TORONTO – comparing nearly 180,000 statin users with an equal number of propensity-matched nonusers, Jie Wei, PhD, reported at the OARSI 2019 World Congress.
Less intensive statin therapy was associated with significantly less need for joint replacement surgery in rheumatoid arthritis patients, but not in those with osteoarthritis, she said at the meeting, sponsored by the Osteoarthritis Research Society International.
“In summary, statins may reduce the risk of joint replacement, especially when given at high strength and in people with rheumatoid arthritis,” said, an epidemiologist at Massachusetts General Hospital, Boston, and Central South University in Changsha, Hunan, China.
She was quick to note that this study can’t be considered the final, definitive word on the topic, since other investigators’ studies of the relationship between statin usage and joint replacement surgery for arthritis have yielded conflicting results. However, given the thoroughly established super-favorable risk/benefit ratio of statins for the prevention of cardiovascular morbidity and mortality, the possibility of a prospective, randomized, controlled trial addressing the joint surgery issue is for ethical reasons a train that’s left the station.
Dr. Wei presented an analysis drawn from thefor the years 1989 through mid-2017. The initial sample included the medical records of 17.1 million patients, or 26% of the total U.K. population. From that massive pool, she and her coinvestigators zeroed in on 178,467 statin users and an equal number of non–statin-user controls under the care of 718 primary care physicians, with the pairs propensity score-matched on the basis of age, gender, locality, comorbid conditions, nonstatin medications, lifestyle factors, and duration of rheumatoid arthritis or osteoarthritis. The mean age of the matched pairs was 62 years, 52% were women, and the mean prospective follow-up was 6.5 years.
The use of high-intensity statin therapy – for example, atorvastatin at 40-80 mg/day or rosuvastatin (Crestor) at 20-40 mg/day – was independently associated with a 21% reduction in the risk of knee or hip replacement surgery for osteoarthritis and a 90% reduction for rheumatoid arthritis, compared with statin nonusers. Notably, joint replacement surgery for osteoarthritis was roughly 25-fold more common than for rheumatoid arthritis.
Statin therapy overall, including the more widely prescribed low- and intermediate-intensity regimens, was associated with a 23% reduction in joint replacement surgery for rheumatoid arthritis, compared with statin nonusers, but had no significant impact on surgery for the osteoarthritis population.
A couple of distinguished American rheumatologists in the audience rose to voice reluctance about drawing broad conclusions from this study.
“Bias, as you’ve said yourself, is a bit of a concern,” said, professor of medicine and public health and director of clinical epidemiology at Boston University.
He was troubled that the study design was such that anyone who filled as few as two statin prescriptions during the more than 6-year study period was categorized as a statin user. That, he said, muddies the waters. Does the database contain information on duration of statin therapy, and whether joint replacement surgery was more likely to occur when patients were on or off statin therapy? he asked.
It does, Dr. Wei replied, adding that she will take that suggestion for additional analysis back to her international team of coinvestigators.
“It seems to me,” said, “that the major risk of potential bias is that people who were provided high-intensity statins were prescribed that because they were at risk for or had cardiac disease.”
That high cardiovascular risk might have curbed orthopedic surgeons’ enthusiasm to operate. Thus, it would be helpful to learn whether patients who underwent joint replacement were less likely to have undergone coronary revascularization or other cardiac interventions than were those without joint replacement, according to Dr. Katz, professor of medicine and orthopedic surgery at Harvard Medical School, Boston.
Dr. Wei agreed that confounding by indication is always a possibility in an observational study such as this. Identification of a plausible mechanism by which statins might reduce the risk of joint replacement surgery in rheumatoid arthritis – something that hasn’t happened yet – would help counter such concerns.
She noted that a separate recent analysis of the U.K. Clinical Practice Research Datalink by other investigators concluded that statin therapy started up to 5 years following total hip or knee replacement was associated with a significantly reduced risk of revision arthroplasty. Moreover, the benefit was treatment duration-dependent: Patients on statin therapy for more than 5 years were 26% less likely to undergo revision arthroplasty than were those on a statin for less than 1 year ().
On the other hand, Swedish investigators found that statin use wasn’t associated with a reduced risk of consultation or surgery for osteoarthritis in a pooled analysis of four cohort studies totaling more than 132,000 Swedes followed for 7.5 years ().
Dr. Wei reported having no financial conflicts regarding the study, which was supported by the National Clinical Research Center of Geriatric Disorders in Hunan, China, and several British universities.