Hip fracture burden and projected incidence among older adults in China to 2035: a GBD 2023 modelling study with exploratory hospital case-mix comparison

Hip fracture is a major source of disability and healthcare use among older adults. Rapid population ageing in China is expected to increase demand for fracture prevention and care. Updated GBD estimates and forecasting models evaluated across clinically relevant time horizons are needed for healthcare planning. Annual GBD 2023 estimates of hip fracture incidence, prevalence, and YLDs among Chinese adults aged ≥ 60 years from 1990 to 2023 were analysed. Crude and internally age-standardized rates and Kitagawa decomposition separated age-specific rate changes from age composition effects. log-linear, GAM, and ARIMA models were assessed using sequential held-out and rolling-origin analyses; an AR(1)-adjusted GAM served as a sensitivity analysis. The selected GAM projected age and sex-specific incidence from 2024 to 2035. Hospital records from 2019 to 2025 provided an exploratory local case-mix comparison during the 2019–2023 overlap. The crude incidence rate increased from 556.87 to 1,088.96 per 100,000 between 1990 and 2023, while incident cases increased from 563,488.53 to 3,226,487.39. The internally age-standardized incidence rate increased by 58.46%, and 33.05% of the crude increase was attributable to age composition. Absolute YLDs increased from 201,150.97 to 595,147.20, while the internally age-standardized YLD rate decreased by 10.74%. ARIMA performed best over short horizons, whereas GAM had the lowest 5-10-year RMSE overall (820.30) and among adults aged ≥ 80 years (1,118.88; MAPE 12.46%) and was selected for projection. By 2035, the highest projected rate was in women aged ≥ 95 years (14,266.00 per 100,000), compared with 7,052.89 in men of the same age. Rates increased most in the oldest groups and declined at ages 60–69 years. The hospital series showed a younger local case-mix than the national GBD distribution. Hip fracture burden among older adults in China increased markedly between 1990 and 2023 through both age-specific rate changes and population ageing. Long horizon evaluation supported GAM for projection to 2035, with future incidence remaining highest among the oldest women and varying across age groups. These findings support targeted prevention and planning of surgical, rehabilitation, and long-term care capacity; the hospital comparison provides complementary local context. Not applicable