Natalie Blencowe and Jane Blazeby: Core outcomes for surgical procedures

comet “Emergency surgery patients must have higher priority in NHS hospitals.” So say the new standards from the Royal College of Surgeons of England, which highlight the wide range of complication rates following emergency surgery across the NHS. Interpreting these data is not straightforward, not least because there are no accepted standards for measuring or defining surgical complications. For example, a “wound infection” in one centre may be “minor inflammation” in another. Even definitions of death rates following surgery can vary, making comparisons of something that might seem clear cut, difficult. The use of different terms and definitions for complications after surgical procedures makes comparing outcomes between hospitals problematic. How does one know if the hospitals are truly different in their complications, or just in their ways of counting or labeling them?

One area of surgery that has successfully pioneered routine and well defined outcome reporting is cardiothoracic surgery.  A single measure of “operative mortality” has been agreed and is routinely measured and reported for all patients undergoing coronary artery bypass grafting (CABG). This allows summary statistics and cross-centre comparisons to be made. But despite this step forward, other outcomes of cardiac surgery such as complications and long term impact on quality of life are less well defined, measured, and reported. This limits full evaluation of the effects of the procedure.

Similar problems have been reported after reconstructive breast surgery following mastectomy for cancer. A recently published review summarizing these outcomes, identified 950 potential different complications, but fewer than 20% of these were defined, and definitions were largely inconsistent.

A core outcome set for each surgical condition would help to solve these problems, as long as it also has agreed definitions for each outcome. Such sets would contain a mandatory set of outcomes to be measured and reported as a minimum for patients undergoing a particular procedure. This idea has developed from clinical trials, where core outcome sets are being proposed to improve data synthesis and reduce problems with outcome reporting bias. The COMET (Core Outcome Measurement in Effectiveness Trials) initiative aims to facilitate this in all areas of healthcare, bringing together researchers interested in the development and application of core outcome sets.

We are currently developing core outcome sets for oesophageal and colorectal cancer surgery, and for obesity surgery. A core outcome set may also be beneficial in clinical practice, because these data could be provided as a minimum for patients who are due to have a particular operation – perhaps as a “core disclosure set” – within the information they are given. Returning to emergency surgery, however, although core outcome measures have not yet been identified, they might include things such as in-hospital death or wound infection. 

COMET’s second international conference will be in Bristol on July 11th-12th. This will provide opportunities for discussion, collaboration and generation of further disease-specific core outcome sets. You can register via the website.

Jane Blazeby is a professor of surgery and honorary consultant surgeon who also directs the MRC ConDuCT Hub for trials methodology research. Natalie Blencowe is an academic clinical fellow in general surgery.