Young age and male gender cited as risk factors for in-hospital SSI after THA, TKA

Issue: September 2012

A recently presented study identified age, gender and racial minority status as risk factors for perioperative surgical site infection following total hip and knee arthroplasty.

"Our regression model revealed that patient-related factors such as age younger than 44 years, male gender and [racial] minority were associated with the highest odds of [surgical site infections]," Lazaros A. Poultsides, MD, PhD, said during his presentation at the American Academy of Orthopaedic Surgeons 2012 Annual Meeting. "Interestingly, obesity and uncomplicated diabetes, at least for the perioperative setting, were not found to be associated with the highest odds."

In-hospital data

Poultsides and his group analyzed national inpatient sample hospitalization data for total hip arthroplasties (THAs) and total knee arthroplasties (TKAs) between 1998 and 2007. They found 412,356 patient entries for THA and 784,335 entries for TKA. The investigators compared the demographics, morbidity, mortality, length of hospitalization, comorbidities and overall in-hospital costs between patients who sustained perioperative surgical site infections (SSIs) and those who did not.

"Patients who develop [SSIs] experience a higher incidence of procedure-related complications, specifically cardiac, respiratory and gastrointestinal," Poultsides said. "The rate of blood transfusion was double for infected patients, while the length of hospital stay was almost three times more."

Poultsides reported perioperative SSI rates of 0.36% for THA and 0.31% for TKA. Comorbidity burdens were higher among patients who experienced SSIs. This, Poultsides noted, was reflected in significantly higher rates of chronic pulmonary disease, alcoholism, congestive heart failure, cancer and complicated diabetes. Patients who sustained SSIs also had higher mortality rates (2.5% vs. 0.3% in the THA group and 1.2% vs. 0.1% for TKA group) and longer average hospital stays.

Poultsides added deep vein thrombosis, pulmonary embolism, surgical site hematoma and acute respiratory distress syndrome were more frequently found in patients who sustained SSIs.

Higher odds

Compared to a referent group of patients aged 45 years to 64 years, patients aged 44 years or younger had 1.7 times higher odds of having an SSI. Compared to the referent group, patients aged 65 years to 74 years had a 0.9 times higher odds, and those 75 years or older had a 0.98 times higher odds.

The investigators also found that men had a 1.33 times higher odds for SSIs than women. Compared to white patients, black, hispanic and other minority patients had odds ratios of 1.39, 1.50 and 1.48, respectively.

"Perioperative [SSIs] following hip and knee arthroplasty are associated with increased morbidity and mortality, length of stay and increased in-hospital cost," he said. "Comorbidities subjecting patients to an immuno-compromised state or predisposing them to hematoma formation were associated with highest odds for [SSIs]. Our future goals are to identify potential patients who present with an elevated risk of infection and to designate appropriate interventions in order to reduce infections and complications in these high-risk population groups." – by Robert Press

Reference:

Poultsides LA, Ma Y, Gonzalez Della Valle A, et al. In-hospital surgical site infections after primary hip and total knee arthroplasty — Incidence and risk factors. Paper 42. Presented at the American Academy of Orthopaedic Surgeons 2012 Annual Meeting. Feb. 7-11. San Francisco.

For more information:

Lazaros A. Poultsides, MD, PhD,can be reached at Hospital for Special Surgery, 535 E. 70th St., New York, NY 10021; email: poultsidesl@hss.edu.
Disclosure: Poultsides has no relevant financial disclosures.