NSIH-SSI - National surveillance of surgical site infections

The European point prevalence study of healthcare-associated infections and antimicrobial use (2017) indicated for Belgium that surgical site infections (SSI) together with urinary tract infections and lung infections are the three most common types of healthcare-associated infections, with shares of 17%, 21% and 22% respectively of the total prevalence of 7.3%. 

SSI are an important cause of increased morbidity and mortality in patients undergoing surgery. Results of the National SSI Surveillance (2001–2003 results) also showed that the incidence of SSI in patients observed after hernia operations can vary from 0.8% in low-risk patients to more than 8% in high-risk patients. In the group of deep incisional or organ/cavity SSI (37% of all SSI), 34% led to re-operation and 22% to hospital readmission. The mortality rate for the group of patients with this type of SSI was also higher than that of the group that underwent the same surgery but was spared of infections. Surveillance of SSI at local and national level is therefore part of a broad strategy for the prevention of these types of healthcare-associated infections.

The national surveillance of SSI was launched in 2001 with two objectives: 

1. It offers hospitals a standardized protocol and associated means for organizing surveillance within the hospital and following up on the results. 
2. It enables national reference data concerning SSI, its risk factors and outcome parameters to be collected. This enables us to monitor the situation at national level, allowing participating hospitals to position themselves with a group of comparable hospitals or with a comparable patient population.

If a hospital participates in the national surveillance of surgical site infections

We invite general hospitals in Belgium every year to participate in the SSI surveillance on a voluntary basis. As a hospital, you can participate in the SSI surveillance as follows:

• Select at least one surgical procedure from the list of recommended categories of operations (see the surveillance protocol below).
• Organize the follow-up for SSI for the patients who, during the three-monthly surveillance period, have undergone the above-mentioned surgical procedures in your hospital. You can freely choose the three-monthly surveillance period; the definitions and provisions for following up the patients can be found in the surveillance protocol (2010) available in Dutch and French with  addendum in 2017.
• You register the surveillance data via the NSIHwin software (see below) or in data files that you can create yourself (see tools) and send them to Sciensano no later than six weeks after the end of the surveillance period.

How is the data processed and what is the situation regarding confidentiality?

Hospitals provide us with the anonymized surveillance data. After an initial check, we add the submitted data to the national file. We then check whether the data is valid. Finally, we analyze the data at the individual, regional, national and European levels.

We treat individual hospital results with strict confidentiality. No information is disclosed about patient or clinician identities at any time. We only communicate individual results to the actual hospital concerned.

For the organization of SSI surveillance in the hospital, you can, as a hospital, make use of the following tools:

• The current surveillance protocol (2010) (available in Dutch and French with  addendum in 2017) contains detailed explanations of the objectives of the surveillance, the patients and surgical procedures to be followed up and the case definitions used. You will also receive an explanation about the practical organization of the surveillance and how the registrations are to be followed through.
• The NSIHwin software (to be requested from the contact person) for the registration and follow-up of the SSI surveillance data.

The current surveillance protocol (2010/2017) contains the following annexes:

• Reference lists (available in Dutch and French) containing the list of recommended surgical procedures to be registered according to coding of the National Healthcare Safety Network (NHSN), the corresponding procedure codes according to ICD9 CM coding, for each surgery category the list of cutoff values for exceeding operation times and the list of recommended markers to register for antimicrobial resistance.
• The  data definition with a description of all the variables sought in the surveillance. This forms the basis for the registrations instructions (available in Dutch and French) with more explanation about the use of the data definition and the registration forms on paper or in the NSIHwin registration software. Also use the data definition as a guideline if you are creating the surveillance files directly without relying on the software.
• Forms (available in Dutch and French) for paper registration.
• An example of an individual feedback report that is drawn up for a participating hospital after the submission of surveillance data.
• The individual feedback report  manual for correct interpretation of the results.  

An update to the protocol was performed in 2023. 

• The protocol update (2023) (available in Dutch and in French)  now includes an aggregated denominator data registration option which reduces the registration burden. An optional evaluation of perioperative antibiotic prophylaxis administration was also added. A complete overview of the changes from the previous version can be found in section 1.3 Modifications. 
• Data collection and reporting migrates to the Healthdata platform in 2024.

The protocol (2023) includes the following annexes:

• Data definition and registration instructions (available in Dutch and in  French)
• Forms (available in  Dutch and in  French) for paper-based registration
• ICD-10-PCS code list (available in  Dutch and in  French) including description per code per operation category
• Sample registration forms for surveillance post discharge for consultation with the general practitioner (available in Dutch and in   French) and with the surgeon (available in  Dutch and in French). These forms can be adapted based on local organization of surveillance and hospital needs.