Infection and Mortality in Hip Arthroplasty Patients
Infection and Mortality in Hip Arthroplasty Patients
A review of Medicare claims has identified specific patient comorbidities associated with an increased risk for periprosthetic joint infection and 90-day postoperative mortality in patients who underwent total hip arthroplasty, according to results published in The Journal of Bone and Joint Surgery.
"Total hip arthroplasty is one of the most common procedures performed in the United States and is most commonly performed on Medicare patients," lead author Kevin Bozic, MD, MBA, Associate Professor and Vice Chair in the Department of Orthopaedic Surgery at the University of California, San Francisco Medical Center told Medscape. "The vast majority of these procedures are successful in improving patients' quality of life and function, reducing their pain, and restoring them to an active lifestyle."
However, there are catastrophic complications, including infection and death, that can occur. Although clinical risk-stratification systems are used by physicians, none have been validated in patients undergoing total hip arthroplasty. Dr. Bozic and colleagues used the Medicare 5% claims database to calculate the risk for periprosthetic joint infection and 90-day postoperative mortality among patients undergoing total hip arthroplasty.
A review of ICD-9 code (27130) claims across the database yielded 40,919 patients who underwent total hip arthroplasty between 1998 and 2007. Inpatient and outpatient claims were analyzed to assess comorbidities in the 12 months prior to hip arthroplasty. Patients younger than 65 were excluded from the data set.
"Our goal was to identify patients' specific risks to enable a more informed discussion between the surgeon and the patient regarding their individual risk," Dr. Bozic said.
The team examined the impact of 29 comorbid conditions on periprosthetic joint infection and on postoperative mortality using a multivariate Cox regression, controlling for age, sex, race, census region, and public assistance. They then calculated crude relative risk and adjusted hazard ratio (HR) for each comorbid condition. The resulting P value for the HR was used to rank the degree of association of each comorbid condition with death and periprosthetic joint infection.
The authors noted that postoperative infection and mortality are complex events that involve multiple factors, and many other potential factors that may contribute to these outcomes could not be captured by using only the comorbid conditions considered in their analysis.
The researchers found that the top 4 comorbid conditions that put patients at risk for periprosthetic hip infection were:
The top 5 comorbid conditions for 90-day postoperative mortality identified by the researchers were:
Overall, 98% of hip arthroplasty patients survived beyond the 90-day threshold in the study. In addition, 98.37% of patients remained free of periprosthetic hip infection after 1 year.
Limitations of the study identified by the authors include its reliance on administrative claims data, which may not correlate exactly with the clinical record. They did note that this limitation was mitigated by the large sample size and that the prevalences of their selected comorbid conditions were similar to those reported in other population-based studies of hip arthroplasty patients.
"This study is unique in that it uses a large Medicare database to look across the board at many complications and identifies some that have particular concern, either in terms of predicting infection or in terms of perioperative mortality," William Robb, III, MD, Chair of the Patient Safety Committee of the American Academy of Orthopedic Surgeons told Medscape.
"The good news is that this study supports many of the risk factors that physicians understand and, frankly, most patients understand as well," he said. "It reinforces, for both physicians and patients, that where those risk factors exist that informed consent has to focus on those factors so patients understand the risk they're taking and physicians can better manage the preoperative and perioperative course."
The study was funded by the Mayo Clinic; the University of California, San Francisco; and Massachusetts General Hospital. The funding sources did not play a role in the investigation. Dr. Bozic has served as a consultant to United Healthcare, the Blue Cross Blue Shield Association, Integrated Healthcare Association, Pacific Business Group on Health, Centers for Medicare & Medicaid Services, and Ingenix.
A review of Medicare claims has identified specific patient comorbidities associated with an increased risk for periprosthetic joint infection and 90-day postoperative mortality in patients who underwent total hip arthroplasty, according to results published in The Journal of Bone and Joint Surgery.
"Total hip arthroplasty is one of the most common procedures performed in the United States and is most commonly performed on Medicare patients," lead author Kevin Bozic, MD, MBA, Associate Professor and Vice Chair in the Department of Orthopaedic Surgery at the University of California, San Francisco Medical Center told Medscape. "The vast majority of these procedures are successful in improving patients' quality of life and function, reducing their pain, and restoring them to an active lifestyle."
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Kevin Bozic, MD, MBA |
However, there are catastrophic complications, including infection and death, that can occur. Although clinical risk-stratification systems are used by physicians, none have been validated in patients undergoing total hip arthroplasty. Dr. Bozic and colleagues used the Medicare 5% claims database to calculate the risk for periprosthetic joint infection and 90-day postoperative mortality among patients undergoing total hip arthroplasty.
A review of ICD-9 code (27130) claims across the database yielded 40,919 patients who underwent total hip arthroplasty between 1998 and 2007. Inpatient and outpatient claims were analyzed to assess comorbidities in the 12 months prior to hip arthroplasty. Patients younger than 65 were excluded from the data set.
"Our goal was to identify patients' specific risks to enable a more informed discussion between the surgeon and the patient regarding their individual risk," Dr. Bozic said.
The team examined the impact of 29 comorbid conditions on periprosthetic joint infection and on postoperative mortality using a multivariate Cox regression, controlling for age, sex, race, census region, and public assistance. They then calculated crude relative risk and adjusted hazard ratio (HR) for each comorbid condition. The resulting P value for the HR was used to rank the degree of association of each comorbid condition with death and periprosthetic joint infection.
The authors noted that postoperative infection and mortality are complex events that involve multiple factors, and many other potential factors that may contribute to these outcomes could not be captured by using only the comorbid conditions considered in their analysis.
The researchers found that the top 4 comorbid conditions that put patients at risk for periprosthetic hip infection were:
Rheumatologic disease (adjusted HR = 1.71; 95% confidence interval [CI], 1.42-2.06, P < .0001);
Obesity (HR = 1.73; 95% CI, 1.35-2.22, P = .0014);
Coagulopathy (HR = 1.58; 95% CI, 1.24-2.01, P = .0188); and
Preoperative anemia (HR = 1.36; 95% CI, 1.15-1.62, P = .0347).
The top 5 comorbid conditions for 90-day postoperative mortality identified by the researchers were:
Congestive heart failure (HR = 2.11; 95% CI, 1.76-2.52, P < .0001);
Metastatic cancer (HR = 3.14; 95% CI, 2.27-4.34, P < .0001);
Psychosis (HR = 1.85; 95% CI, 1.47-2.32, P < .0001);
Renal disease (HR = 1.98; 95% CI, 1.53-2.57, P < .0001); and
Dementia (HR = 2.04; 95% CI, 1.55-2.69, P < .0001).
Overall, 98% of hip arthroplasty patients survived beyond the 90-day threshold in the study. In addition, 98.37% of patients remained free of periprosthetic hip infection after 1 year.
Limitations of the study identified by the authors include its reliance on administrative claims data, which may not correlate exactly with the clinical record. They did note that this limitation was mitigated by the large sample size and that the prevalences of their selected comorbid conditions were similar to those reported in other population-based studies of hip arthroplasty patients.
"This study is unique in that it uses a large Medicare database to look across the board at many complications and identifies some that have particular concern, either in terms of predicting infection or in terms of perioperative mortality," William Robb, III, MD, Chair of the Patient Safety Committee of the American Academy of Orthopedic Surgeons told Medscape.
"The good news is that this study supports many of the risk factors that physicians understand and, frankly, most patients understand as well," he said. "It reinforces, for both physicians and patients, that where those risk factors exist that informed consent has to focus on those factors so patients understand the risk they're taking and physicians can better manage the preoperative and perioperative course."
The study was funded by the Mayo Clinic; the University of California, San Francisco; and Massachusetts General Hospital. The funding sources did not play a role in the investigation. Dr. Bozic has served as a consultant to United Healthcare, the Blue Cross Blue Shield Association, Integrated Healthcare Association, Pacific Business Group on Health, Centers for Medicare & Medicaid Services, and Ingenix.
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