Brief fitness questionnaire beats ‘gold standards’ as predictor of surgical risk
The gold standard assessments health-care practitioners use to predict risk of morbidity and mortality after surgery are not the most accurate indicators, suggests an international study published in The Lancet. Instead, a brief questionnaire known as the Duke Activity Status Index (DASI) beats more expensive, time-consuming testing.
Researchers followed 1,500 patients across 25 centres in Canada, Australia, New Zealand and the United Kingdom. They compared four commonly used tests that aim to assess a patient’s heart and lung fitness (known as functional capacity) before intermediate or major surgery to understand which test was the most predictive of various outcomes after surgery: DASI, cardiac pulmonary exercise test (CPET), blood test, and subjective clinical assessment by experienced anaesthesiologists.
“The most sophisticated, highly technological test – CPET – that we thought would be the best, and has been touted as the gold standard, was effectively the least good at predicting key patient outcomes,” says Dr. Brian Cuthbertson, Chief, Department of Critical Care Medicine at Sunnybrook Health Sciences Centre, chief international investigator and co-author of the study along with anaesthesiologist Dr. Duminda Wijeysundera of University Health Network and St. Michael’s in Toronto.
Similar to the traditional stress test, the CPET measures a person’s oxygen consumption while exercising on a treadmill or stationary bike.
“[CPET] predicted complications of surgery, but it didn’t actually predict the arguably more serious post-operative outcomes like death or heart attack,” adds Dr. Cuthbertson.
Also ranked poorly was the subjective clinical assessment, followed by the blood marker called BNP that, although the study suggests is better than some of these measures, is not good enough to be used in clinical practice, according to the authors.
Ranked the most effective, DASI is a 12-item fitness questionnaire that asks whether or not a patient is able to walk indoors, climb a flight of stairs, run a short distance, do yardwork, participate in strenuous sports and other recreational or daily living activities. Answers are weighted and the higher the score, the higher the functional status.
Dr. Cuthbertson says these findings are also the first step to truly reducing cardiac risk and mortality for people undergoing surgery: “Now that we can more accurately identify who is at risk, we can look at what can be done to intervene and prevent negative outcomes after surgery for our patients.”
