Current guidelines recommend 5-7.5% weight loss for osteoarthritis (OA) patients with overweight or obesity. However, the impact of weight loss on the long-term progression of OA remains unclear.
To investigate the association between weight loss and total knee replacement (TKR) or total hip replacement (THR) due to OA among older adults with overweight or obesity.
We obtained longitudinal weight data from the 45 and Up Study - a cohort of New South Wales (NSW) residents aged ≥45 years surveyed in 2006-2009 and again in 2010-2011. Participants with body mass index (BMI) ≥25 kg/m2 and no previous history of knee or hip surgery were included. Weight change was categorized into four groups: >7.5% loss; 5-7.5% loss; stable (<5% change) and >5% gain. Individual data were linked to the NSW Admitted Patient Data Collection to identify the incidence of TKR and THR due to OA up to 30-June-2016.
Of 34,285 participants, 3,116 lost >7.5% weight, 3,287 lost 5-7.5%, and 5,772 gained >5% weight. 1,359 (4.3%) underwent TKR and 673 (2.0%) underwent THR over a mean follow-up of 5 years. Compared to those with stable weight, individuals with weight loss >7.5% had reduced risk of TKR (odds ratio 0.74, 95%CI 0.61-0.91) after adjusting for age, sex, BMI and physical activity. Neither 5-7.5% weight loss nor weight gain was associated with TKR. There was no association between weight change and THR.
Weight loss is associated with reduced risk of TKR but not THR. Losing over 7.5% of initial weight is required to achieve significant long-term benefits.