Patients who have an infection within 30 days of surgery appear to be at higher risks of subsequent infections and mortality for up to 1 year, according to a study.
Throughout the United States, significant resources are being used to prevent postoperative infections due to their potentially serious consequences. “Much attention has been given to the identification, prevention, and management of postoperative infections, typically within 30 days of surgery or up to 90 days for surgical implants,” explains William J. O’Brien, MS. “In the short term, these infections can be devastating for patients in terms of pain, need for reoperation and rehospitalization, and exposure to long-term antibiotics. However, little is known if patients exposed to infection after surgery have higher rates of subsequent infections and mortality within 1 year.”
For a study published in JAMA Surgery, O’Brien collaborated with Kalpana Gupta, MD, and Kamal M.F. Itani, MD, to determine if exposure to 30-day postoperative infections was associated with a higher incidence of infection and mortality up to 1 year after surgery. Using data from the Veterans Affairs (VA) national database, the study included more than 650,000 veterans who underwent a broad range of major surgery types during an 8-year period. The exposure group included VA patients who had any 30-day postoperative infection while the control group consisted of VA patients who had no 30-day infection.
According to investigators, 3.6% of all participants in the study had a 30-day infection, 6.6% had a long-term infection, and 3.8% died during follow-up. Overall, the incidence of infection during postoperative days 31 to 365 was 6.7%. The most frequent 30-day infections were surgical site infections, urinary tract infections, pneumonia; and bloodstream infections. The most frequent types of infections on postoperative days 31 to 365 were urinary tract infections, skin and soft tissue infections, bloodstream infections, pneumonia, or a combination of 2 or 3 types simultaneously (Figure).
“Our key findings were that patients with a 30-day postoperative infection were at nearly twice the risk of mortality and had more than three times the risk of subsequent infection when compared with patients without such an infection,” says O’Brien. When compared with patients who had no postoperative infections, those with these infections tended to be older and more frequently had an American Society of Anesthesiologists score greater than 2. The study also found that patients with any postoperative infection were more likely to have undergone emergent surgery and to have undergone surgery with a duration in the highest quartile when compared with patients who had no postoperative infections.
Findings of the study persisted after adjusting for baseline characteristics. Although few published studies have examined rates of long-term infection, results from the current study were comparable to that of previous work that sought to describe mortality risks.
Efforts to prevent postoperative infections continue to be a high priority in clinical practice and across healthcare settings because of their significant impact on costs, patient outcomes, and resource utilization. The novel contribution of the study by O’Brien and colleagues is that the occurrence of a postoperative infection—regardless of patient characteristics and surgery factors—appears to be associated with a higher likelihood of having a subsequent infection and mortality up to 1 year after the initial surgery.
“Our study demonstrated that postoperative infections in the overall surgical population were relatively uncommon but associated with long-term harm to patients,” O’Brien says. “Our study wasn’t intended to directly influence surgical practice. Instead, our goal was to better understand the long-term risks of surgical infections. Future work in this area could help us appreciate the extent to which the long-term consequences described in our study are directly related to the postoperative infections.” The study team added that the increased harm and cost of long-term infections should be included in cost-benefit calculations of infection prevention initiatives.