Summary: In this prospective study, half of all falls resulted in injury. Pre-frail adults sustained more injuries, while more frail adults had injuries requiring hospitalization or fractures. Pre-frail adults fell more often when in movement compared with frail adults who fell more often when standing and in indoor public spaces.

Purpose: To assess prospectively how fall environment and direction are related to injury among pre-frail and frail adults.

Methods: We included 200 community-dwelling adults with a prior fall (pre-frail, mean age 77 years) and 173 adults with acute hip fracture (frail, mean age 84 years; 77% community-dwelling). Falls were prospectively recorded using standardized protocols in monthly intervals, including date, time, fall direction and environment, and injury. We used logistic regression to assess the odds of injury adjusting for age, body mass index (BMI), and gender.

Results: We recorded 513 falls and 331 fall-related injuries (64.5%) among the 373 participants. While the fall rate was similar between groups, pre-frail adults had more injuries (71% among pre-frail vs. 56% among frail, p = 0.0004) but a lower incidence of major injuries (9% among pre-frail vs. 27% among frail, p = 0.003). Pre-frail adults fell more often while in movement (84% among pre-frail vs. 55% among frail, p < 0.0001), and frail adults fell more often while standing (26% vs. 15% respectively, p = 0.01). The odds of injury among frail adults was increased 3.3-fold when falling sideways (OR = 3.29, 95% CI = 1.68–6.45) and 2.4-fold when falling in an indoor public space (OR = 2.35, 95% CI = 1.00–5.53), and was reduced when falling at home (OR = 0.55, 95% CI = 0.31–0.98). The odds of injury among pre-frail adults was not influenced by environment and was 53% lower when falling backwards (OR = 0.47, 95% CI = 0.26–0.82).

Conclusion: While pre-frail adults sustain more fall-related injuries, frail adults were more likely to sustain major injuries, especially when falling sideways or outside their home.