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Telling the Whole Story: Measuring Patient Outcomes with Composite Length of Stay

After surgery, all patients hope for a fast and full recovery. Surgeons can help reassure patients of these outcomes by studying the results of past procedures. Procedures with short recovery times might be appealing to patients hoping to get back to their lives without delay, but according to a recent study led by the Department of Surgery at Washington University School of Medicine in St. Louis, in some cases it may be beneficial to stay in the hospital a little longer to monitor complications and ensure the most successful outcome.

The study, published in the Journal of Gastrointestinal Surgery (JOGS) in December, examines results from nearly 700 patient cases to better understand how hospital length of stay relates to the success of a procedure. Washington University School of Medicine surgeons worked alongside researchers and statisticians to analyze a wealth of data from these patient cases. William C. Chapman, MD, William G. Hawkins, MD, Ryan C. Fields, MD, Majella B. Doyle, MD, MBA, Chet W. Hammill, MD, MCR, Adeel S. Khan, MD, MPH, and Steven M. Strasberg, MD, from the Division of General Surgery, represented the medical school in this study.

One way of gauging the success of a procedure is by measuring postoperative length of stay (PLOS). PLOS refers to the number of days patients spend in the hospital after operations. A shorter PLOS suggests that the patient recovered quickly, because they spent fewer days in the hospital following surgery. Readmission rate is another way of measuring the quality of care after an operation, since fewer readmissions means the patient did not have to return to the hospital for further treatment.

Strasberg, the Pruett Professor of Surgery, sees PLOS and readmission rates as parts of a larger story. Looking at these metrics individually tells him something about a patient, but it does not give him a full understanding of a patient’s time in the hospital. In the JOGS study, Strasberg and team evaluate a new measurement for understanding surgical outcomes: composite length of stay (CLOS).

CLOS is the combination of PLOS and all readmissions—in other words, this is a single measurement that accounts for all of a patient’s time in the hospital. With this metric, Strasberg believes surgeons have a more complete story of a patient’s postoperative outcome.

Clinical Expertise Meets Research Excellence

Strasberg is a hepatobiliary-pancreatic and gastrointestinal surgeon in the Division of General Surgery. As a specialist in pancreas, liver and gallbladder surgery, Strasberg has performed many major operations, including some that inherently involve risks of serious complications. One of these operations is the Pancreatoduodenectomy, more commonly referred to as the Whipple procedure.

Whipple procedures are complex, involving the removal of parts of the pancreas, small intestine, bile duct and gallbladder, and are typically used as treatment for pancreatic cancer. Despite the complexity of this and other hepatobiliary procedures, Strasberg has been focused on this area of surgery for over 50 years.

As a resident at University of Toronto, Strasberg became very interested in studying the liver. He was seeing things in patients that had not yet been studied in depth, which piqued his curiosity. Strasberg began conducting focused research in an area that was ripe for discovery.

“There was no specialty in surgery of the liver, pancreas and biliatry,” Strasberg recalls. Rather than seeing this as a problem, Strasberg saw an opportunity. He spent two years researching in Boston, then returned to Toronto, where he took as many cases as he could in this particular area and set up a lab of his own. With this wealth of knowledge and experience, Strasberg then came to Washington University, where he has practiced and researched in the Department of Surgery ever since.

When Strasberg is not in the operating room, he is furthering hepatobiliary research through his writing. “I like to write, and to connect with other surgeons,” Strasberg says. His prolific publication history certainly reflects that passion: Strasberg has published papers on hepatic arterial infusion, pancreatic resection and laparoscopic cholecystectomy—and those are just a few of his publications from the past year. Recently, he has turned his attention to CLOS after Whipple procedures.

Outside of the operating room, Strasberg contributes to research through his writing and conferences with other surgeons.

Following Through on Quality Care

Between August 2011 and July 2018, a total of 668 patients had Whipple procedures at the School of Medicine. The team of School of Medicine surgeons used data from these procedures to compare CLOS with the usual ways of measuring patient care. Strasberg suspected that PLOS was not telling the whole story, and that he could learn something by examining readmissions more closely.

Of the 668 patients receiving Whipple procedures, 432 developed postoperative complications. These complications led to 177 patients being readmitted. Previous studies have documented that readmissions are common after the Whipple procedure, which is one reason it was chosen for this study. With nearly 27% of patients requiring readmission, it was clear that PLOS alone was not an accurate representation of a patient’s time in the hospital. Looking at readmissions would prove to be another important part of truly delivering the best quality care.

There are some challenges to measuring readmission. First, readmissions are recorded as “events” rather than numbers of days, meaning that the amount of days a patient is readmitted is not accounted for. Second, some patients do not return to the home hospital when readmitted, making it difficult to track their treatment beyond PLOS. The third hurdle is that not all readmissions are of the same severity, which makes comparing readmissions more complex.

For this study, the researchers tracked the length of readmissions rather than recording them as events. This helped show the difference between a short, overnight readmission and one that was longer and more severe. To account for time at other hospitals, they conducted follow-ups with patients after 90 days.

Measuring the severity of complications was the final piece of this puzzle. The team decided to use the Modified Accordion Grading System (MAGS) to categorize complications. MAGS is a sliding scale that helps surgeons define a complication’s severity based on the treatment it required. With MAGS and the rest of their methods in place, the team was able to draw conclusions based on a patient’s PLOS, how soon that patient was readmitted and the severity of their complications.

The Best, Most Accurate Measure of Outcome

These measurements help surgeons and patients think about what actually happens after a procedure. The ideal outcome will always be zero complications and no readmissions. For many patients recovering from major operations like Whipple procedures, however, complications may be more probable. Knowing the likelihood of these complications, and when they might arise, helps ensure the best possible outcome.

“We help patients by understanding what our outcomes are,” Strasberg says, emphasizing the importance of developing an accurate metric for recording length of stay.

Some patients returned to the hospital after complications classified as mild or moderate on the MAGS scale, while others had severe complications. Mild and moderate complications, such as gastrointestinal disorders and surgical site infections, could be treated with drugs or minor invasive procedures. More severe complications can require general anesthesia and reoperation.

For patients experiencing mild and moderate complications, readmission often shortly followed the initial PLOS. In these cases, there may have been a chance to treat or even prevent the complications if the patient had a longer initial PLOS. Staying in the hospital an extra day or two might not sound ideal, but for certain patients and procedures it could be the best way to avoid readmission.

The more severe the complication, the longer a patient’s readmission. The longer a readmission, the greater the difference between PLOS and CLOS. This means that procedures said to have short PLOS might actually have a longer overall stay if readmissions were taken into account.

The findings of this study from the School of Medicine suggest that CLOS might be a better, more relevant way of measuring patient outcomes after surgery, despite the difficulties involved in tracking complications and readmissions.

Composite Length of Stay (CLOS) helps Strasberg more precisely measure patient outcomes.

An Evolving Interest

Strasberg’s specialty has always been in hepatobiliary-pancreatic surgery, but his interests have grown over a long, successful career. The lab Strasberg started in Toronto was studying how bile was formed in the liver. Since then, Strasberg has performed a host of operations, mentored other surgeons and helped countless patients.

Why turn his attention to length of stay?

“I have an interest in frailty,” Strasberg says. “In French, frailty is fragilité.”

Strasberg sees patients from all walks of life. While not all of his patients are advanced in age, he is particularly concerned with the needs of fragile patient populations.

Recovery, and the ability to perform the tasks of daily living, are especially sensitive matters for these patients, and Strasberg hopes to improve our understanding of how length of stay fits into this larger story of patient care in order to help fragile patient populations thrive.