The epidemiology of fractures in Denmark in 2011

In the present study, we used national health care databases to estimate fracture incidence rates (IRs) and compared these IRs based on imputed data. We showed that imputation could lead to both over- and underestimation of IRs, and future research should therefore focus on how to improve those imputations. Osteoporosis is a major public health burden through associated (osteoporotic) fractures. In Denmark, the incidence rates (IRs) of hip fracture are widely available. However, there is limited data about other fracture sites. A recent report could only provide imputed IRs, although nationwide data is readily available in electronic healthcare databases. Therefore, our aim was to estimate fracture site-specific IRs for Denmark in 2011 and to compare those to the previously reported imputed data. Data from the Danish National Hospital Discharge Register was used to estimate age- and gender-specific IRs for any fracture as well as for different fracture sites in the Danish population aged 20 years and older in 2011. Hip fracture IRs were stratified to sub-sites, and IRs were determined for all hip fractures which were confirmed by surgery. The total number of incident fractures in 2011 was 80,760 (IR 191, 95 % confidence interval (CI) 190-192 (per 10,000 person-years)), of which 35,398 (43.8 %, IR 171, 95 % CI 169-173) occurred in men and 45,362 (56.2 %, IR 211, 95 % CI 209-213) in women. The majority of the fractures occurred in the population aged 50 years and older (n = 50,470, IR 249, 95 % CI 247-251). The numbers of any hip fracture were lower than the previously imputed estimates, whereas the number of forearm fractures was higher. We showed age- and gender-specific fracture rates for any fracture as well as for different fracture sites. The IRs of most fracture sites increased with age. Estimating the number of fractures for Denmark based on imputation of data from other countries led to both over- and underestimation. Future research should therefore focus on how to improve those imputations as not all countries have nationwide registry data.