Patients experience improvements in joint specific pain and function after weight-loss surgery

After weight-loss surgery, 57 percent of patients with significant mobility issues before surgery no longer had them and about 70 percent of those with severe knee and hip pain or disability, experienced improvements in joint specific pain and function, according to new study, funded by the National Institutes of Health (NIH), that followed patients for three years.

The findings were presented here at ObesityWeek 2015, the largest international event focused on the basic science, clinical application and prevention and treatment of obesity. The weeklong conference is hosted by the American Society for Metabolic and Bariatric Surgery (ASMBS) and The Obesity Society (TOS).

"Our study found that clinically meaningful improvements in bodily pain, specific joint pain, and both perceived and objectively measured physical function are common following bariatric surgery. In particular, walking is easier, which impacts patients' ability to adopt a more physically active lifestyle. However, some patients continue to have significant pain and disability," said Wendy King, PhD, Associate Professor of Epidemiology at the University of Pittsburgh Graduate School of Public Health. "In addition to weight loss, we identified several factors related to patients' likelihood of improvement."

Researchers analyzed 2,221 patients (79% female) for joint and bodily pain, related medication use and physical function pre- and annually post-surgery. The median body mass index (BMI) was 46 kg/m² and the average age was 47 years. The majority (70%) underwent Roux-en-Y gastric bypass, a quarter (25%) laparoscopic adjustable gastric band, and 5 percent had other procedures.

Other variables analyzed included: age, sex, race, household income, BMI, smoking status, depressive symptoms, comorbid conditions such as diabetes, and percent weight change. All patient data was obtained from the Longitudinal Assessment of Bariatric Surgery (LABS) 2 study, an observational study of bariatric surgery patients from 10 hospitals across the country.

Despite significant improvements in several measures of pain and function for most people, after three years approximately one-in-six patients reported narcotic pain medication use, 26 percent still had a mobility deficit, and there was large variation in several measures of pain, disability and physical function.

Predictors of Improvements in Pain and Function

Younger age, male sex, higher household income, lower BMI, and fewer depressive symptoms before surgery, predicted a higher likelihood of improvement in several pain and function outcomes. Greater weight loss and improvement in depressive symptoms following surgery were also independently associated with improvements in pain and function after surgery.

A history of stroke, cardiovascular disease, diabetes, and venous edema with ulceration post-surgery had a negative impact on outcomes. Greater pain pre-surgery was associated with a higher likelihood of improvement in pain following surgery, but a lower likelihood of improvement in physical function and specifically, mobility.

"Obesity can affect the knees and hips and cause bodily pain because of all the added stress it puts on the joints. As a result, musculoskeletal problems are quite common among bariatric patients," said John M. Morton, MD, MPH, president of the ASMBS and Chief, Bariatric and Minimally Invasive Surgery, Stanford University School of Medicine, who was not involved in the study. "Bariatric surgery can help reduce or reverse that pain and improve function, but the longer one lives with obesity, the less improvement one may have. In certain cases, some damage to the joints may be irreversible."