SNOWMASS, COLO. – During a recent 15-year period in which the annual arthroplasty rate for osteoarthritis and other noninflammatory arthritides doubled, the arthroplasty rate for rheumatoid arthritis actually declined. Moreover, the mean age at the time of arthroplasty for RA rose.
"In a time frame when utilization of total knee and total hip replacement for osteoarthritis is really skyrocketing, with younger and younger patients, I think this speaks to something pretty good going on with our RA patients," Dr. Susan M. Goodman observed at the Winter Rheumatology Symposium sponsored by the American College of Rheumatology.
Dr. Susan M. Goodman
She presented data from a soon to be published study of nearly 2.8 million arthroplasties included in 10 state databases. The arthroplasty rate for noninflammatory arthritis – the great majority of which is osteoarthritis (OA) – zoomed from 124.5/100,000 population in 1991 to 247.5/100,000 in 2005.
Meanwhile the rate of arthroplasty for RA fell slightly, albeit statistically significantly, from 4.6 to 4.5 per 100,000. The mean age at the time of arthroplasty for RA rose from 63.4 years in 1991 to 64.9 years in 2005, reported Dr. Goodman, a rheumatologist at the Hospital for Special Surgery in New York.
She turned to data from other sources to address issues related to the morbidity of arthroplasty for RA.
For example, it’s well documented that rheumatoid arthritis is associated with elevated cardiovascular risk, such that the typical RA patient has a cardiovascular morbidity burden comparable to that of someone without RA who’s 5 years older. So what does this mean for the many RA patients who come into the hospital for total hip or knee replacement?
Surprisingly, nothing. That is, data from multiple sources indicate RA patients are at no greater perioperative risk of cardiovascular events than are patients with OA undergoing the same procedures.
The take-away message? "Clearly we’re doing something right in managing our patients with RA," Dr. Goodman commented.
Similarly, an analysis of 7.75 million patients in the Nationwide Inpatient Sample database found that among RA patients undergoing intermediate-risk noncardiac surgery, such as total joint arthroplasty, the perioperative cardiovascular event rate was 0.34%, significantly less than the 1.07% rate in diabetic patients undergoing intermediate-risk surgeries. Moreover, perioperative mortality was 0.30% in the RA patients, less than half the 0.65% figure in diabetics (Arthritis Rheum. 2012;64:2429-37). These findings disproved the study hypothesis, which was that the two groups would have similar cardiovascular event rates, since both diseases are – unlike osteoarthritis – systemic inflammatory conditions associated with increased cardiovascular mortality.
"I think this means that we as rheumatologists are taking better care of our patients than the endocrinologists next door whose patients have a similar atherosclerotic burden," she continued.
Dr. Goodman was a coinvestigator in a population-based study of 351,103 total knee replacements and 157,775 total hip replacements done at 400 hospitals during 2006-2010. This retrospective analysis of an administrative database included 11,755 total knee and 5,400 total hip replacements for RA.
The prevalence of a prior history of MI, peripheral vascular disease, or cerebrovascular disease was closely similar in the RA and OA patients undergoing surgery. However, the prevalence of baseline COPD was significantly greater in the RA patients, at roughly 17.5%, or an absolute 3%-4% more than in the osteoarthritis patients.
The 30-day rates of cardiac events, venous thromboembolism, and cerebrovascular events were closely similar in the RA and OA arthroplasty patients. The RA patients undergoing total hip replacement had significantly higher rates of pulmonary compromise, infections, blood product transfusions, mechanical ventilation, and length of stay than did OA patients (Clin. Exp. Rheumatol. 2013;31:889-95). The RA patients with total knee replacement differed from their OA counterparts only in terms of greater need for transfusions and lengthier hospital stays (J. Arthroplasty 2014;29:308-13).
However, an analysis of the Hospital for Special Surgery experience failed to confirm the increased complication risks found in this study of a large administrative database. This retrospective review of adverse events within 6 months of total knee replacement in 156 RA patients and 318 OA controls showed no differences between the two groups in pneumonia, other infections, or venous thromboembolism. Moreover, the reoperation rate was 2.5% in the RA patients, compared with 8.8% in the OA group.
"The advantage of a smaller study like this is you really know who has RA and you have a lot of very granular information about the drugs they’re taking. The disadvantage, of course, is that you’re really not powered to look at major adverse events. But boy, there wasn’t even a hint of an increase in the complication rate amongst these RA patients," according to Dr. Goodman.