Different risk profiles for hip fractures and distal forearm fractures: a prospective study

In a prospective cohort of elderly persons, aged 70 years and over, we examined risk indicators for which data could be easily obtained, to construct risk profiles for hip fractures and distal forearm fractures. Participants lived independently, in apartment houses for the elderly or in homes for the elderly. At baseline, information was obtained in 2578 subjects on age, gender, residence, mobility and the frequency of going outdoors. Mobility was measured using a walking score ranging from 1 (not able to walk independently) to 3 (able to walk independently for a fair distance). During the study period (median duration 3.5 years, maximum 4 years) 106 participants sustained a hip fracture and 60 participants suffered a distal forearm fracture. Women compared with men, adjusted for age, had a higher risk of hip fracture (adjusted relative risk (RR) = 2.4, 95% confidence interval (CI) 1.3-4.3) and distal forearm fracture (RR = 3.7, 95% CI 1.5-9.2). Age, adjusted for gender, was related to hip fractures only: the relative risk of fracture for those in the highest age category (> 85 years) was 9.5 (95% CI 4.3-21.2) compared with those in the lowest age category (70-75 years). Moderately impaired walking ability compared with normal walking ability, adjusted for age and gender, was associated with a higher risk of hip fracture (RR = 1.8, 95% CI 1.2-2.7) but with a lower risk of distal forearm fracture (RR = 0.4, 95% CI 0.2-0.8). The outdoor score, adjusted for age and gender, was associated with distal forearm fractures only: going outdoors less than once a week, compared with three times or more, was associated with a lower risk of fractures (RR = 0.3, 95% CI 0.1-0.9). In those living in homes for the elderly the risk of hip fracture was higher compared with those living independently (RR = 2.4, 95% CI 1.4-4.2), adjusted for age and gender. Risk profiles were constructed using stepwise Cox's proportional-hazards regression. The risk profile predicted probabilities of sustaining a hip fracture in a 4-year period ranging from 0.4% to 25.9%, and of distal forearm fractures ranging from 0.2% to 4.5%, depending on the subject's characteristics as defined by the risk indicators. We conclude that easily obtainable risk indicators can be used in the prediction of fractures and can discriminate among fracture types.