Baseline CT findings can serve as independent predictors of clinical outcomes, hospital resource utilization, and inpatient costs in cases related to acute appendicitis, according to a recent study published in the American Journal of Roentgenology.

Andrew B. Rosenkrantz, MD, and colleagues from the NYU Langone Medical Center department of radiology conducted the study by examining the CT scan data of 138 patients admitted for suspected acute appendicitis.

As the authors explained, being able to understand the cause and effect in healthcare is especially important with the increased focus on quality over quantity.

“Given the ongoing restructuring of health care payment systems to promote greater value and efficiency of care, such insights may be useful to support efforts at the overall practice level to manage costs and additional hospital resource utilization for this condition,” the authors wrote.

Inpatient surgery and complicated appendicitis

Of the 138 patients, a total of 97 (70.3 percent) underwent inpatient surgery. Surgery was performed on the same day as CT in 53 of those 97 cases, and on the following day in another 38. In addition, a laparoscopic approach was used for for 89 (91.8 percent) of the surgeries and the others were open.

The authors’ multivariable analysis showed that independent predictors of inpatient surgery included: greater age, lower Charlson comorbidity index (CCI), smaller appendiceal wall thickness, absence of loculated right lower quadrant (RLQ) fluid, and the absence of periappendiceal free fluid.

Together, the sensitivity of these predictors was over 92 percent and the specificity was over 65 percent.

In addition to those 97 patients who underwent inpatient surgery, another 22 patients had surgery for appendicitis after discharge. Of those 116 total patients who underwent surgery, 66 (56.9 percent) showed signs of complicated appendicitis.

Again looking at the authors’ multivariable analysis, independent predictors of complicated appendicitis included the presence of an appendicolith and greater appendiceal diameter. Together, the sensitivity of these predictors was greater than 64 percent and the specificity was greater than 75 percent.

Hospital resource utilization

A total of 67 patients (48.6 percent) were discharged on the day of admission. The multivariable analysis showed that independent predictors of discharge on the day of admission included smaller appendiceal diameter, absence of periappendiceal free fluid and undergoing laparoscopic surgery.

Together, the sensitivity of these predictors was over 79 percent and the specificity was over 64 percent.

Thirteen of the 138 patients (9.4 percent) experienced abdominal pain within 30 days of being discharged and had a subsequent visit to the emergency department. The one significant predictor of that additional visit was the presence of an appendicolith, with a sensitivity of over 63 percent and specialty of over 68 percent.

Total inpatient costs

The average total inpatient costs was more than $19,000, ranging from approximately $3,600 to more than $90,000.

According to the multivariable analysis, greater appendiceal diameter and the presence of free air were the most significant predictors of inpatient costs, but those two factors failed to predict the costs for patients with costs greater than $45,000.

“There are additional factors not included in our model that influenced total costs, particularly for the highest-cost admissions,” the authors wrote. “A more detailed and targeted assessment of these highest-cost cases is therefore warranted to better understand the factors contributing to their increased costs and thereby guide future efforts to avoid markedly elevated inpatient costs for some patients with acute appendicitis.”