Researchers Find “Worsening Condition” in Osteoarthritis Incoherent

Osteoarthritis is a leading cause of disability in the United States affecting 26.9 million adults in the U.S. in 2005, according to the Centers of Disease Control and Prevention (CDC).

The CDC has described osteoarthritis (OA) as a public health problem and in March 2014, the authors of an article in Nature Reviews Rheumatology called for shifts in healthcare policy that leaned toward prevention and chronic-disease management. They called for “fundamental changes to the way we care for individuals with OA that will have an effect upon the direct and indirect costs of this disease.”

And, now, the authors of a newly published study in Arthritis Care and Research  address a very basic, but ambiguous, question in osteoarthritis care. How do physicians and patients define “worsening condition?” There is no official clinical definition so having a clear definition would aid in recommending non-surgical or surgical care, such as total joint arthroplasty.

The researchers evaluated three existing definitions of “worsening” as summarized in published literature, and asked 386 study participants undergoing non-surgical treatments to assess their condition.[[{"type":"media","view_mode":"media_crop","fid":"44859","attributes":{"alt":"©Kzenon/Shutterstock.com","class":"media-image media-image-right","id":"media_crop_6822714069858","media_crop_h":"0","media_crop_image_style":"-1","media_crop_instance":"5054","media_crop_rotate":"0","media_crop_scale_h":"0","media_crop_scale_w":"0","media_crop_w":"0","media_crop_x":"0","media_crop_y":"0","style":"font-size: 13.008px; line-height: 1.538em; float: right;","title":"©Kzenon/Shutterstock.com","typeof":"foaf:Image"}}]]

The researchers used the following scales to meausre "worsening" condition:  (1) the Western Ontario and McMaster Universities Osteoarthritis Index Global score (WOMACG) (2) Transition or (3) Composite.

Researchers found that participants who reported a worsening condition did not consistently meet the WOMACG definition of worsening symptoms. Only 12 participants met all 3 definitions of worsening. Specifically, 34 (9%) of the participants reported a worsening condition according to the WOMACG definition; 34 (9%) met the criteria for worsening for the Transition definition and 56 (15%) met the criteria for the Composite definition.   Waiting for total joint arthroplasty (TJA), a signal joint, the six-minute-walk-test, depressive symptoms, pain and age were associated with at least one definition of worsening. Previous studies have identified age, body mass index and pain intensity as predictors of radiographic progression and total joint arthroplasty.  Most of the participants were female (69%), the mean age was 66.3 years, 85% reported the knee joint as their primary complaint (signal joint) and 46% percent were waitlisted for total joint arthroplasty (TJA). Most of the participants were under the care of a rheumatologist (95%) and were referred to a dietitian (75%), an occupational therapist (55%), to a social worker (50%) and to an orthotist (50%). “Further research into this area is warranted in order to present comprehensive and targeted management of patients with hip and knee OA,” the authors wrote. 

The findings in summary as reported in Arthritis Care and Research: 

• Three different definitions of worsening were applied to a cohort participating in a chronic disease management program for hip and knee osteoarthritis.
• Participants who were “moderately” or “much” worse on the transition scale were not consistently worse according to the Minimal Important Difference using WOMAC Global scores.
• Predictors of worsening were similar between the Transition and Composite but not the WOMAC Global Score definition of worsening.
• Total joint arthroplasty waitlist status was significantly associated with the Composite definition of worsening however variables that predict worsening remain largely unknown.

The authors of the article in Nature Reviews Rheumatology found that the annual costs of employee absenteeism in the United States for patients with osteoarthritis exceeded $10 billion, which compares to $12 billion for migraines and $18 million for hypertension. And in the last decade, joint replacement procedures have doubled in the U.S. with approximately 1 million performed annually at a cost of $15 billion, wrote David J. Hunter and colleagues.

References:

"Addressing the Nation’s Most Common Cause of Disability At A Glance 2015,"

Centers for Disease Control and Prevention. David J. Hunter, Deborah Schofield and Emily Callander.

"The individual and socioeconomic impact of osteoarthritis,"

Nature Reviews Rheumatology, Perspectives.Feb 11, 2015 Jillian Eyles, et. al.

"Can we predict those with OA who worsen following a chronic disease management  program?"

Arthritis Care & Research. Accepted: Jan 05, 2016 DOI 10.1002/acr.2283