What are they
Ozempic / Semaglutide is a weekly injectable medical therapy that acts as a GLP-1 hormone analogue. It is used to decrease appetite, slow gastric emptying, and promote improved glycaemic regulation.
Sleeve Gastrectomy (SG) is a surgical method in which a significant part of the stomach is removed, resulting in a smaller stomach volume that leads to earlier satiety.
One Anastomosis Gastric Bypass (OAGB) is a form of gastric bypass surgery where a reduced-size stomach pouch is attached to a loop of the small intestine, leading to both restriction of intake and some degree of malabsorption.
| Treatment | Advantages | Disadvantages |
|---|---|---|
| Ozempic |
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| Sleeve Gastrectomy |
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| OAGB |
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Long-Term Outcomes (>3 years)
OAGB has been found to result in higher total weight loss compared to SG at three years, particularly among individuals with higher BMI. For instance, a study of super-obese patients reported approximately 36.5% total weight loss with OAGB versus about 33.2% with SG after three years. In a separate five-year comparison, OAGB was associated with more sustained weight loss, less weight regain or insufficient loss, greater rates of type 2 diabetes remission, and more improvement in sleep apnea compared to SG. However, some patients undergoing SG maintain their weight loss during the initial one to two years, though over time, there is an increased likelihood of weight regain or the need for revisional surgery.
For Ozempic:
Clinical trial and real-world evidence indicate that average weight loss is around 15% or slightly higher when used for obesity (depending on dose and adherence) during the first year. There is limited long-term data beyond two to three years; discontinuation rates are notable due to cost, side effects, or tolerability, which can impact sustained results. Additionally, up to 70% of patients experience weight regain following cessation of the medication.
Tolerance / Side Effects
Ozempic: Gastrointestinal side effects such as nausea, vomiting, and diarrhoea frequently occur, particularly at the beginning of treatment. Some individuals may discontinue use due to these effects. Adherence may be affected, and long-term use can be limited by factors such as cost and the need for continuous medication. Real-world persistence with the medication tends to decrease over time.
SG: There may be challenges in adapting to anatomical changes and food tolerance, with a relatively high risk of reflux (GERD). Some patients require conversion procedures if reflux or weight regain occurs. Nutritional deficiencies, particularly in iron and vitamin B12, can also arise.
OAGB: This procedure carries a greater risk of malabsorption, nutritional deficiencies, ulcers, and possible bile reflux, necessitating increased monitoring of vitamins and minerals. Adjustments in digestion following OAGB may be significant for some patients.
Cost over 3 Years
Here are approximate cost comparisons:
| Treatment | Expected Cost Year 1 | Cost in Years 2-3 | Total 3-Year Cost | Cost-Benefit Considerations |
|---|---|---|---|---|
| Ozempic | The monthly cost for Wegovy/Ozempic in New Zealand is approximately $450-600 per month. This results in a first-year drug cost of about $5,400-7,200, excluding additional doctor or clinic fees and monitoring expenses. | Years 2-3: Ongoing medication costs are about NZD $16,000-22,000+ over three years, not including medical care. Stopping treatment reduces costs but may lead to weight regain. | The estimated cost for many individuals ranges from approximately $16,000 to $25,000 or more over three years, varying according to dosage requirements, adherence, and additional expenses. | Pros: avoids surgery, lower short-term risk, and is more easily reversible. Cons: the cost is high and represents an ongoing financial commitment. Additionally, the cost per kilogram lost tends to be greater unless medication prices decrease or subsidies are available. |
| Sleeve Gastrectomy | The initial surgical expenses range from approximately $19,000 to $25,000, covering hospital fees, surgeon charges, anaesthesia, and related costs. This estimate also incorporates the costs associated with surgical clinics, follow-up appointments, nutritional support, and other necessary services. | Following surgery, expenses typically decrease and are generally limited to regular follow-up appointments, vitamin supplementation, and management of occasional complications. | Over a three-year period and across various situations, the overall cost is typically lower than the combined expense of continuous Ozempic use. After the initial cost of surgery, ongoing expenses are generally reduced. | Cost-effectiveness improves after the initial investment, with better weight loss per dollar and lower comorbidity costs (e.g., fewer diabetes medications). However, risks and potential revisions can increase expenses. |
| OAGB | The initial cost exceeds that of SG, ranging from $20,000 to $25,000, due to factors such as increased procedural complexity, extended surgical duration, potential for longer hospitalisation, and additional preoperative requirements. | The follow-up approach is like that of SG for years 2-3, with an increased cost associated with nutritional supplementation. | The 3-year total cost is generally higher than SG, but still likely less than paying the full drug cost for three years in most situations. | OAGB is associated with greater weight loss and improved remission of comorbidities, which can lead to reduced health-related expenses due to decreased medication needs for conditions such as diabetes and hypertension. However, it is important to also consider the increased risk of nutritional deficiencies or malabsorption-related costs. |
Which might be better and for whom
For individuals seeking modest weight loss who wish to avoid surgery but can commit to ongoing treatment and have the financial means, Ozempic or similar medications may be an appropriate option. These therapies are also beneficial for patients who are not suitable surgical candidates due to increased risk.
However, for those requiring greater weight reduction, more sustainable outcomes, and long-term resolution or improvement of comorbid conditions such as type 2 diabetes mellitus or sleep apnea, surgical interventions—including sleeve gastrectomy (SG) or one-anastomosis gastric bypass (OAGB)—generally demonstrate superior efficacy over medical therapy after three years or more.
When comparing SG and OAGB, OAGB typically results in greater weight loss and higher rates of comorbidity remission, although it is associated with an increased potential for side effects, a higher risk of nutritional deficiencies, and requires more intensive follow-up.
From a cost perspective, surgical procedures are characterized by higher initial expenses, while medical therapy entails ongoing costs. Over a three-year period, cumulative medication expenditures may surpass those of surgery when evaluated per unit of weight loss or quality-adjusted life year.
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