BACKGROUND/OBJECTIVES:
Falls jeopardize the health of older adults, making it important to properly identify fall risk factors. Here, we determine if visual field (VF) damage or other factors confer a similar risk to falling when falls are ascertained as a rate over time (falls/year) or over activity (falls/step).
DESIGN:
Prospective, observational cohort study.
SETTING:
Clinic-based recruitment with real-world monitoring of falls and physical activity.
PATIENTS:
Two-hundred thirty subjects with glaucoma or suspected glaucoma.
MEASUREMENTS:
Patients recorded falls using daily calendars with injuries identified via follow-up questionnaire. Annual one-week accelerometer trials were used to estimate steps. VF results from both eyes were merged to determine integrated VF sensitivity, with lower sensitivity indicating greater VF damage. Other potential risk factors for falls (age, gender, race, comorbid illness, and polypharmacy) were determined by questionnaires.
RESULTS:
The cumulative probability of falls was 45.2 and 61.6% at 12 and 24 months, respectively, while the cumulative probability of injurious falls was 23.3 and 40.0% respectively. Greater VF damage was associated with higher rates of fall/steps (IRR=1.40/5 dB decrement in sensitivity; p=0.004), but not with more falls/year (IRR=1.25/5 dB decrement in sensitivity; p=0.07). Several additional variables (older age, female gender, more comorbid disease) were also associated with a higher rate of falls/step (p<0.02 for all), but not with falls/year (p>0.10). Conversely, African-Americans had fewer falls/year as compared to Caucasians (p=0.002) but did not differ with regards to falls/step (p=0.07). Similar results were obtained when injurious falls were analyzed.
CONCLUSIONS:
Risk factors associated with more frequent falls when walking (falls/step) are not properly identified when analyzing falls as a rate over time (falls/year). Given the clinical importance of preventing falls while preserving physical activity, falls assessment integrated with activity measurement is recommended when determining if a risk factor is associated with falls.