Dozens of morbidly obese Kiwis have shed two-thirds of their weight after a rare surgical procedure, new research shows.
But one patient also died after not sticking to their follow-up treatment, and some surgeons are concerned about the risks of the complicated operation.
It comes as surgery becomes an increasingly common option for treating obesity, with hundreds of publicly funded operations a year.
More than a third of the adult population is now deemed obese.
The latest research, published today in the New Zealand Medical Journal, shows that 36 patients who had a duodenal switch shed, on average, 72 per cent of their weight within a year.
The average patient came into surgery weighing 150kg and within a year had dropped to 52kg.
In addition, the North Shore Hospital research found nine out of 10 patients no longer had diabetes, and most were rid of sleep apnoea and hypertension.
The duodenal switch requires two operations. The first removes about 70 per cent of the stomach and the second, more complicated, creates two separate pathways in the small intestines. The smaller stomach gets full faster, limiting consumption, while the second change limits the fat and calories the body absorbs.
North Shore Hospital is the only hospital in New Zealand performing the operation, and bariatric surgeon Hisham Hammodat is one of the few surgeons trained in the procedure.
Hammodat said the surgery had been around since the 1980s but had been used in New Zealand only since 2008, with about 70 people having the operation.
Despite some risks, the research showed the duodenal switch was more effective in shedding weight and curing diabetes than alternative surgery.
"But it is something that we reserve for the morbidly obese," he said.
People who had the surgery must take vitamin supplements daily for the rest of their lives.
One patient died from liver failure nine months after the operation after not sticking to the vitamins, Hammodat said.
Capital & Coast DHB bariatric surgeon Kusal Wickremesekera does not perform the surgery, and said generally he would not recommend it. The requirement for ongoing vitamins meant it was only practical for the extremely obese. "It does increase the weight loss, but can lead to other problems."
'I'd be dead now if I had not lost that weight'
Penny Harrison knew she was going to die if she did not do something about her weight.
About four years ago, the 45-year-old Auckland woman was morbidly obese and living with diabetes. But a heart attack and triple bypass caused her to fear for her life.
She read about the duodenal switch, a rare weight-loss operation, and decided she needed to take drastic steps.
In 2011, she went under the knife at North Shore Hospital, having part of her stomach removed and her intestine redirected.
Three years later, she said the surgery was not the magic bullet she had hoped for. She has lost 38 kilograms but remains obese despite dieting and regular exercise.
But, while she might never be size 10, she said the surgery saved her life. It had cured her diabetes and had given her a new lease of life.
"I would be dead by now if I had not lost that weight."
Natalie Jacka, a student from West Auckland, also had the procedure in 2011 at North Shore Hospital with even more dramatic results. When she went into surgery, she weighed 156kg. Today she weighs just 72kg.
It was difficulty with pregnancy and her first daughter's birth and that pushed her towards surgery.
"If I didn't have that surgery, I don't think I would have lived to see [daughter] Kara's 21st birthday."
- The Dominion Post
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