OR01-1 Proximal Femur Fracture Incidence by Sex among Older US Asian/Pacific Islander Adults and non-Hispanic White Adults
Authors: Chandra Malini , Gordon Nancy , Lee Catherine , Lo Joan 
Published: November 2022

Abstract

Background
The burden of proximal femur (hip) fractures is high in older adults and contributes to substantial mortality. Numerous studies also document racial/ethnic differences in hip fracture incidence, lower among US Asian compared to non-Hispanic White (NH-White) adults. These data have informed base population factors used for fracture risk calculation; for US Asian compared to NH-White populations, ratios of 0.50 and 0.64 have been used for women and men, respectively. In this study, we examined age-adjusted and age-specific incidences of hip fracture in a contemporary population of older US adults and compared findings in Asian and NH-White women and men.

Methods
Among adults age ≥50 years who were members of a large US healthcare system during 2010-2019, we identified Asian/Pacific Islander (Asian/PI) and NH-White adults based on self-reported race/ethnicity data. Incident hip fractures were identified during follow-up from 2010 to 2021 (censoring at hip fracture, death, or membership end) based on (1) initial principal/primary hospital diagnosis of femoral neck or pertrochanteric fracture or (2) secondary hospital diagnosis with hip fracture repair procedure(s). The incidence of hip fracture (per 100,000 person-years) by sex and age and overall age-standardized incidence (using the 2010 US Census) were reported with [95% confidence intervals]. To compare sex-specific fracture rates between Asian/PI and NH-White adults, Poisson models were fitted, adjusting for age (5-year age categories).

Results
Among 203,116 Asian/PI and 645,384 NH-White women, we identified 1,436 and 15,214 hip fractures, and among 174,594 Asian/PI and 573,693 NH-White men, we identified 582 and 7051 hip fractures during follow-up, respectively. The age-adjusted incidence of hip fracture was 136 [129-143] and 297 [292-302] per 100,000 person-years for Asian/PI and NH-White women and 54 [49-58] and 149 [145-153] per 100,000 person-years for Asian/PI and NH-White men, respectively. By 5-year age group, hip fracture incidence increased from 4, 40, to 1113 per 100,000 person-years for Asian/PI women and 7, 29, to 528 per 100,000 person-years for Asian/PI men ages 50-54, 65-69, to 85+ years, respectively. These estimates were lower than that observed in respective NH-White women (range 19, 140, to 2068 per 100,000 person-years) and NH-White men (range 22, 85, and 1381 per 100,000 person-years). The age-adjusted relative risk (risk ratio) of fracture comparing Asian/PI to NH-White women was 0.44 [0.41-0.46] and comparing Asian/PI to NH-White men was 0.35 [0.33-0.39].

Conclusion
Hip fracture incidence in Asian/PI women and men is 56% and 65% lower than that observed in NH-White women and men. These findings indicate that racial/ethnic differences in proximal femur fracture persist in contemporary aggregate populations of older US Asian/PI adults compared to NH-White adults. However, given the known and increasing heterogeneity of the US Asian/PI population, future studies should examine whether these risk ratios vary by Asian/PI ethnic subgroups.
Presentation: Saturday, June 11, 2022 11:30 a.m. - 11:45 a.m.