— Better efficacy and no pricier over time

by John Gever, Contributing Writer, MedPage Today January 24, 2022

Although physical therapy for osteoarthritis of the knee costs more than an intra-articular steroid injection, it’s cost-effective when clinical outcomes a year later are taken into account, researchers said.

A secondary analysis of data from 156 participants in the SMART trial indicated that total 1-year medical costs averaged $2,113 for patients receiving steroid shots versus $2,131 for a group assigned to physical therapy, reported Daniel Rhon, DPT, DSc, PhD, of Brooke Army Medical Center at Fort Sam Houston in Texas, and colleagues.

While these costs were nearly identical, physical therapy was the winner when examining gains in quality-adjusted life-years (QALYs). Those in the physical therapy group had mean improvements of 0.76 QALYs, compared with 0.69 with steroid injections (P=0.003), the researchers noted in JAMA Network Open.

For knee-related medical costs over 1 year, this made physical therapy the better option, with an incremental cost-effectiveness ratio (ICER) of $8,103 per QALY gained; this figure rose to $28,271 per QALY for all medical costs. Both of these “are much less than the common [willingness to pay] thresholds of $50,000 and $100,000” per QALY, Rhon and colleagues wrote.

“Clinicians should consider that although the initial cost of delivering physical therapy may be slightly higher than an initial glucocorticoid injection, the mean improvement in QALYs at 1 year may also be greater with physical therapy,” they concluded, adding that these considerations should be part of the shared decision-making process with patients.

Primary results from SMART were published in 2020. This randomized trial, sponsored by the U.S. Department of Defense, compared 1-year clinical outcomes in knee osteoarthritis with physical therapy versus conventional steroid injections (n=78 each). For both pain and functional ability, as measured with the Western Ontario McMaster Universities Osteoarthritis Index, known as WOMAC, physical therapy proved superior.

Physical therapy in the trial consisted of up to eight professionally led sessions over a 4- to 6-week period, with additional sessions available at participants’ request. Steroid injections included 40 mg of triamcinolone plus 7 mL of 1% lidocaine. All patients in this group received one upon enrollment and could have up to three more at clinicians’ discretion; the mean number actually given was 2.6.

Mean patient age and body mass index were 56 and 31, respectively. WOMAC scores averaged 108 at baseline, reaching 37 at 1 year with physical therapy and 56 with injections.

For the new analysis, Rhon’s group calculated ICER values by dividing the differences in medical costs (knee-related and total for any reason) between treatments by the differences in QALYs gained, yielding a figure expressed in dollars. The willingness-to-pay thresholds were taken from the literature; $100,000 per QALY has been the most common standard for U.S. patients, Rhon and colleagues indicated.

The new study is just the latest to cast doubt on steroid injections as first-line treatment for knee osteoarthritis. A 2019 review noted rising concerns about adverse effects from the shots, as well as uncertainty about their true benefit.

More recently, though, a study conducted among a primarily Hispanic population in Connecticut found that a combination of injections and physical therapy had the advantage of reducing therapy dropout rates — often a major problem in low-income communities.

Cost and its handmaiden, convenience, are important factors in patients’ decisions on osteoarthritis therapy, Rhon and colleagues acknowledged. “For individuals who work or have other responsibilities, the idea of one injection could appear more favorable than eight physical therapy sessions. Missing work to attend sessions can initially appear as a greater burden,” they wrote.

“However,” the group continued, “the notion that one or more glucocorticoid injections will fix the problem is also not realistic. In this trial, most patients needed multiple injections (mean, 2.6). In our trial, 14 individuals in the injection group eventually went to physical therapy, and four individuals underwent surgery. None in the physical therapy group had surgery.”

Consequently, they argued, “[p]atients should be made aware of these outcomes when considering the two treatment options, as well as the short-term efficacy of a single glucocorticoid injection, typically 1 to 6 weeks.”

Limitations to the study included that participants were drawn from military hospitals — where treatments are free to patients, thus eliminating cost as a barrier to seeking care in the first place — and outcomes could have depended on specifics of the physical therapy and steroid injections, which may vary from one practice to another.