Hyaluronic Acid Injections at the ACR 2015 Meeting in San Francisco

There have been two publications on hyaluronic acid injections at the ACR 2015 Annual Meeting in San Francisco.

Kevin Ong and colleagues analyzed retrospective data: “Hyaluronic Acid Injections in Knee Osteoarthritis Patients Are Associated with Delay to Knee Arthroplasty”. They concluded: “Our analysis of elderly knee OA patients showed a significantly longer delay to KA [knee arthroplasty] for those who were treated with HA [hyaluronic acid].” The authors presented a retrospective, observational study, which cannot take into account the placebo effect of an injection. It lacks a control group. Or do we have a control group?

Astrid in “Fringe” asked Dr. Walter Bishop: “What’s this?” And Walter answered: “A watermelon as a control group.”

I don’t see the two groups comparable; the second group isn't a control group. The time intervals are differently fixed: one with the treatment and the other one arbitrarily.

There may be other reasons as well: different coping attitudes (one trying to avoid arthropasty and the other wishing an arthroplasty), waiting for therapeutic effect or others.

All in all, I don’t think that this study has a good point to convince us of using hyaluronic acid in delaying the time to knee arthroplasty.

Gurjit S. Kaeley and colleagues also used retrospective data in their study: “Utilization of Viscosupplementation: 2011 – 2013”. The authors wanted to estimate and compare the prevalence and cost of Viscosupplemention utilization as recent “ American Academy of Orthopedic Surgeons (AAOS) guidelines have strongly recommended against use of hyaluronic acid because of lack of clinical improvement compared with placebo.” The authors concluded: “This study highlights the significant cost of VS [viscosupplementation ] in the Medicare population. […] In view of the negative recommendations by the AAOS [American Academy of Orthopedic Surgeons] against the use of Hyaluronic acid joint injections, the current trajectory of use of Hyaluronic acid may not represent optimal value care.”

Hyaluronic acid in knee osteoarthritis hasn’t proven efficacy like clinical improvement compared with placebo or delaying the time to knee arthroplasty. Therefore guidelines recommend against using it.

In Germany hyaluronic acid injections aren’t covered by the compulsory health insurance system, so patients have to pay for injection and medication.

I would not use hyaluronic acid in knee osteoarthritis.

References:

Ong K, Anderson A, Lau E, Niazi F, Fierlinger A, Kurtz S, Altman R. Hyaluronic Acid Injections in Knee Osteoarthritis Patients Are Associated with Delay to Knee Arthroplasty [abstract]. Arthritis Rheumatol. 2015; 67 (suppl 10). http://acrabstracts.org/abstract/hyaluronic-acid-injections-in-knee-osteoarthritis-patients-are-associated-with-delay-to-knee-arthroplasty/. Accessed November 16, 2015.

Kaeley GS, Thway M, Dodani S. Utilization of Viscosupplementation: 2011 – 2013 [abstract]. Arthritis Rheumatol. 2015; 67 (suppl 10). http://acrabstracts.org/abstract/utilization-of-viscosupplementation-2011-2013/. Accessed November 16, 2015.

Hyaluronic acid injection for Knee Osteoarthritis

Rheumatology News has an article on a study telling us “Hyaluronic acid injection for knee OA as effective as NSAIDs in short term” (Links are listed below).

The study is from Japan. It’s a multicenter, randomized, open-label, parallel-group, non-inferiority comparison study. One group received a weekly injection injection into the (one?) knee for five weeks and the other group received three times 60 mg of loxoprofen, which is an NSAID of the same group like ketoprofen or ibuprofen. Loxoprofen is only available in Japan, Mexico, Brazil, Argentina, and India. The primary endpoint was the percentage change in the patient-oriented outcome measure for knee OA, the Japanese Knee Osteoarthritis Measure (JKOM) score. Rheumatology News tells about the secondary endpoint: “and their percent change from baseline in pain as rated on a 0- to 100-point visual analog scale (VAS, secondary endpoint).”

Results: "The difference in the percentage changes of the JKOM score between the two intervention arms (IA-HA; - 34.7 % (P < 0.001), NSAID; - 32.2 % (P < 0.001)) was - 2.5 % (95 % confidence interval (CI): - 14.0 to 9.1), indicating IA-HA was not inferior to NSAID. The frequency of both withdrawal and adverse events in the IA-HA group were significantly lower than those in the NSAID group (P < 0.026 and 0.004, respectively)."

The study tells us, that after five weeks of treatment the effects of hyaluronic acid injection for knee OA is equal to an NSAID. How about the first two weeks? Is hyaluronic acid working or the injection itself? Invasive manipulations have a high percentage of placebo effect, but we do not have a placebo control group. We don’t even know if the control group is disappointed not getting their injections and therefore have less pain relief. Withdrawal in the NSAID group had been higher, but the use of gastro protective agents has only been allowed and not been mandatory.

The study has been perfectly done, but it fails to prove that hyaluronic acid injection for knee OA is the road to follow.

Links:

Article on Rheumatology News - http://www.rheumatologynews.com/index.php?id=8844&tx_ttnews[tt_news]=235121&cHash=04c039bf543c2984f1ad4aa5f1b6af91&utm_medium=twitter&utm_source=twitterfeed

Abstract of the study - http://arthritis-research.com/content/16/1/R18/abstract

Loxoprofen on Wikipedia - http://en.wikipedia.org/wiki/Loxoprofen