Better clinical pathways needed for adults with suspected appendicitis

Last Updated: 2019-12-16

By Will Boggs MD

NEW YORK (Reuters Health) - One in five appendectomies in the U.K. remove a normal appendix, but consistent use of appendicitis risk-prediction models could significantly reduce this rate, according to a new review.

"We have found that simple risk scores can help stratify a group of patients at low risk of appendicitis," Dr. Dmitri Nepogodiev of the University of Birmingham told Reuters Health by email. "Many of these patients can be discharged with the option of next-day clinic follow-up, perhaps for an ultrasound scan to exclude gynecological pathology."

The symptoms of acute appendicitis, particularly in women, are shared by various other lower abdominal conditions. International guidelines recommend routine clinical risk scoring to improve the diagnosis and to reduce normal appendectomies.

Dr. Nepogodiev and colleagues in the Right Iliac Fossa Treatment (RIFT) Study Group sought to identify the optimal risk prediction model to identify young adults (aged 16-45 years) in the U.K. at low risk of acute appendicitis.

Based on data from the U.K., Italy, Portugal, the Republic of Ireland and Spain, the rate of removing a normal appendix (normal appendectomy rate, or NAR) was 20.0% in the U.K. versus 6.2% in the other countries. In the U.K., the NAR was more than twice as high in women (28.2%) as it was in men (12.1%).

Although two-thirds of the U.K. patients with suspected appendicitis included in the study were women, women were only about half as likely as men to undergo any surgery (32.0% vs. 59.8%, respectively).

Women were also only about a third as likely as men to have a confirmed diagnosis of appendicitis (17.3% vs. 48.6%, respectively).

Overall, only 0.6% of patients with suspected appendicitis were recorded as having been formally risk-scored on admission by their clinical team, the researchers report in BJS.

Of the 15 risk-prediction models evaluated by the study group, the Adult Appendicitis Score achieved the highest specificity (63.1%) while maintaining a failure rate of only 3.7% among women, while the Appendicitis Inflammatory Response Score performed best overall among men (with 24.7% specificity and a 2.4% failure rate).

Nine other risk-prediction models showed consistently good discrimination for identifying appendicitis (i.e., AUC above 70%) across both women and men.

"We suggest that all patients with suspected appendicitis should routinely be risk scored, using the Adult Appendicitis Score in women and the Appendicitis Inflammatory Response Score in men, Dr. Nepogodiev said.

"We have created a mobile-friendly website to support risk scoring: http://appy-risk.org. However, it's important to remember that whilst risk scores can inform decision making, they do not replace clinical judgment, and some low-risk patients will require admission for inpatient investigation and treatment," he added.

"By scaling our findings up across the U.K., we estimate that there are 53,000 potentially avoidable hospital admissions and 5,500 potentially unnecessary appendicectomies each year in adults aged 16-45 years," he said. "The appendicectomies alone cost the National Health Service 13.7 million. We believe this is an important area for further research, for example, to evaluate the impact and safety of changing practice to implement the recommendations made in our study."

Dr. Jon Gani, a conjoint professor of surgery at the University of Newcastle, in Australia, told Reuters Health by email that the new findings "should encourage the routine use of the correct risk-assessment tool in the U.K. as this may result in more ambulatory treatments for RIF pain and fewer hospital admissions."

"The difference in presentation rates and rates of appendicitis amongst non-U.K. RIF pain patients remains unexplained, and it is unclear whether this represents a difference in the disease process or in the access to the hospital-based model of care," he said. "However, the use of the risk-assessment tools in these population groups (non-U.K.) is not validated."

SOURCE: https://bit.ly/34g4lEp BJS, online December 3, 2019.