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American College of Rheumatology (ACR): Winter Rheumatology Symposium
Expert calls pegloticase a powerhouse gout drug not to be feared
SNOWMASS, COLO. – Pegloticase (Krystexxa) is a gout drug that’s expensive, inconveniently administered by intravenous infusion every 2 weeks, and saddled with a substantial rate of immunogenicity, with infusion reactions that can include anaphylaxis.
So why does gout authority Dr. Michael H. Pillinger call pegloticase "a greatly underestimated and underutilized drug"? And why do the current American College of Rheumatology gout guidelines recommend pegloticase for refractory gout?
"Nothing else we have will get rid of tophi the way this drug gets rid of tophi," Dr. Pillinger explained at the Winter Rheumatology Symposium sponsored by the American College of Rheumatology.
"Why do we care about that? Because tophi are erosive, they’re damaging, and also because they’re much more extensive than we think they are," said Dr. Pillinger, a rheumatologist and director of the crystal diseases study group at New York University.
Besides, the safety concern regarding this powerhouse urate-lowering drug has been resolved. The infusion reactions are readily avoidable. Pegloticase is not a drug rheumatologists should be scared of, he emphasized.
Dr. Pillinger cited an eye-opening study that demonstrated just how much larger gout patients’ total body urate burden actually is compared with what’s apparent clinically. Investigators at the University of British Columbia, Vancouver, used dual-energy CT to assess urate deposits in 20 consecutive patients with tophaceous gout and 10 controls with other arthritic conditions. Physical evaluation of the gout patients turned up 111 areas of urate deposition; dual-energy CT revealed 440 such areas. The mean total urate volume was a hefty 40.2 cm3 (Ann. Rheum. Dis. 2009;68:1609-12).
"There’s a lot more tophi under the surface," Dr. Pillinger commented.
Pegloticase is a recombinant porcine uricase that’s modified with a baboon N-terminus. It’s pegylated to reduce immunogenicity to the uricase and increase stability and half-life. Paradoxically, the drug is still quite immunogenic because many patients develop antibodies to the polyethylene glycol used in pegylation.
The drug’s urate-lowering effect is unmatched. Within 12-24 hours of the first dose, the plasma uric acid level plummets to almost nothing.
"What happens is that very, very quickly these patients are going to split into two groups. For one group this is the greatest drug in the world; their uric acid remains almost undetectable – and that’s in our sickest refractory patients. And then there’s another group that starts to fail. It’s in the neighborhood of 30%-40% of patients, so it’s a real problem. We know they’re failing because their uric acid level starts rising. They’re making antibodies and inactivating the drug every time it’s given. And they’re the ones who get bad infusion reactions," the rheumatologist explained.
The solution to using pegloticase safely is to routinely measure serum urate 1-2 days before each infusion. If the serum urate climbs to 6 mg/dL on one or two occasions, it’s time to discontinue the drug.
"For everybody else, they’re going to do really, really well," Dr. Pillinger said.
A key point emphasized in the 2012 ACR gout guidelines (Arthritis Care Res. 2012;64:1431-46; 1447-61) is that when patients go on pegloticase, all other urate-lowering therapies must be stopped as a matter of safety. Otherwise, it’s impossible to use the pre-infusion plasma urate measurement to determine if pegloticase has stopped working.
The ACR guidelines recommend pegloticase as third-line urate-lowering therapy in patients who are not at target despite maximum-dose therapy with a xanthine oxidase inhibitor plus second-line therapy with probenecid, losartan, or fenofibrate.
Dr. Pillinger reported having received research grants from Savient, which markets pegloticase, and Takeda.
SNOWMASS, COLO. – Pegloticase (Krystexxa) is a gout drug that’s expensive, inconveniently administered by intravenous infusion every 2 weeks, and saddled with a substantial rate of immunogenicity, with infusion reactions that can include anaphylaxis.
So why does gout authority Dr. Michael H. Pillinger call pegloticase "a greatly underestimated and underutilized drug"? And why do the current American College of Rheumatology gout guidelines recommend pegloticase for refractory gout?
"Nothing else we have will get rid of tophi the way this drug gets rid of tophi," Dr. Pillinger explained at the Winter Rheumatology Symposium sponsored by the American College of Rheumatology.
"Why do we care about that? Because tophi are erosive, they’re damaging, and also because they’re much more extensive than we think they are," said Dr. Pillinger, a rheumatologist and director of the crystal diseases study group at New York University.
Besides, the safety concern regarding this powerhouse urate-lowering drug has been resolved. The infusion reactions are readily avoidable. Pegloticase is not a drug rheumatologists should be scared of, he emphasized.
Dr. Pillinger cited an eye-opening study that demonstrated just how much larger gout patients’ total body urate burden actually is compared with what’s apparent clinically. Investigators at the University of British Columbia, Vancouver, used dual-energy CT to assess urate deposits in 20 consecutive patients with tophaceous gout and 10 controls with other arthritic conditions. Physical evaluation of the gout patients turned up 111 areas of urate deposition; dual-energy CT revealed 440 such areas. The mean total urate volume was a hefty 40.2 cm3 (Ann. Rheum. Dis. 2009;68:1609-12).
"There’s a lot more tophi under the surface," Dr. Pillinger commented.
Pegloticase is a recombinant porcine uricase that’s modified with a baboon N-terminus. It’s pegylated to reduce immunogenicity to the uricase and increase stability and half-life. Paradoxically, the drug is still quite immunogenic because many patients develop antibodies to the polyethylene glycol used in pegylation.
The drug’s urate-lowering effect is unmatched. Within 12-24 hours of the first dose, the plasma uric acid level plummets to almost nothing.
"What happens is that very, very quickly these patients are going to split into two groups. For one group this is the greatest drug in the world; their uric acid remains almost undetectable – and that’s in our sickest refractory patients. And then there’s another group that starts to fail. It’s in the neighborhood of 30%-40% of patients, so it’s a real problem. We know they’re failing because their uric acid level starts rising. They’re making antibodies and inactivating the drug every time it’s given. And they’re the ones who get bad infusion reactions," the rheumatologist explained.
The solution to using pegloticase safely is to routinely measure serum urate 1-2 days before each infusion. If the serum urate climbs to 6 mg/dL on one or two occasions, it’s time to discontinue the drug.
"For everybody else, they’re going to do really, really well," Dr. Pillinger said.
A key point emphasized in the 2012 ACR gout guidelines (Arthritis Care Res. 2012;64:1431-46; 1447-61) is that when patients go on pegloticase, all other urate-lowering therapies must be stopped as a matter of safety. Otherwise, it’s impossible to use the pre-infusion plasma urate measurement to determine if pegloticase has stopped working.
The ACR guidelines recommend pegloticase as third-line urate-lowering therapy in patients who are not at target despite maximum-dose therapy with a xanthine oxidase inhibitor plus second-line therapy with probenecid, losartan, or fenofibrate.
Dr. Pillinger reported having received research grants from Savient, which markets pegloticase, and Takeda.
SNOWMASS, COLO. – Pegloticase (Krystexxa) is a gout drug that’s expensive, inconveniently administered by intravenous infusion every 2 weeks, and saddled with a substantial rate of immunogenicity, with infusion reactions that can include anaphylaxis.
So why does gout authority Dr. Michael H. Pillinger call pegloticase "a greatly underestimated and underutilized drug"? And why do the current American College of Rheumatology gout guidelines recommend pegloticase for refractory gout?
"Nothing else we have will get rid of tophi the way this drug gets rid of tophi," Dr. Pillinger explained at the Winter Rheumatology Symposium sponsored by the American College of Rheumatology.
"Why do we care about that? Because tophi are erosive, they’re damaging, and also because they’re much more extensive than we think they are," said Dr. Pillinger, a rheumatologist and director of the crystal diseases study group at New York University.
Besides, the safety concern regarding this powerhouse urate-lowering drug has been resolved. The infusion reactions are readily avoidable. Pegloticase is not a drug rheumatologists should be scared of, he emphasized.
Dr. Pillinger cited an eye-opening study that demonstrated just how much larger gout patients’ total body urate burden actually is compared with what’s apparent clinically. Investigators at the University of British Columbia, Vancouver, used dual-energy CT to assess urate deposits in 20 consecutive patients with tophaceous gout and 10 controls with other arthritic conditions. Physical evaluation of the gout patients turned up 111 areas of urate deposition; dual-energy CT revealed 440 such areas. The mean total urate volume was a hefty 40.2 cm3 (Ann. Rheum. Dis. 2009;68:1609-12).
"There’s a lot more tophi under the surface," Dr. Pillinger commented.
Pegloticase is a recombinant porcine uricase that’s modified with a baboon N-terminus. It’s pegylated to reduce immunogenicity to the uricase and increase stability and half-life. Paradoxically, the drug is still quite immunogenic because many patients develop antibodies to the polyethylene glycol used in pegylation.
The drug’s urate-lowering effect is unmatched. Within 12-24 hours of the first dose, the plasma uric acid level plummets to almost nothing.
"What happens is that very, very quickly these patients are going to split into two groups. For one group this is the greatest drug in the world; their uric acid remains almost undetectable – and that’s in our sickest refractory patients. And then there’s another group that starts to fail. It’s in the neighborhood of 30%-40% of patients, so it’s a real problem. We know they’re failing because their uric acid level starts rising. They’re making antibodies and inactivating the drug every time it’s given. And they’re the ones who get bad infusion reactions," the rheumatologist explained.
The solution to using pegloticase safely is to routinely measure serum urate 1-2 days before each infusion. If the serum urate climbs to 6 mg/dL on one or two occasions, it’s time to discontinue the drug.
"For everybody else, they’re going to do really, really well," Dr. Pillinger said.
A key point emphasized in the 2012 ACR gout guidelines (Arthritis Care Res. 2012;64:1431-46; 1447-61) is that when patients go on pegloticase, all other urate-lowering therapies must be stopped as a matter of safety. Otherwise, it’s impossible to use the pre-infusion plasma urate measurement to determine if pegloticase has stopped working.
The ACR guidelines recommend pegloticase as third-line urate-lowering therapy in patients who are not at target despite maximum-dose therapy with a xanthine oxidase inhibitor plus second-line therapy with probenecid, losartan, or fenofibrate.
Dr. Pillinger reported having received research grants from Savient, which markets pegloticase, and Takeda.
EXPERT ANALYSIS FROM THE WINTER RHEUMATOLOGY SYMPOSIUM
Striking trends emerge in SLE joint replacement
SNOWMASS, COLO. – Total knee replacement surgery rates in patients with systemic lupus erythematosus jumped sixfold nationally during a recent 15-year span – and buried within this statistic is some very good news.
The sharp rise in total knee replacement (TKR) among systemic lupus erythematosus (SLE) patients has been driven by a hefty increase in operations performed for osteoarthritis, while TKR for active SLE in the knee has declined. These trends reflect the increased longevity of patients with SLE resulting from improved medical management. For the first time, large numbers of SLE patients are surviving to an age when they, like other Americans, are more vulnerable to osteoarthritis, Dr. Susan M. Goodman explained at the Winter Rheumatology Symposium sponsored by the American College of Rheumatology.
"Lupus is no longer the highly mortal disease that it was," she observed. "Clearly, patients are surviving and – I don’t know how else to put it – they’ve become middle-aged women who are having knee replacements, which is kind of a success."
She presented highlights of a soon-to-be-published study involving analysis of 10 state databases including nearly 2.8 million arthroplasties performed during 1991-2005. The rate of TKR in SLE patients climbed sixfold from 0.03 per 100,000 population in 1991 to 0.18 per 100,000 in 2005. Meanwhile, total hip replacement (THR) in SLE patients showed a modest but statistically significant increase from 0.11 to 0.18 cases per 100,000.
The proportion of lupus patients undergoing arthroplasty for avascular necrosis fell from 53% in 1991 to 24% in 2005, while the proportion undergoing arthroplasty because they developed osteoarthritis went from 23% to 61%.
Virtually all of the increase in total arthroplasties among SLE patients occurred in women aged 45 years and older. Their rate more than tripled during the study years, going from 0.076 to 0.271 cases per 100,000. Rates in female SLE patients aged 44 years and younger actually took a significant drop from 0.073 to 0.067 per 100,000. Rates in males aged 44 and younger remained flat over time, while men aged 45 and up showed a modest increase from a low baseline rate of 0.009 cases per 100,000 in 1991 to 0.034 per 100,000 in 2005, according to Dr. Goodman, a rheumatologist at the Hospital for Special Surgery and Cornell University, New York.
The proportion of TKRs among all arthroplasties performed in SLE patients increased from 16% in 1991 to 48% in 2005. Meanwhile, THRs decreased from 66% of all arthroplasties to 40%. Other joint replacements didn’t change much over time.
A particularly striking finding in the study was that the mean age at the time of arthroplasty in SLE patients increased by nearly a decade – 47.3 years in 1991 to 56.8 years in 2005. In contrast, the mean age at arthroplasty for osteoarthritis patients without SLE decreased from 71.5 to 69.0 years.
Dr. Goodman turned to additional studies by her research group and other investigators to provide a picture of arthroplasty outcomes in SLE patients.
In-hospital postoperative mortality was found to be increased in SLE patients, compared with rheumatoid arthritis patients or controls undergoing TKR or THR in a study of more than 1.5 million TKRs and THRs included in the Nationwide Inpatient Sample for 1993-2006. The Nationwide Inpatient Sample is the largest all-payer inpatient health care database in the United States.
In a multivariate logistic regression analysis adjusted for comorbidities, hospital type, and other potential confounders, investigators at Stanford (Calif.) University found that SLE patients undergoing THR had a 3.5-fold increased risk of death, compared with controls. This was driven by a 4.9-fold increased death risk in SLE patients undergoing nonelective THR or TKR, typically because of a fracture. In contrast, the rate of in-hospital death following TKR or THR in rheumatoid arthritis patients wasn’t significantly different from controls. The one comorbidity present on admission that was associated with markedly increased postoperative mortality was renal disease in SLE patients (J. Rheumatol. 2010;37:1467-72).
"Baseline renal dysfunction really seems to be a marker in lupus patients for bad perioperative outcome," Dr. Goodman observed, adding that there is a need for "increased vigilance" regarding this comorbidity.
A study of 57 SLE patients and 107 age-matched osteoarthritis patients who underwent THR at the Hospital for Special Surgery demonstrated that the lupus patients had more baseline comorbidities as reflected in their mean Charlson Comorbidity Index of 1.9, compared with 0.3 in the osteoarthritis group. Seventy-nine percent of the SLE patients, but none of the osteoarthritis patients, were on immunosuppressant therapy. The lupus patients had a 19% incidence of postoperative major adverse events, including deep vein thrombosis, arrhythmia, acute renal insufficiency, or additional surgery, compared with a 6% rate in the osteoarthritis group. The 6-day mean length of stay in the SLE group was a full day longer than that of the osteoarthritis patients, according to Dr. Goodman.
Another Hospital for Special Surgery study included 56 SLE patients undergoing THR and 45 with TKR, as well as 108 age-matched controls undergoing THR and 89 with TKR. The SLE patients had significantly worse baseline Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC) pain and function scores than did the osteoarthritis patients. At 2 years of follow-up, however, all four groups ended up with very good pain and function outcomes, with WOMAC scores in the 80-92 range.
Yet despite these excellent outcomes, the SLE patients still felt more limited by their chronic disease. This was reflected in their lower health-related quality of life on the SF-36 physical component summary score at 2 years of follow-up: 39 in the SLE THR patients, compared with 50.1 in the osteoarthritis THR group, and 38 in the SLE TKR patients, compared with 48.4 in the osteoarthritis controls.
This and other studies paint a picture of contemporary SLE patients undergoing TKR as more closely resembling osteoarthritis patients with TKR than SLE patients undergoing THR. The average age of the SLE TKR patients, at 62.4 years, was 8 years older than the SLE THR group. The SLE TKR group’s mean body mass index of 31.5 kg/m2 was 5 kg/m2 greater than in the SLE THR group. And none of the SLE TKR patients had avascular necrosis, compared with one-third of those undergoing THR.
Dr. Goodman reported having no relevant financial relationships.
SNOWMASS, COLO. – Total knee replacement surgery rates in patients with systemic lupus erythematosus jumped sixfold nationally during a recent 15-year span – and buried within this statistic is some very good news.
The sharp rise in total knee replacement (TKR) among systemic lupus erythematosus (SLE) patients has been driven by a hefty increase in operations performed for osteoarthritis, while TKR for active SLE in the knee has declined. These trends reflect the increased longevity of patients with SLE resulting from improved medical management. For the first time, large numbers of SLE patients are surviving to an age when they, like other Americans, are more vulnerable to osteoarthritis, Dr. Susan M. Goodman explained at the Winter Rheumatology Symposium sponsored by the American College of Rheumatology.
"Lupus is no longer the highly mortal disease that it was," she observed. "Clearly, patients are surviving and – I don’t know how else to put it – they’ve become middle-aged women who are having knee replacements, which is kind of a success."
She presented highlights of a soon-to-be-published study involving analysis of 10 state databases including nearly 2.8 million arthroplasties performed during 1991-2005. The rate of TKR in SLE patients climbed sixfold from 0.03 per 100,000 population in 1991 to 0.18 per 100,000 in 2005. Meanwhile, total hip replacement (THR) in SLE patients showed a modest but statistically significant increase from 0.11 to 0.18 cases per 100,000.
The proportion of lupus patients undergoing arthroplasty for avascular necrosis fell from 53% in 1991 to 24% in 2005, while the proportion undergoing arthroplasty because they developed osteoarthritis went from 23% to 61%.
Virtually all of the increase in total arthroplasties among SLE patients occurred in women aged 45 years and older. Their rate more than tripled during the study years, going from 0.076 to 0.271 cases per 100,000. Rates in female SLE patients aged 44 years and younger actually took a significant drop from 0.073 to 0.067 per 100,000. Rates in males aged 44 and younger remained flat over time, while men aged 45 and up showed a modest increase from a low baseline rate of 0.009 cases per 100,000 in 1991 to 0.034 per 100,000 in 2005, according to Dr. Goodman, a rheumatologist at the Hospital for Special Surgery and Cornell University, New York.
The proportion of TKRs among all arthroplasties performed in SLE patients increased from 16% in 1991 to 48% in 2005. Meanwhile, THRs decreased from 66% of all arthroplasties to 40%. Other joint replacements didn’t change much over time.
A particularly striking finding in the study was that the mean age at the time of arthroplasty in SLE patients increased by nearly a decade – 47.3 years in 1991 to 56.8 years in 2005. In contrast, the mean age at arthroplasty for osteoarthritis patients without SLE decreased from 71.5 to 69.0 years.
Dr. Goodman turned to additional studies by her research group and other investigators to provide a picture of arthroplasty outcomes in SLE patients.
In-hospital postoperative mortality was found to be increased in SLE patients, compared with rheumatoid arthritis patients or controls undergoing TKR or THR in a study of more than 1.5 million TKRs and THRs included in the Nationwide Inpatient Sample for 1993-2006. The Nationwide Inpatient Sample is the largest all-payer inpatient health care database in the United States.
In a multivariate logistic regression analysis adjusted for comorbidities, hospital type, and other potential confounders, investigators at Stanford (Calif.) University found that SLE patients undergoing THR had a 3.5-fold increased risk of death, compared with controls. This was driven by a 4.9-fold increased death risk in SLE patients undergoing nonelective THR or TKR, typically because of a fracture. In contrast, the rate of in-hospital death following TKR or THR in rheumatoid arthritis patients wasn’t significantly different from controls. The one comorbidity present on admission that was associated with markedly increased postoperative mortality was renal disease in SLE patients (J. Rheumatol. 2010;37:1467-72).
"Baseline renal dysfunction really seems to be a marker in lupus patients for bad perioperative outcome," Dr. Goodman observed, adding that there is a need for "increased vigilance" regarding this comorbidity.
A study of 57 SLE patients and 107 age-matched osteoarthritis patients who underwent THR at the Hospital for Special Surgery demonstrated that the lupus patients had more baseline comorbidities as reflected in their mean Charlson Comorbidity Index of 1.9, compared with 0.3 in the osteoarthritis group. Seventy-nine percent of the SLE patients, but none of the osteoarthritis patients, were on immunosuppressant therapy. The lupus patients had a 19% incidence of postoperative major adverse events, including deep vein thrombosis, arrhythmia, acute renal insufficiency, or additional surgery, compared with a 6% rate in the osteoarthritis group. The 6-day mean length of stay in the SLE group was a full day longer than that of the osteoarthritis patients, according to Dr. Goodman.
Another Hospital for Special Surgery study included 56 SLE patients undergoing THR and 45 with TKR, as well as 108 age-matched controls undergoing THR and 89 with TKR. The SLE patients had significantly worse baseline Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC) pain and function scores than did the osteoarthritis patients. At 2 years of follow-up, however, all four groups ended up with very good pain and function outcomes, with WOMAC scores in the 80-92 range.
Yet despite these excellent outcomes, the SLE patients still felt more limited by their chronic disease. This was reflected in their lower health-related quality of life on the SF-36 physical component summary score at 2 years of follow-up: 39 in the SLE THR patients, compared with 50.1 in the osteoarthritis THR group, and 38 in the SLE TKR patients, compared with 48.4 in the osteoarthritis controls.
This and other studies paint a picture of contemporary SLE patients undergoing TKR as more closely resembling osteoarthritis patients with TKR than SLE patients undergoing THR. The average age of the SLE TKR patients, at 62.4 years, was 8 years older than the SLE THR group. The SLE TKR group’s mean body mass index of 31.5 kg/m2 was 5 kg/m2 greater than in the SLE THR group. And none of the SLE TKR patients had avascular necrosis, compared with one-third of those undergoing THR.
Dr. Goodman reported having no relevant financial relationships.
SNOWMASS, COLO. – Total knee replacement surgery rates in patients with systemic lupus erythematosus jumped sixfold nationally during a recent 15-year span – and buried within this statistic is some very good news.
The sharp rise in total knee replacement (TKR) among systemic lupus erythematosus (SLE) patients has been driven by a hefty increase in operations performed for osteoarthritis, while TKR for active SLE in the knee has declined. These trends reflect the increased longevity of patients with SLE resulting from improved medical management. For the first time, large numbers of SLE patients are surviving to an age when they, like other Americans, are more vulnerable to osteoarthritis, Dr. Susan M. Goodman explained at the Winter Rheumatology Symposium sponsored by the American College of Rheumatology.
"Lupus is no longer the highly mortal disease that it was," she observed. "Clearly, patients are surviving and – I don’t know how else to put it – they’ve become middle-aged women who are having knee replacements, which is kind of a success."
She presented highlights of a soon-to-be-published study involving analysis of 10 state databases including nearly 2.8 million arthroplasties performed during 1991-2005. The rate of TKR in SLE patients climbed sixfold from 0.03 per 100,000 population in 1991 to 0.18 per 100,000 in 2005. Meanwhile, total hip replacement (THR) in SLE patients showed a modest but statistically significant increase from 0.11 to 0.18 cases per 100,000.
The proportion of lupus patients undergoing arthroplasty for avascular necrosis fell from 53% in 1991 to 24% in 2005, while the proportion undergoing arthroplasty because they developed osteoarthritis went from 23% to 61%.
Virtually all of the increase in total arthroplasties among SLE patients occurred in women aged 45 years and older. Their rate more than tripled during the study years, going from 0.076 to 0.271 cases per 100,000. Rates in female SLE patients aged 44 years and younger actually took a significant drop from 0.073 to 0.067 per 100,000. Rates in males aged 44 and younger remained flat over time, while men aged 45 and up showed a modest increase from a low baseline rate of 0.009 cases per 100,000 in 1991 to 0.034 per 100,000 in 2005, according to Dr. Goodman, a rheumatologist at the Hospital for Special Surgery and Cornell University, New York.
The proportion of TKRs among all arthroplasties performed in SLE patients increased from 16% in 1991 to 48% in 2005. Meanwhile, THRs decreased from 66% of all arthroplasties to 40%. Other joint replacements didn’t change much over time.
A particularly striking finding in the study was that the mean age at the time of arthroplasty in SLE patients increased by nearly a decade – 47.3 years in 1991 to 56.8 years in 2005. In contrast, the mean age at arthroplasty for osteoarthritis patients without SLE decreased from 71.5 to 69.0 years.
Dr. Goodman turned to additional studies by her research group and other investigators to provide a picture of arthroplasty outcomes in SLE patients.
In-hospital postoperative mortality was found to be increased in SLE patients, compared with rheumatoid arthritis patients or controls undergoing TKR or THR in a study of more than 1.5 million TKRs and THRs included in the Nationwide Inpatient Sample for 1993-2006. The Nationwide Inpatient Sample is the largest all-payer inpatient health care database in the United States.
In a multivariate logistic regression analysis adjusted for comorbidities, hospital type, and other potential confounders, investigators at Stanford (Calif.) University found that SLE patients undergoing THR had a 3.5-fold increased risk of death, compared with controls. This was driven by a 4.9-fold increased death risk in SLE patients undergoing nonelective THR or TKR, typically because of a fracture. In contrast, the rate of in-hospital death following TKR or THR in rheumatoid arthritis patients wasn’t significantly different from controls. The one comorbidity present on admission that was associated with markedly increased postoperative mortality was renal disease in SLE patients (J. Rheumatol. 2010;37:1467-72).
"Baseline renal dysfunction really seems to be a marker in lupus patients for bad perioperative outcome," Dr. Goodman observed, adding that there is a need for "increased vigilance" regarding this comorbidity.
A study of 57 SLE patients and 107 age-matched osteoarthritis patients who underwent THR at the Hospital for Special Surgery demonstrated that the lupus patients had more baseline comorbidities as reflected in their mean Charlson Comorbidity Index of 1.9, compared with 0.3 in the osteoarthritis group. Seventy-nine percent of the SLE patients, but none of the osteoarthritis patients, were on immunosuppressant therapy. The lupus patients had a 19% incidence of postoperative major adverse events, including deep vein thrombosis, arrhythmia, acute renal insufficiency, or additional surgery, compared with a 6% rate in the osteoarthritis group. The 6-day mean length of stay in the SLE group was a full day longer than that of the osteoarthritis patients, according to Dr. Goodman.
Another Hospital for Special Surgery study included 56 SLE patients undergoing THR and 45 with TKR, as well as 108 age-matched controls undergoing THR and 89 with TKR. The SLE patients had significantly worse baseline Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC) pain and function scores than did the osteoarthritis patients. At 2 years of follow-up, however, all four groups ended up with very good pain and function outcomes, with WOMAC scores in the 80-92 range.
Yet despite these excellent outcomes, the SLE patients still felt more limited by their chronic disease. This was reflected in their lower health-related quality of life on the SF-36 physical component summary score at 2 years of follow-up: 39 in the SLE THR patients, compared with 50.1 in the osteoarthritis THR group, and 38 in the SLE TKR patients, compared with 48.4 in the osteoarthritis controls.
This and other studies paint a picture of contemporary SLE patients undergoing TKR as more closely resembling osteoarthritis patients with TKR than SLE patients undergoing THR. The average age of the SLE TKR patients, at 62.4 years, was 8 years older than the SLE THR group. The SLE TKR group’s mean body mass index of 31.5 kg/m2 was 5 kg/m2 greater than in the SLE THR group. And none of the SLE TKR patients had avascular necrosis, compared with one-third of those undergoing THR.
Dr. Goodman reported having no relevant financial relationships.
EXPERT ANALYSIS FROM THE WINTER RHEUMATOLOGY SYMPOSIUM
