Osteoarthritis: Part I
October 1, 2013
I’ve been an Associate Editor for CJSM now for six months, and so some of you in the blog world may already know a little bit of my background as it has come out over time in my various posts.
For those of you who may be new readers of this blog, I thought for today’s post it was important for me to let you know that I work at Nationwide Children’s Hospital, the pediatric hospital affiliate of Ohio State University, and my specialty is pediatric sports medicine.
So……I don’t manage a lot of osteoarthritis (OA) in my current practice.
However, I didn’t narrow my clinical scope of practice to the younger crowd until 2010, and I have managed my fair share of OA in my career, injecting plenty of knees with hyaluronic acid derivatives, encouraging weight management and low impact exercise…….Now, I suppose I’m more on the end of the spectrum of primary prevention of the disease: if I manage my young patients’ knee osteochondritis dissecans properly, perhaps I can spare them from degenerative joint disease later in life.
I’m not telling anyone reading this something they don’t know already when I write that career paths are varied in modern medicine. There’ s no telling if I’ll be taking care of kids exclusively in 10 years. We all have mandates from Certification Boards requiring us to stay abreast of the current medical literature; we’re tested on it every few years now, as Maintenance of Certification is a phenomenon here to stay. Forces like these make it incumbent that I read and ‘stay on top of’ developments in the world of OA diagnosis and management, even if I am not seeing much of this disease in my current practice.
After all, OA is the leading cause of chronic disability among older adults in the United States. That’s a disease worth knowing about.
I thought, therefore, that I would share with you a couple of interesting studies that have come out recently on major issues in the world of osteoarthritis. Both studies were just published within the last month: the first, “Shared Decision Making in Patients with Osteoarthritis of the Hip and Knee,” published in the Journal of Bone and Joint Surgery (JBJS), I will discuss in my next blog post. And the second, “Effects of Intensive Diet and Exercise on Knee Joint Loads, Inflammation, and Clinical Outcomes Among Overweight and Obese Adults with Knee Osteoarthritis,” published in the Journal of the American Medical Association (JAMA), I will review now. They are both large, high quality evidence (Level 1) studies which focus on low tech, low cost interventions that have the potential of having major clinical impact. They are both studies primary care sports/MSK clinicians like myself might be expected to be aware of.
The “Intensive Diet and Exercise in Arthritis (IDEA)” study published in JAMA looked at the effect of diet (D), exercise (E), and diet and exercise (D + E) on mechanistic outcomes (knee joint compressive forces and IL-6 levels). The study also tracked secondary outcome measures including the WOMAC pain and function levels and the SF-36 Health Related Quality of Life (HRQoL) scores.
The authors conducted this single-blind, randomized controlled trial over the course of 5 years. 454 community-dwelling individuals with mild to moderate knee OA were enrolled and randomized; all were older adults (age > 55) and overweight or obese (BMI from 27 – 41). Individuals were randomized into three intervention groups: E, D, and D + E (E was defined as the comparative group). 399 individuals (88% of the enrollees) completed the 18 month interventions to which they were assigned. An intention-to-treat analysis was done.
Among the items of information I gleaned from this study was the use of IL-6 as a marker of disease in OA. Again, it has been several years since I have actively taken care of a patient with knee OA, and this study reminds me of the importance of staying on top of journal reading. “Things” change quickly in medicine.
The results emphasized the importance of weight loss and dietary management in this population, as the statistically significant findings for the primary outcome measures included: the D intervention was superior to E alone in lowering knee compressive forces and both the D and the D + E interventions were superior to E alone in lowering IL-6 levels. Considering the secondary outcome measures only the D + E intervention had significant findings when compared with E alone, in all three patient oriented outcome measures (WOMAC pain, WOMAC function, and SF-36 HRQoL).
The dietary intervention was, as the study’s title would have it, ‘intensive.’ The goal for the D and D + E groups was a 10% weight loss, achieved by eating a diet with a daily dietary energy intake deficit of 800 to 1000 kcal (with a minimum of 1100 kcal for women and 1200 kcal for men). The E group received what seems to be a less ‘intensive’ intervention: 3 days a week for the 18 months participants were put through a one hour mixed workout (including aerobic, anaerobic, resistance, and cool down components). For 6 months this intervention was center-based, but at the 6 month mark participants could opt for a home program, if they preferred. Interestingly, retention rates were essentially the same for all three groups: 89% for E, 85% for D, and 89% for D + E.
I was intrigued by the results of this study for several reasons. Though the news that weight loss and exercise will help OA is not new, this is a large, well-designed, Level 1 study that confirms this medical information we pass on to our patients. I think it is also important to note that to achieve weight loss, dietary restructuring needs to be significant. A little might help, but the ‘full monty’ of 10% loss of body weight with a 1000 kcal/d deficit over 18 months is what gave these results. Moreover, I was surprised to learn of the importance of dietary change in the management of OA: in this study, diet seemed to have a more powerful effect on outcomes than exercise. And, finally, as I had mentioned earlier, i learned about the biomarker IL-6.
I look forward to sharing with you what I learned from the JBJS study in my next posting. If any of the readership knows of a recent, and especially good OA study they want to pass on to me, by all means do.