DATO certification explained
How the quality of Dutch weight loss surgery is monitored

What is DATO?

DATO records every weight loss operation in the Netherlands: patient characteristics, the procedure, complications and outcomes over time. Because every centre reports in the same way, differences between centres become visible and centres can learn from each other.

To perform weight loss surgery, a centre must meet the standards of the Dutch Society for Surgery, including at least two specialised surgeons and together more than 200 procedures a year.

What the 2024 figures show

In 2024, 1.4 percent of patients nationally had a serious complication. The textbook outcome, the share of patients for whom everything went to plan, ranged from 89 to 99 percent per centre. The largest centre, WeightWorks Clinics, performed 1,598 primary procedures; the smallest, NOK Terneuzen, 203.

What does DATO mean for you as a patient?

It means every centre is measured in the same way and deviations become visible. Feel free to ask a centre about its results. Together with distance, waiting time and contracting by your insurer, that helps you make a well-considered choice.

Patients also contribute: before surgery and yearly up to five years afterwards you fill in the OBESI-Q questionnaire about your experienced health and quality of life.

Strengths and limits of the register

Advantages

Points of attention

Cost and insurance (2026)

DATO participation costs you nothing; it is part of standard care at every centre.

DATO certification: key figures

Key DATO figures 2024

Step by step

1. Registration. Your operation is recorded.
2. Outcome tracking. Complications and results.
3. OBESI-Q. Before surgery and yearly to five years.
4. Annual report. DICA publishes the figures.
5. Improvement. Centres learn from the data.

Read next

• Choosing an obesity clinic — using DATO data
• All 20 centres with volumes — the English home page
• The operation and its risks — context
• Risks and disadvantages — overview

How to use DATO when choosing a centre

Combine the figures with practical factors: travel distance for five years of aftercare, waiting time, contracting by your insurer and whether the centre offers information in English. Ask the centre how it compares with the national average and how it handles complex cases.

Why the Dutch system is closely monitored

All weight loss surgery in the Netherlands takes place in a limited number of certified centres that meet volume standards. Combined with complete national registration, that makes it possible to spot differences between centres and improve care. For patients, it means that the choice of centre is made within a group that all meet the same minimum requirements.

The register also follows patients over several years, including their experienced health via the OBESI-Q. That gives a more complete picture than complication figures alone.

How to read the figures

A national average of 1.4 percent serious complications does not mean your personal risk is exactly that; it depends on your health, BMI and the type of operation. Centres that treat more complex patients may show different figures. Use DATO data as one part of your decision, together with the advice of your GP and the centre's team.

DATO and your own aftercare

Your data is recorded before surgery and during the years of follow-up. By attending your check-ups and filling in the OBESI-Q questionnaire, you help make the national picture complete. That benefits future patients, who can rely on figures that reflect what really happens after surgery.

If you move abroad or to another region, tell your centre, so your follow-up can be continued or transferred. Complete follow-up is one of the reasons the Dutch register is valued internationally.

Questions to ask a centre about quality

How many operations of my type do you perform each year? How do your complication figures compare with the national average? How is aftercare organised, and what happens if a complication occurs outside office hours? A good centre answers these questions openly.

Remember that figures describe groups of patients. Your own team can explain what they mean for you, taking into account your health, your BMI and the operation you are considering.

Frequently asked questions about DATO

Sources

• DATO Annual Report 2024, Dutch Institute for Clinical Auditing (DICA)
• Richtlijn Chirurgische behandeling van obesitas, NVvH

Search terms leading here: DATO Netherlands, Dutch Audit for Treatment of Obesity, bariatric surgery quality Netherlands.

Author: Gijs Bodenstaff. Last reviewed: September 2026.