MedicalResearch.com Interview with:
Wendy King, PhD
Associate Professor of Epidemiology
Epidemiology Data Center, Room 105
University of Pittsburgh
Pittsburgh, PA 15213
MedicalResearch.com: What is the background for this study? What are the main findings?
Dr. King: Severe obesity is associated with significant joint pain and impaired physical function, such as difficulty bending, lifting carrying and walking. Excess weight can lead to joint damage and accompanying pain, resulting in activity restriction and walking limitations. Obesity can also contribute to pain and physical limitations through factors such as impaired cardiorespiratory function, systematic inflammation, reduced flexibility, low strength per body mass, and depression. Previous studies have reported significant improvements in mean values of bodily and joint specific pain, physical function, and walking capacity in the first 3-12 months following RYGB or LAGB. However, very few studies have examined the variability in response to surgery or reported on longer-term follow-up of these procedures.
My colleagues and I followed 2,221 patients participating in the Longitudinal Assessment of Bariatric Surgery-2, a large NIH-funded prospective study of adults with severe obesity undergoing weight-loss surgery at one of 10 hospitals across the U.S. Through three years of follow-up, approximately 50 to 70 % of patients who underwent bariatric surgery reported clinically important improvements in bodily pain, physical function and usual walking speed. About three-quarters of the participants with symptoms indicative of osteoarthritis before surgery experienced improvements in knee and hip pain and function. In addition, over half of participants who had a mobility deficit prior to surgery did not post-surgery. Several baseline characteristics such as younger age, male sex, higher household income, lower body mass index, fewer depressive symptoms and no history of diabetes or venous edema with ulcerations, were associated with a higher chance of improvement in pain and physical function following surgery. In addition, pre- to post-surgery reductions in weight and depressive symptoms, and remission of diabetes and venous edema with ulcerations were associated with pre- to post-surgery improvements. Thus, our findings reinforce results from shorter-term studies by addressing the durability or response and expand our understanding of the variability in response, and what factors are related to chance of improvement.
MedicalResearch.com: What should clinicians and patients take away from your report?
Dr. King: This data can help patients and clinicians develop realistic expectations regarding the impact of bariatric surgery on pain and disability. (As noted above…) Older age, lower income, more depressive symptoms and medical comorbidities, such as diabetes, before surgery were among the factors independently associated with a lower likelihood of improvement in pain and mobility post-surgery, while greater weight loss, greater reduction in depressive symptoms, and remission or improvement in several medical comorbidities were associated with greater likelihood of improvement.
MedicalResearch.com: What recommendations do you have for future research as a result of this study?
Dr. King: Between years 1 and 3 post-surgery, rates of improvement in bodily pain and physical function, based on the 36-item short form health survey (SF-36) significantly decreased from 58% to 49% and 77% to 70%, respectively, white rates of improvement in walking time and knee and hip pain and function did not differ during this time frame. Given that we detected deteriorations in some measures of pain and function between years 1 and 3 post-surgery, evaluating longer-term follow-up will be important for elucidating the durability of surgery-induced improvements, and examining how weight regain, which becomes common two or more years following RYGB and LAGB, and other factors may explain deteriorations.
MedicalResearch.com: Is there anything else you would like to add?
Dr. King: This study’s large, geographically diverse sample, inclusion of multiple validated measures of pain and physical function, longitudinal design, make it one of the most informative study of pain and function following Roux-en-Y gastric bypass and laparoscopic adjustable gastric band, to date.
Our study found that clinically meaningful improvements in bodily pain, specific joint pain and physical function are common following bariatric surgery. In particular, walking is easier, which impacts patients’ ability to adopt a more physically active lifestyle. However, as a group, post-surgery, patients continue to have more pain, on average, than the general US population. At year-3 approximately one in three patients took pain medication within the prior week for back pain or leg pain, and were dissatisfied with their level of back or leg pain. In addition a quarter of patients self-reported limitations walking several blocks and exhibited evidence of an objectively-measured mobility deficit, indicating that a sizable portion of post-surgery patients may have walking limitations that hinder ability to follow physical activity recommendations for weight loss maintenance.
This work was funded by the National Institute of Diabetes and Digestive and Kidney Disease.
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Dr. Wendy King (2016). Joint Pain and Physical Function Commonly Improve after Bariatric Surgery MedicalResearch.com