A New Look at Obesity and Osteoarthritis

Many patients don’t want to believe the 2 are linked

By M. Elaine Husni, MD, MPH

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The statistic is all too familiar: More than two-thirds of the U.S. population is overweight or obese. Despite the inescapable evidence that this is a public health concern, little progress has been made in treating obesity successfully.

Reasons for this lack of progress are many. First, there is no “one size fits all” approach to obesity. Similarly, there is a diversity of points of view on the topic, which makes obesity a highly complex issue for healthcare providers (HCPs) and patients alike. Additionally, behavioral change is tough. How else can we explain why many obese patients are willing to undergo total knee replacement surgery (TKR) for osteoarthritis (OA) rather than modify lifestyle behaviors?

In response to these issues, Cleveland Clinic is working to foster a broader understanding of obesity, particularly as it relates to knee OA. Cleveland Clinic is leading a research team in partnership with the DePuy Synthes Companies to take a “whole-patient care” approach to evaluate and treat knee OA in obese patients considering TKR.

OA and Obesity: Connections and Consequences

The multiple comorbidities related to obesity affect almost every body system. Our research team’s interest is the huge impact of obesity on the musculoskeletal system and associated conditions.

OA is one of the most prevalent comorbidities of obesity, and obesity is now recognized as an important modifiable risk factor for OA (figure) ‒ as well as a factor that can accelerate knee OA. Weight loss has been associated with real improvement in pain and function in hip and knee joints affected by OA.

Figure. Prevalence of arthritis by weight in the National Health Interview Survey of U.S. adults, 2007-2009.

Figure. Prevalence of arthritis by weight in the National Health Interview Survey of U.S. adults, 2007-2009.

Obesity increases the risk of knee OA by a variety of mechanisms. These include increased joint loading and changes in body composition, with detrimental effects stemming from adipose-related inflammation and behavioral factors, including diminished physical activity and subsequent loss of protective muscle strength. Interactions among these various mechanisms can present a challenge to the managing physician.

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Beyond its associations with OA, obesity has been linked with higher rates of surgical complications and early postoperative complications in patients undergoing TKR, as well as with longer hospital stays for these patients.1,2 Moreover, there is a direct linear relationship between body mass index and operative time in TKR.3 The implications of these findings will only increase as the annual number of TKRs performed in the United States rises from already high levels (> 600,000 in 20084) to a projected 3.5 million by 2030.5 TKR revisions now account for 8.2 percent of all Medicare dollars spent, and annual hospital charges for TKR will approach $40.8 billion in 2015.6

‘Whole Patient Care’ Program: Objective and Methods

Our research team’s objective is to develop qualitative insights, uncover new findings and make patient-centric recommendations to Cleveland Clinic’s Whole Patient Care pilot program to improve outcomes for obese patients with OA who undergo joint replacement.

Ours is a qualitative study using concepts of ethnography, the branch of anthropology that involves trying to understand how people actually live their lives. Unlike traditional researchers who ask specific, highly practical questions regarding patient care, anthropological researchers visit patients in their homes or offices to observe and listen in a nondirected way. Our goal is to see people’s behavior on their terms, not ours.

Key themes and concepts were extracted and synthesized using ethnographic research methods. A third-party research company was hired to perform the ethnographic research. Fieldwork was conducted from April to October 2012, and data collection included participant observation, in-depth interviews and informal talks with all HCPs who had contact with these patients, including rheumatologists, endocrinologists, internists, psychologists, orthopaedic surgeons, bariatric surgeons, physical therapists and physician assistants.

 Results: Polarized Perceptions

Data from our study suggest that HCPs and patients are polarized in their views of the relationship between obesity and OA. When it comes to the cause of OA, HCPs recognize a clear link and causality between obesity and OA. Patients, on the other hand, seldom recognize themselves as morbidly obese and do not connect their obesity to medical conditions, including OA. Overcoming these gaps in perception is a time-intensive and costly challenge for most HCPs.

Our research showed that some HCPs believe the cause of obesity is largely metabolic, while others believe it is predominantly behavioral/psychological. Most agree it is a complex combination of the two that requires a multifaceted, multidisciplinary treatment approach.

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Patients see obesity primarily as a lifestyle issue and not as an issue that needs medical treatment. They acknowledge that their weight is “unhelpful” to their joints, but they generally believe their OA is caused by heredity or injury. They view their OA and comorbidities such as high blood pressure, heart disease, diabetes and other ailments as reasons why they are obese, not the other way around. For many, comorbidities are also a barrier to considering bariatric surgery.

Implications and Conclusions

Our findings have led us to identify six priority actions that are needed to better address obesity and improve outcomes for obese patients who undergo TKR at Cleveland Clinic:

  1. Close the educational gap surrounding the contributions of obesity to OA.
  2. Design more individualized approaches to weight loss.
  3. Develop better and earlier interventions for obesity.
  4. Create and implement improved education and tools for HCPs and patients.
  5. Establish a single point of contact to coordinate care of obese patients with OA within Cleveland Clinic.
  6. Implement protocols for more systematic referral to Cleveland Clinic’s Bariatric & Metabolic Institute.

As we work to make these priorities a reality, we recognize that because every patient responds differently, it’s important to take an individualized approach to obesity and to view the condition holistically, to promote treatment of the whole patient. A holistic patient assessment could include a medical profile, a psychological evaluation, and assessments of bariatric readiness, dependency/addiction, education level, support networks (family and friends), nutrition literacy, attitudes toward diet and exercise, and past weight-loss efforts.

OA and other comorbidities may represent opportunities to teach and intervene for obese patients in new ways. We are committed to exploring how best to take advantage of such opportunities and to sharing our insights as broadly as possible.

References

  1. Batsis JA, Naessens JM, Keegan MT, et al. Body mass index and the impact on hospital resource use in patients undergoing total knee arthroplasty. J Arthroplasty. 2010;25(8):1250-1257.
  2. Jackson MP, Sexton SA, Walter WL, Walter WK, Zicat BA. The impact of obesity on the mid-term outcome of cementless total knee replacement. J Bone Joint Surg Br. 2009;91(8):1044-1048.
  3. Liabaud B, Patrick DA Jr, Geller JA. Higher body mass index leads to longer operative time in total knee arthroplasty. J Arthroplasty. 2013;28(4):563-565.
  4. Losina E, Thornhill TS, Rome BN, Wright J, Katz JN. The dramatic increase in total knee replacement utilization rates in the United States cannot be fully explained by growth in population size and the obesity epidemic. J Bone Joint Surg Am. 2012;94(3):201-207.
  5. Kurtz S, Ong K, Lau E, Mowat F, Halpern M. Projections of primary and revision hip and knee arthroplasty in the United States from 2005 to 2030. J Bone Joint Surg Am. 2007;89(4):780-785.

Dr. Husni is Department Vice Chair for the Arthritis and Musculoskeletal Center and Director of Clinical Outcomes Research for the Department of Rheumatic and Immunologic Diseases.