Increase in Disability Prevalence Before Hip Fracture

Abstract

Objectives: To establish the prevalence and correlates of disability during the 2 years before hip fracture.

Design: Data from participants who experienced hip fracture in the Health and Retirement Study (HRS) with hip fracture identified using linked Medicare claims. Each participant was interviewed at varying time points in the 2 years before hip fracture. Disability was defined as self-report of the need for assistance in any activity of daily living (walking across the room, eating, bathing, dressing, using the toilet, transferring). Based on the timing between interview and hip fracture, prevalence of disability was calculated in the cohort as a whole over the 2 years before hip fracture and in subgroups defined according to demographic and clinical characteristics.

Setting: The HRS is a nationally representative longitudinal study (1992-2010).

Participants: HRS participants aged ≥65 with hip fracture (mean age at fracture 84, 77% female).

Results: The adjusted prevalence of disability was 20% (95% confidence interval (CI) = 14-25%) 2 years before hip fracture, with little change until approximately 10 months before fracture, when it started to rise, reaching 44% (95% CI = 33-55%) in the month before hip fracture. The prevalence of disability was highest in the last month before fracture for persons aged 85 and older (53%) and for those with dementia (60%).

Conclusion: Care models for hip fracture need to consider not only the acute medical and surgical needs, but also the high level of need for supportive care and caregiver assistance that chronically disabled individuals require.

Keywords: disability; epidemiology; hip fracture.

Figure 1. Raw Prevalence of Disability During the Two Years Prior to Hip Fracture

Participants with hip fracture were interviewed once approximately every two years. Therefore, these subjects were interviewed once within the two years preceding hip fracture. We used these reports to determine the prevalence of disability at varying time points prior to hip fracture. Depicted are the point prevalence of disability (solid circle) in 4 month intervals with 95% CI's (hash marks). The number of participants interviewed at each time interval prior to hip fracture is noted on the x-axis.

Figure 2. Modeled Prevalence of Any Disability in Activities of Daily Living During the Two Years Prior to Hip Fracture

Predicted prevalence of disability modeled as a spline with a single knot at 10 months prior to the occurrence of hip fracture. Solid line represents the average prevalence; shaded areas indicate the 95% confidence boundary. The P value for the increase in disability prevalence during the months before the knot was 0.55, and the P value for the increase in disability prevalence during the 10 months between the knot and the occurrence of hip fracture was 0.002.

Figure 3. Modeled Prevalence of Difficulty Ambulating, Climbing Stairs, Managing Finances, and Taking Medications During the Two Years Prior to Hip Fracture

Predicted prevalence of functional difficulties modeled as a spline with a single knot at 10 months prior to the occurrence of hip fracture. Panel A: Difficulty walking several blocks. Panel B: Difficulty climbing one flight of stairs. Panel C: Difficulty managing finances. Panel D: Difficulty taking medications.