因均为营养不良。

研究者总结认为，对于超级肥胖患者，接受Roux-en-Y胃旁路术较接受胆胰旷置一十二指肠转位术营养预后更佳。

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By: WHITNEY MCKNIGHT, Clinical Endocrinology News Digital Network

WASHINGTON – Despite better excess weight loss outcomes from the biliopancreatic diversion with duodenal switch, the Roux-en-Y gastric bypass procedure was associated with better nutritional outcomes in the superobese, according to the results of a prospective cohort study presented at this year’s American College of Surgeons Clinical Congress.

Investigators retrospectively analyzed data collected prospectively from 350 consecutive superobese patients, who underwent either biliopancreatic diversion with duodenal switch (BPD/DS; n = 198) or Roux-en-Y gastric bypass surgery (RYGB; n = 152), and compared long-term nutritional outcomes in each cohort. The research was conducted by Dr. Marc Ward and his colleagues at the University of Chicago, who presented the results.

The cohorts were self-selected and equally distributed across the sexes; each group’s mean age was just under 41 years. The mean body mass index (BMI) in the BPD/DS group was 59 kg/m2 and was 56 kg/m2 in RYGB. The preoperative body weight in the BPD/DS group was higher than that in the RYGB group (range, 267 lbs to 597 lbs. vs. 240 lbs to 505 lbs, respectively).

Although the BPD/DS had higher morbidity and mortality rates than did the RYGB, as well as more complications, such as altered bowel habits, the BPD/DS is associated with better comorbidity resolution independent of weight loss, and up to 20% greater excess weight loss in superobese patients. Superobesity is defined as having a BMI of 50 kg/m2 and above.

Because the reduction in intestinal absorptive surface area in BPD/DS is greater than in RYGB, the researchers theorized that the resultant nutritional deficiencies might be clinically significant enough to consider when counseling patients on procedure selection.

At seven postoperative follow-up points between 6 months and 8 years, the investigators obtained a variety of nutritional parameters from each group. Patients were given nutritional supplementation as clinically indicated.

Dr. Ward said that while he and his colleagues expected the BPD/DS group to have lower nutritional values, "We didn’t expect that 75% of our patients would have, at 4 years out, a below-normal level of vitamin A, compared to 23% in the RYGB patients."

There were similar surprises for other nutritional markers: At all time points, the BPD/DS group also had significantly more nutritional deficiencies than did the RYGB group in fat-soluble vitamins D and E, and in minerals selenium and zinc. Between years 1 and 3, iron values were near parity at about 20%, although the BPD/DS group was still more deficient, and at year 8 had more than double the rate of iron deficiency as RYGB patients.

Values for albumin, vitamin B12, ferritin, folate, and parathyroid hormone, however, were not significantly different between the two groups. Dr. Ward said that low nutritional values in patients, "does not necessarily mean they are developing symptoms or can’t be treated with supplementation."

Only one RYGB patient underwent revision because of insufficient weight loss, whereas five BPD/DS patients underwent revision, all for malnutrition.

"It’s absolutely crucial for people who elect to have a duodenal switch operation to have long-term, life-long nutritional follow-up," Dr. Ward told the audience. He also said that clinicians should closely evaluate their patients’ level of commitment to compliance over the long-term when discussing bariatric procedures.