Background/Purpose: The population is rapidly aging, and by 2060, more than 12 million women will be ages 85 years and older in the United States. As millions of women with total knee (TKR) and total hip (THR) replacements for osteoarthritis (OA) reach old age, it is important to understand which modifiable factors predict disability-free survival after surgery. Although indicators of adiposity, such as high body mass index (BMI), waist circumference (WC), and waist-hip ratio (WHR) are associated with increased risk of OA and utilization of total joint replacement (TJR), their associations with late-life mobility after TJR are unknown. The purpose of this study was to examine associations of BMI, WC, and WHR with mobility limitation at age 85 among women with TKR or THR for OA.

Methods: This was a prospective study of women (aged 65-79 years at baseline) from the Women’s Health Initiative (WHI) recruited during 1993-1998 and followed through 2012. WHI data were linked to Medicare claims data to determine TKR (n=1,867) and THR (n=944) for OA. Women were followed for up to 18 years after undergoing TJR to determine mobility status at age 85. Women who reported that their health limited their ability to walk one block or climb one flight of stairs were classified as having mobility limitation. BMI was defined as normal-weight (≤24.9 kg/m²), overweight (25-29.9), obese I (30-34.9), or obese II (≥35.0). WC and WHR were defined according to cutpoints for abdominal obesity. Multinomial logistic regression models were used to evaluate associations of adiposity measures with mobility limitation at age 85 and death before age 85 (reference category=mobility intact at age 85).

Results: Among women with THR, 45.7% had mobility limitation at age 85, 34.8% had intact mobility at age 85, and 19.6% died before age 85. Among women with TKR, 47.9% had mobility limitation at age 85, 30.4% had intact mobility at age 85, and 21.8% died before age 85. Compared with normal-weight women with THR, overweight (odds ratio [OR]=1.53; 95% confidence interval [CI]=1.04-2.25), obese I (OR=2.40; 95% CI=1.49-3.85), and obese II (OR=4.37; 95% CI=1.96-9.74) women had increased risk of late-life mobility limitation. Obese II women also had increased risk of death before age 85 (OR=6.08; 95% CI=2.39-15.49). Women with THR and WC >88 cm relative to ≤88 cm had increased risk of mobility limitation (OR=1.65; 95% CI=1.17-2.33). WHR was not associated with survival outcomes among women with THR. Among women with TKR, associations of BMI and WC with survival outcomes varied by age at TKR and were strongest in the youngest age group (67-74 years at TKR; OR for mobility limitation=3.24; 95% CI=1.40-7.50 for obese II vs. normal-weight). In the oldest age group (80-82 years at TKR), obesity was associated with increased risk of mobility limitation at age 85 (OR=1.78; 95% CI=1.03-3.06) and death (OR=3.78; 95% CI=1.23-11.67), and WC >88 cm was associated with risk of mobility limitation (OR=1.61; 95% CI=1.07-2.43) but not death.

Conclusion: Among women with THR or TKR for OA, general and abdominal obesity were associated with increased risk of late-life mobility limitation and death. These findings support maintenance of healthy body weight among women with THR or TKR to lessen mobility loss in late life.

« Back to 2017 ACR/ARHP Annual Meeting

ACR Meeting Abstracts - https://acrabstracts.org/abstract/general-and-abdominal-obesity-as-risk-factors-for-late-life-mobility-limitation-among-women-with-total-knee-or-hip-replacement-for-osteoarthritis/