Associations of discordance in hip bone mineral density with hip osteoarthrosis severity and progression to total hip replacement in middle-aged adults

BACKGROUND: Side-to-side discordance in hip bone mineral density (BMD) is common. We evaluated the associations of discordance in hip BMD with hip osteoarthritis (OA) severity and the risk of progression to total hip replacement (THR) in middle-aged adults. METHODOLOGY: In 568 participants (aged 47-69 years, 40.3% females) from the Busselton Healthy Ageing Study, including 145 who progressed to THR during a median follow-up of 7.9 years, bilateral hip BMD was measured using dual-energy x-ray absorptiometry (DXA), and Kellgren-Lawrence hip OA grading (0-normal to 4-severe OA) was performed on DXA images of both hips at baseline. Associations were examined using general linear and logistic regression models, accounting for sex, baseline age and BMI. RESULTS: greater discordance in total hip BMD was associated with 9.2% higher odds of having high OA grades (3 or 4) and 13.0% higher odds of post-baseline THR. CONCLUSION: Our data show that greater side-to-side discordance in hip BMD is associated with higher hip OA grades and greater risk of progression to total hip replacement, and thus could be of clinical utility in identifying high-risk patients.