Standardised Definition of Morbidity in Clinical Trials

Clavien-Dindo Classification


Minor Morbidity (Grade 1 according to the Clavien-Dindo classification)


Any deviation from the normal postoperative course without the need for pharmacological treatment or surgical, endoscopic and radiological interventions. Allowed therapeutic regimens are: drugs as antiemetics, antipyretics, analgetics, diuretics and electrolytes and physiotherapy. This grade also includes wound infections opened at the bedside.



Major morbidity (Grade 2 to 4 according to the Clavien-Dindo classification)


Grade 2: Requiring pharmacological treatment with drugs other than such allowed for grade I complications. Blood transfusions and total parenteral nutrition are also included.


Grade 3: Requiring surgical, endoscopic or radiological intervention.


Grade 3a: Intervention not under general anaesthesia


Grade 3b: Intervention under general anaesthesia


Grade 4: Life-threatening complication (including CNS complications) requiring Intermediate care/ICU-management


Grade 4a: Single organ dysfunction (including dialysis)


Grade 4b: Multiple organ dysfunction (including dialysis)


Grade 5: Death of a patient





If more than 1 complications are present the highest grade of complication should be used for statistical purposes



The total number of complications may be a useful numeric parameter when predicting outcomes



If the patients suffers from a complication at the time of discharge, the suffix “d” (for ‘disability’) is added to the respective grade of complication. This label indicates the need for a follow-up to fully evaluate the complication.




Latest News

Follow us

Recommend this page on:

Contact us

Email us at:


You can also use our contact form.



Links to third party web sites are provided here. The School of Surgery Editors have reviewed all of these third party sites, but we neither control nor are responsible for any of the content. The views expressed in the links may not reflect the views or the practice of the Editors. Some users may find the content disturbing as it shows detailed surgical procedures. If you access any of the third party sites linked to this site you do so entirely at your own risk. In addition, the Editors strictly comply with the GMC's Policy on Social Media.