LOS ANGELES – In the 3 years following bariatric surgery, 50%-70% of adults will experience clinically meaningful easing of bodily pain and improved physical function, a collaborative study shows.
Further, 75% of patients with severe knee and hip pain or disability had lessening of symptoms indicative of osteoarthritis, Wendy C. King, Ph.D., of the University of Pittsburgh Graduate School of Public Health, reported at Obesity Week 2015.
Dr. Wendy C. King
The study also sheds new light on several factors associated with easing of the debilitating joint pain and physical limitations that are common among patients undergoing bariatric surgery.
Previous studies have reported lessening of symptoms after surgery but had small sample sizes, short-term follow-up of 1 year or less, or used obsolete surgical procedures, she said.
The investigators followed 2,221 patients participating in the prospective, observational Longitudinal Assessment of Bariatric Surgery-2 (LABS-2) study who underwent weight-loss surgery at any of ten U.S. hospitals. Most (70%) had Roux-en-Y bypass, 25% laparoscopic adjustable gastric banding, and 5% other procedures. Their median age was 47 years, median body mass index 46 kg/m2, and 79% were female. Follow-up assessment with several validated measures was available in 1,724 (72%) of patients at 3 years.
Short Form Health Survey (SF-36) scores at years 1, 2, and 3 of follow-up were 57.6, 53.5, and 48.6 for bodily pain and 76.5, 74.2, and 70.2 for physical function, Dr. King said.
Knee pain scores on the Western Ontario and McMaster Universities Arthritis Index (WOMAC) were 75.1 at 1 year, 71.6 at year 2, and 71.3 at year 3.
In Poisson mixed models, younger age, higher household income, and fewer depressive symptoms before surgery were among the factors independently related to a higher likelihood of easing of pain and improvements in function, she said. In addition, greater weight loss and lessening of depressive symptoms after surgery predicted easing of pain and improved physical function.
Opioid use and mobility deficits after bariatric surgery, however, proved more thorny outcomes to alter, Dr. King acknowledged.
Less than half of the 353 patients who reported opioid pain medication use at baseline discontinued opioids at years 1, 2, and 3 of follow-up (42.2%, 40.2%, 45.7%).
Only younger age and higher household income at baseline predicted discontinuation, she said. When the SF-36 pain score was added to the model to account for perceived pain, only having less presurgical pain and a more significant postsurgical lessening of pain were related to postsurgical cessation of opioid use.
“It’s possible that the improvement in depressive symptoms and improvement in pain and function are bidirectional,” Dr. King said. “So if you have improvement in pain and function, you may have improvement in depressive symptoms. But I think it’s noteworthy that presurgery depressive symptoms predicted lower likelihood of improvement in pain, suggesting that depressive symptoms may contribute to pain perception in this population.”
Mobility deficits, defined as the inability to complete a timed 400-m walk in 7 minutes, were present in 836 patients (44%) at entry, with deficit remission rates holding steady at each year of follow-up (55.6%, 55.8%, 56.5%).
After controlling for factors related to pain and function (age, income, depressive symptoms, weight loss), baseline pain and easing of pain were related to improvement in function. Thus, effective pain management may also improve physical function in this population, Dr. King suggested.
“These findings may help clinicians identify patients likely to require additional intervention to address pain and physical limitations that may otherwise limit or reduce their quality of life and pose significant barriers to their ability to adopt an active lifestyle,” she said at the meeting, presented by the Obesity Society and the American Society for Metabolic and Bariatric Surgery. “There was some decline in the original improvement between year 1 and year 3, so I think it will be really important for us to get the 7-year data out there to see if that trend continues.”