Pulmonary Embolism Higher at Low Volume Hospitals

Patients who underwent elective total hip (THA) or total knee arthroplasty (TKA) surgeries in low-volume hospitals had a higher risk of venous thromboembolism and mortality following the procedure, a recent study suggests.

For the study, researchers sought to examine the relationship between hospital surgical volume and postoperative complications. They assessed the 30-day complication rate and 30 day and one-year mortality rates in a group of 29,000 patients undergoing elective either THA or TKA in 2002 from data from the Pennsylvania Health Care Cost Containment Council database. The mean age of patients in both groups was 69 years.

Hospitals were categorized according to their annual volume of THA/TKA procedures as very low volume, low volume, high volume or very high volume.

The researchers found that patients who had primary THA at low-volume hospitals were more likely to develop a pulmonary embolism within 30 days of surgery than those who had surgery at a high-volume hospital. The one-year mortality also was higher for patients having THA at low-volume hospitals. They found that for TKA, lower hospital volume was also associated with a higher risk of one-year mortality for patients 65 and older.

The researchers wrote in the study that further research is needed “to examine whether the type and duration of the thromboprophylactic agent/device being used in the low-volume hospitals are associated with this increased risk of venous thromboembolism.”

“Venous thromboembolism is a preventable complication following elective THA and TKA. There is an intense ongoing debate regarding the best choice of medication/devices for venous thromboembolism prophylaxis in patients undergoing THA and TKA. The risk of venous thromboembolism is most likely impacted not only by the choice of thromboprophylactic agent/device, but also by the time of initiation and cessation of such therapy.”

Lead author Jasvinder Singh, MD, MPH, of the VA Medical Center and University of Alabama both in Birmingham, told U.S. Medicine that one finding that surprised him was the higher mortality at one year for the THA patients and the TKA patient older than 65.

“We tend to think that the impact of immediate complications is immediate mortality. So to see that even after adjusting for the patients’ own risk of mortality that we saw adverse mortality outcomes for up to a year tells us something that we don’t typically think about in patients undergoing elective joint replacement,” he said. “That result was surprising and is worth further study.”

Singh and his colleagues concluded that “future studies should focus on investigating whether the underlying reasons for suboptimal outcomes at low volume hospitals are modifiable (i.e., system factors, perioperative and postoperative care algorithms).

The study pointed out that previous research has linked surgical outcomes with the surgery volume for a variety of procedures. The researchers cited a study of 90-day complication rates in 80,904 Medicare patients who underwent primary TKA, adjusting the analyses for age, sex, Medicaid eligibility, comorbidities, and underlying diagnosis. They said that study reported that the risk of pneumonia was significantly higher among patients for whom joint replacements were performed in “low-volume” hospitals.

That study differed from the one done by Singh and his team in that that Singh’s included individuals who underwent the procedures regardless of age, and was not limited to Medicare patients. Singh said he and his colleagues were also able to adjust for the risk of overall surgical mortality using the APR-DRG score for the risk of mortality, whereas the other study did not.

“Hospital Volume and Surgical Outcomes after Elective Hip/Knee Arthroplasty: A Risk Adjusted Analysis of a Large Regional Database.” Jasvinder A. Singh, C. Kent Kwoh, Robert M. Boudreau, Gwo-Chin Lee, Said A. Ibrahim. Arthritis & Rheumatism; Published Online: June 7, 2011 (DOI: 10.1002/art.30390).

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