Background/Purpose: Falls, a growing problem among older adults, often lead to hospitalizations, surgeries, and death. Knee and hip osteoarthritis (OA) are known risk factors for falls, but whether they together additionally contribute to falls risk is unknown. This study utilizes a cohort of African American and Caucasian men and women with and without OA to examine the influence of body OA burden on risk for future falls. 

Methods: A longitudinal analysis was performed using data from 2 time points of the Johnston County OA Project. The outcome of interest was falls at follow up (~5 years after initial visit), based on the response to the question “In the last 12 months, have you had any falls of any type?” Baseline risk factors included age, sex, race, body mass index, and prior falls, with a focus on symptomatic OA of the hip and knee (Model 1). Symptomatic OA was defined as patient reported symptoms (pain, aching, or stiffness on most days) and radiographic evidence of OA (Kellgren Lawrence grade ≥ 2 or joint replacement secondary to OA in the tibiofemoral or hip joint) in the same joint. Additional potential contributing factors were 6 comorbid conditions, alcohol and medication use (sleep aids, narcotics, vitamin D, and bisphosphonates), and low back symptoms (Model 2). Logistic regression analyses were used to determine associations (adjusted odds ratios [aOR]) between baseline covariates and falls at follow-up in both Models 1 and 2.

Results: Participants (n=1,619) had a mean age of 62 years (SD 9.03); 72% were Caucasian, 35% male, 22% had ≥ 1 fall within 12 months of the baseline time point and 26% had ≥1 fall within 12 months of the follow up visit. Caucasians (aOR 1.37), females, older adults, those who reported a history of lung problems (aOR 1.56) and particularly those who had a fall at baseline (aOR 2.42) had greater odds of a fall at follow-up (Model 1; Table 1). When controlling for baseline characteristics (Model 1), patients who had symptomatic knee or hip OA had increased odds for falling (aOR 1.41 and 1.70, respectively). In Model 2, Caucasians (aOR 1.41), older adults, those who had a previous fall (aOR 2.38), reported a history of depression (aOR 1.02), and symptomatic hip OA (aOR 1.56) had increased odds of falls. However, the association between falls and symptomatic knee OA as well as female sex were no longer significant. The odds of falls increased with an increasing number of knee and/or hip joints with symptomatic OA: the aOR for patients with 1 involved joint was 1.56 (95% CI 1.12, 2.17), for 2 joints was 1.85 (CI 1.28, 2.68), and for 3-4 joints was 1.91 (95% CI 1.01, 3.65).

Conclusion: This study confirms that symptomatic knee and particularly hip OA are important risk factors for falls and reveals that the risk increases with additional symptomatic knee and hip joints. Future interventions aimed at enhancing fall prevention should not ignore the impact of multiple symptomatic OA joints.