A surrogate FRAX model for Nepal

Summary A surrogate FRAX® model for Nepal has been constructed using age- and sex-specific hip fracture rates for Indians living in Singapore and age- and sex-specific mortality rates from Nepal.

Introduction FRAX models are frequently requested for countries with little or no data on the incidence of hip fractures. In such circumstances, the development of a surrogate FRAX model is recommended based on country-specific mortality data but using fracture data from a country, usually within the region, where fracture rates are considered to be representative of the index country.

Objective This report describes the development and characteristics of a surrogate FRAX model for Nepal.

Methods The FRAX model used the ethnic-specific incidence of hip fracture in the Indian community of Singapore, combined with the death risk for Nepal in 2015–2019. The number of hip fractures in 2015 and 2050 was estimated based on the United Nations’ predicted changes in population demography.

Results The surrogate model gave similar hip fracture probabilities to estimates from Sri Lanka, India and Pakistan but lower 10-year fracture probabilities for men and women at older ages compared to the model for Singapore, reflecting a higher mortality risk in Nepal compared with Singapore. There were very close correlations in fracture probabilities between the Nepalese and the Singapore models (r > 0.995) so that the use of the Nepalese model had little impact on the rank order of risk, i.e. a person at the xth percentile of risk with one model will be at the xth percentile of risk with the other. It was estimated that 6897 hip fractures arose in 2015 in individuals aged 50 years and older in Nepal, with a predicted 3-fold increase expected by 2050, when 23,409 hip fractures are expected nationally.

Conclusion The surrogate FRAX model for Nepal provides an opportunity to determine fracture probability within the Nepalese population and help guide decisions about treatment.