Surge in knee osteoarthritis costs related to increasing obesity rate - research

A predicted surge in the financial burden associated with knee osteoarthritis over the next 20 years can be blamed on rising obesity rates and an ageing population, new research has found.

University of Otago researchers Professor Haxby Abbott and Dr Ross Wilson from the Centre of Musculoskeletal Outcomes Research have investigated the cost and demand for surgery associated with knee osteoarthritis.

Osteoarthritis is a fairly common condition and one of the leading causes of disability in New Zealand. A form of arthritis, it occurs when flexible tissue at the ends of bones wears down. 

The researchers found the healthcare costs linked to knee osteoarthritis is projected to almost double to $370 million by 2038 from $199 million in 2013. The number of knee replacement surgeries over that period is predicted to increase from 5070 to 9040.

Knee replacement surgery, while effective in reducing pain, is expensive and only available to a limited number of patients with advanced osteoarthritis. Low-cost alternatives like exercise therapy can alleviate some symptoms.

Alongside an ageing population, Prof Abbott says the increasing financial burden can be blamed on rising rates of obesity. 

Carrying extra weight places stress on joints, often accelerating osteoarthritis. Exercise needed to lose the weight then becomes more difficult due to the joint pain. Tackling obesity early is therefore the most effective solution.

"Without changes in the provision of effective and cost-effective care throughout the disease course, the annual direct healthcare costs of knee osteoarthritis will increase by 85 percent to $370 million by 2038 and an additional 4000 knee replacement surgeries per year will be required," Prof Abbot said.

But the actual cost of knee osteoarthritis may be far higher if non-health related costs - such as time off work, reduced productivity, and additional informal care - was accounted for. Dr Wilson says these costs may be "substantial". 

Dr Wilson and Prof Abbott.
Dr Wilson and Prof Abbott. Photo credit: Supplied.

The researchers advocate for increased public health measures to reduce obesity rates - expected to skyrocket to close to 50 percent of the adult population by the late 2030s.

Dr Wilson told Newshub greater education on healthy lifestyles was necessary.

"To help people back better choices around healthy eating and exercise therapies for people developing osteoarthritis," he said.

The full research can be found in the New Zealand Medical Journal published on Friday.