Assessment of fracture risk and its application to screening for postmenopausal osteoporos

Hip fractures in the elderly: a worldwide projection

Osteoporotic fractures are a significant public health problem, resulting in substantial morbidity and mortality. Previous estimates of the economic burden of osteoporosis, however, have not fully accounted for the costs associated with treatment of nonhip fractures, minority populations, or men. Accordingly, the 1995 total direct medical expenditures for the treatment of osteoporotic fractures were estimated for all persons aged 45 years or older in the United States by age group, sex, race, type of fracture, and site of service (inpatient hospital, nursing home, and outpatient). Osteoporosis attribution probabilities were used to estimate the proportion of health service utilization and expenditures for fractures that resulted from osteoporosis. Health care expenditures attributable to osteoporotic fractures in 1995 were estimated at $13.8 billion, of which $10.3 billion (75.1%) was for the treatment of white women, $2.5 billion (18.4%) for white men, $0.7 billion (5.3%) for nonwhite women, and $0.2 billion (1.3%) for nonwhite men. Although the majority of U.S. health care expenditures for the treatment of osteoporotic fractures were for white women, one-fourth of the total was borne by other population subgroups. By site-of-service, $8.6 billion (62.4%) was spent for inpatient care, $3.9 billion (28.2%) for nursing home care, and $1.3 billion (9.4%) for outpatient services. Importantly, fractures at skeletal sites other than the hip accounted for 36.9% of the total attributed health care expenditures nationally. The contribution of nonhip fractures to the substantial morbidity and expenditures associated with osteoporosis has been underestimated by previous researchers.

Medical Expenditures for the Treatment of Osteoporotic Fractures in the United States in 1995: Report from the National Osteoporosis Foundation

UNLABELLED In a population-based, cross-sectional study, we assessed age- and sex-specific changes in bone structure by QCT. Over life, the cross-sectional area of the vertebrae and proximal femur increased by approximately 15% in both sexes, whereas vBMD at these sites decreased by 39-55% and 34-46%, respectively, with greater decreases in women than in men. INTRODUCTION The changes in bone structure and density with aging that lead to fragility fractures are still unclear. MATERIALS AND METHODS In an age- and sex-stratified population sample of 373 women and 323 men (age, 20-97 years), we assessed bone geometry and volumetric BMD (vBMD) by QCT at the lumbar spine, femoral neck, distal radius, and distal tibia. RESULTS In young adulthood, men had 35-42% larger bone areas than women (p < 0.001), consistent with their larger body size. Bone area increased equally over life in both sexes by approximately 15% (p < 0.001) at central sites and by approximately 16% and slightly more in men at peripheral sites. Decreases in trabecular vBMD began before midlife and continued throughout life (p < 0.001), whereas cortical vBMD decreases began in midlife. Average decreases in trabecular vBMD were greater in women (-55%) than in men (-46%, p < 0.001) at central sites, but were similar (-24% and -26%, respectively) at peripheral sites. With aging, cortical area decreased slightly, and the cortex was displaced outwardly by periosteal and endocortical bone remodeling. Cortical vBMD decreased over life more in women ( approximately 25%) than in men (approximately 18%, p < 0.001), consistent with menopausal-induced increases in bone turnover and bone porosity. CONCLUSIONS Age-related changes in bone are complex. Some are beneficial to bone strength, such as periosteal apposition with outward cortical displacement. Others are deleterious, such as increased subendocortical resorption, increased cortical porosity, and, especially, large decreases in trabecular vBMD that may be the most important cause of increased skeletal fragility in the elderly. Our findings further suggest that the greater age-related decreases in trabecular and cortical vBMD and perhaps also their smaller bone size may explain, in large part, why fragility fractures are more common in elderly women than in elderly men.

Population-based study of age and sex differences in bone volumetric density, size, geometry, and structure at different skeletal sites.

It is recommended that intervention thresholds should be based on absolute fracture risk, but there is a large variation in hip fracture incidence from different regions of the world. The aim of this study was to examine heterogeneity of hip fracture probability in different regions from recent estimates of hip fracture incidence and mortality to adjust intervention thresholds. Ten-year probabilities of hip fracture were computed in men and women at 10-year intervals from the age of 50 years and lifetime risks at the age of 50 years from the hazard functions of hip fracture and death. Lifetime risk at the age of 50 years varied from 1% in women from Turkey to 28.5% in women from Sweden. High lifetime risks in women were associated with high lifetime risks in men (r = 0.83). There also were significant correlations of 10-year risk at any age between men and women. Ten-year probability was standardized to that of men and women from Sweden (set at 1.0). There was a 15-fold range in 10-year probability from 1.24 in Norway to 0.08 in Chile. Countries were categorized by 10-year probabilities comprising very high risk (Norway, Iceland, Sweden, Denmark, and the United States), high risk (China [Taiwan {TW}], Germany, Switzerland, Finland, Greece, Canada, The Netherlands, Hungary, Singapore, Italy, United Kingdom, Kuwait, Australia, and Portugal), medium risk (China [Hong Kong {HK}], France, Japan, Spain, Argentina, and China), and low risk (Turkey, Korea, Venezuela, and Chile). The categorization of hip fracture probabilities can be used to adjust intervention thresholds based on age, sex, and relative risk from a reference population such as Sweden.

V. Marchand

Papers

Epidemiology of fractures