A prospective survey of hip fracture incidence and outcome was conducted to evaluate their socioeconomic impact. Over the course of 1 year, 404 hip fractures were recorded in 339 women and 65 men following minor or moderate trauma. The subjects' ages were 82.8 +/- 10.0 years (mean +/- SD): 84.1 +/- 9.2 in female and 76.4 +/- 13.7 in male subjects. The overall annual incidence was 104.4/100,000; the incidence in women was 167.1 versus 35.3 in men, with a crude female-to-male ratio of 4.7. However, when adjusted for age, this ratio was 2.7. When adjusted to the 1985 U.S.A. population, the incidence rates were 68.6 overall, 108.8 female, and 26.3 male, and were, respectively, 119.1, 188.8, and 46.1 when adjusted to the 1992 Swiss population. As compared with 105 age-matched non-hip-fracture fallers studied in the same emergency ward, fracture subjects lived more often in nursing homes and took cardiovascular drugs (p < 0.001). The mean length of stay in the orthopedic ward was 16.3 +/- 12.0 days (median 14; range 2-193 days), for a total of 6566 bed-days representing 19.8% of available bed-days. The mean length of stay in rehabilitation hospitals was 63.6 +/- 52.6 days (median 50; range 2-349 days), for a total of 17,099 bed-days, representing 5.2% of available bed-days. For patients who where independent before fracture, the greater length of stay was associated with advanced age and consumption of cardiovascular drugs. The total cost of hospital stay amounted to approximately $44,000 per patient. Mortality was 3.2% in the orthopedic ward and 10.8% in rehabilitation hospitals, for an overall in-hospital mortality rate of 10.4%. Overall, the 1-year mortality was 23.8% (21.5% for women and 35.4% for men), and it was significantly higher than in the general population (p < 0.001). Prognostic factors for mortality were age, sex, consumption of cardiovascular drugs, and previous living circumstances. One year after fracture, 62.6% of the fracture patients had returned to their previous living circumstances, but 17.9% needed a more care-intensive environment. The likelihood of returning to autonomous living circumstances 1 year after fracture was higher in younger subjects, in females, in those living with a partner, and in those in overall better health before the fracture. This prospective survey highlights the high socioeconomic impact and burden of osteoporotic fractures of the proximal femur.