WEST PALM BEACH, Fla. — A combined lifestyle intervention program was not sufficient in routine primary care for enabling participants with overweight or obesity and early knee osteoarthritis (OA) symptoms to lose a modest amount of weight to reduce risk for OA progression, according to research presented at the World Congress on Osteoarthritis (OARSI) 2026 Annual Meeting.

The only differences seen between an intervention group and a usual care group were modest differences between men in one strength measure, knee symptoms, and one inflammatory marker.

“The combined lifestyle intervention does not result in meaningful weight loss and improvements in pain and function,” Chantal Hulshof, PhD, a postdoctoral researcher at Erasmus University Medical Center in Rotterdam, Netherlands. Once patients begin to develop early symptoms of knee OA, there’s a narrow window of opportunity to intervene to reduce progression and severity of disease, she said.

Excess weight is a modifiable risk factor for knee OA, with research showing that 5%-10% weight loss can lead to improvements in pain, physical function, and quality of life. Although the literature shows combined lifestyle programs to be most effective for weight loss in people with knee OA, most evidence comes from trials conducted in controlled research settings, Hulshof said.

Her team aimed to assess the effectiveness of a combined lifestyle intervention compared to usual care in people with early knee OA symptoms who had overweight or obesity. Their pragmatic randomized controlled trial enrolled 218 participants with a mean age of 60 years who had a BMI of ≥ 25 and had visited their primary care provider within the previous 2 years.

Two thirds of the participants (65.5%) were women, and the participants had an average BMI of 33 and had experienced symptoms for an average of 21 months. They experienced pain rated at an average of 5 on a 0-10 numeric rating scale. A total of 109 people were randomly assigned to usual care and 109 to the intervention.

The combined lifestyle intervention was a 2-year structured program that provided behavioral support and promoted physical activity and healthy nutrition with the goal of losing at least 5% of body weight. During the first year, participants met with a lifestyle coach individually three times and in a group session twice after initial intake. They also participated in two group sessions with a physical therapist and three group sessions with a dietitian.

During the second year, each participant met with the lifestyle coach twice individually, participated in two group sessions with the lifestyle coach, received an introduction to a local sports coach, and attended three group sessions with a dietitian. The participants filled out questionnaires every 3 months and underwent a physical exam and MRI at baseline and at the 2-year follow-up.

The primary outcomes they assessed were loss of at least 5 kg or 5% of weight, pain at rest and during activity on a numeric rating scale, and structural knee OA progression on MRI. Secondary outcomes included patient-reported outcomes, physical performance measures, and inflammatory markers.

The proportion of participants who lost at least 5 kg or 5% of weight was not significantly different between those in the intervention (21%) and those receiving usual care (24%) (odds ratio [OR], 0.9; 95% CI, 0.4-1.7). There were also no significant differences between the groups on pain, which fell by an average 0.3 points during rest and during activity in both groups.

MRI showed that structural knee OA progression was similar in both groups. Bone marrow lesions showed up in the patellofemoral joint in 48% of intervention participants and 40% of usual care participants. They also appeared in the medial tibiofemoral joint in 34% of intervention participants and 36% of usual care participants.

The only MRI finding that was significantly different between the groups was a higher incidence of bone marrow lesion in the lateral tibiofemoral joint in the intervention group (26%) than in the usual care group (13%; OR, 2.6; 95% CI, 1.1-6.2). Incidence of cartilage lesions and osteophytes showed up in these three joints in similar proportions in both groups.

When the researchers stratified their results by sex, they found that men in the intervention group had significantly greater quadriceps strength (mean, 0.5; 95% CI, 0.04-1.0), fewer knee symptoms (mean, 7.7; 95% CI, 0.2-15.1), and higher levels of interleukin-6 (mean, 1.0; 95% CI, 0.3-1.6). There were no significant differences between the groups for women.

Lifestyle Interventions Need Strong Behavioral Components

One critique of the program was that it did not include an exercise component. “I expected that we would do exercises under the guidance of a physical therapist — exercises that would strengthen and improve my knee and generally reduce the discomfort I was feeling — but no attention was paid to it,” one participant said. A lifestyle coach in the program added, “I think the people involved in the LITE study don’t feel fully heard, because it doesn’t necessarily involve exercise.”

Martin Van Der Esch, a professor of interdisciplinary care of chronic joint disorders at Amsterdam University of Applied Sciences in Amsterdam, Netherlands, was not surprised by the findings, noting that lifestyle intervention programs are often not cost effective.

“Lifestyle interventions are very popular right now, but it’s very ambitious, costs a lot of money, and the effects are not very big,” Van Der Esch told Medscape Medical News. “If you want to reduce weight, if you want to activate people, there should be a very strong behavioral intervention.”

He noted that this trial included a dietitian, a physical therapist, and a lifestyle coach, but not a psychologist or similar professional trained in behavior change.

“People are not losing weight by themselves,” he said. They can keep with a program for a few weeks, maybe a few months, and then the behavior doesn’t stick. “You need a strong coach who is trying to change the behavior and mind of people.”

Other aspects of the program likely need to be far more involved to be successful as well, he said. Instead of simply attending group sessions with a dietitian, for example, participants need to be able to go shopping and then cooking with a dietitian so they can learn what to buy that they like and how to prepare it.

The research was funded by ZonMw and ReumaNederland. Hulshof and Van Der Esch both had no disclosures.

Tara Haelle is a science/health journalist based in Dallas.