Sex‐ and ethnic‐specific patterns in the incidence of hip fracture among older US Asian and non‐Hispanic White adults

Abstract

Background Asian and Pacific Islander (Asian/PI) adults have lower hip fracture incidence than non‐Hispanic White (NHW) adults, but data regarding Asian/PI subgroups are limited. We compared hip fracture incidence among older US Asian/PI and NHW populations, including ethnic subgroup differences. Methods Using observational data from a California healthcare system, we identified Asian/PI and NHW adults aged ≥50 years (2000–2019) and followed subjects to 2021 for hip fracture determined by principal/primary hospital diagnosis or by secondary hospital diagnosis with hip/femur procedure codes. Age‐adjusted hip fracture incidence was calculated with 95% confidence intervals (CIs). Log‐Poisson regression was used to determine fracture incidence rate ratios (IRRs, [CI]; NHW or Chinese as reference) adjusting for age and year. Results Among 215,359 Asian/PI and 776,839 NHW women, hip fracture incidence was 1.34 (1.28–1.40) and 2.97 (2.94–3.01) per 1000 person‐years, respectively, with IRR 0.45 (0.43–0.47). Among 188,328 Asian/PI and 697,046 NHW men, hip fracture incidence was 0.62 (0.58–0.67) and 1.81 (1.78–1.84) per 1000 person‐years, respectively, with IRR 0.34 (0.32–0.37). For the four largest Asian/PI subgroups, Filipina women (IRR 0.85 [0.75–0.96]) had lower, and Japanese (IRR 1.36 [1.20–1.54]) and South Asian (IRR 1.36 [1.07–1.72]) women had higher hip fracture incidence compared to Chinese women. Hip fracture incidence was only higher among South Asian (IRR 1.61 [1.21–2.14]) compared to Chinese men. Conclusion Hip fracture incidence among US Asian/PI adults was 55% (women) and 66% (men) lower than NHW adults, but incidence varied by Asian/PI subgroup. The heterogeneity among Asian/PI adults highlights the importance of examining fracture risk by ethnic subgroup.

Differences in proximal humerus and wrist fracture incidence among US Asian subgroups

“…Lower fracture incidence was also observed among Asian versus White adult Medicare beneficiaries (IRR 0.52 for humerus fracture, 0.63 for wrist fracture), 3 whereas an earlier KPNC study found non‐significant differences in wrist fracture incidence among 449 South Asian compared to NHW women, both much higher than Chinese women 4 . The current study examines much larger South Asian (>24,000) and Chinese (>91,000) populations and reports data for >106,000 US Filipino adults 1 …”

“…Among 403,687 Asian/PI and 1,473,885 NHW adults aged ≥50 years in January 1, 2000 to December 31, 2019, followed up to December 31, 2021, 1 closed proximal humerus fractures (ICD‐9 812.0, ICD‐10 S42.2xxA) and closed/open distal radius or ulna (wrist) fractures (ICD‐9 813.4–5; ICD‐10 S52.5‐6xxA/B/C) were ascertained from hospital, emergency, urgent care, and surgery/orthopedic encounters, excluding high‐energy trauma (ICD‐9 E800‐48, ICD‐10 V00‐99). A small subset identified only by single (secondary) hospital, emergency, or urgent care/surgery/orthopedic outpatient fracture diagnosis not supported by another encounter diagnosis, surgical procedure, fracture aftercare, splint/casting, or virtual care were excluded (7.2% of humerus and 5.5% of wrist fractures).…”

“…A small subset identified only by single (secondary) hospital, emergency, or urgent care/surgery/orthopedic outpatient fracture diagnosis not supported by another encounter diagnosis, surgical procedure, fracture aftercare, splint/casting, or virtual care were excluded (7.2% of humerus and 5.5% of wrist fractures). Subjects contributed person‐time to each 5‐year age strata until fracture outcome or end of follow‐up, and fracture IRRs adjusted for 5‐year age group and calendar year were estimated using log‐Poisson regression 1 . The study was approved by the KPNC Institutional Review Board with waiver of informed consent.…”

“…We recently reported that US Asian and Pacific Islander (PI) adults have lower hip fracture incidence compared to non‐Hispanic White (NHW) adults 1 . However, heterogeneity exists among major Asian/PI subpopulations, with hip fracture incidence rate ratios (IRRs) ranging 0.32–0.64 compared to NHW adults 1 .…”

“…We recently reported that US Asian and Pacific Islander (PI) adults have lower hip fracture incidence compared to non‐Hispanic White (NHW) adults 1 . However, heterogeneity exists among major Asian/PI subpopulations, with hip fracture incidence rate ratios (IRRs) ranging 0.32–0.64 compared to NHW adults 1 . Whether the same exists for other major osteoporotic fractures is uncertain, as upper extremity fractures are not well studied in US racial and ethnic minority populations 2 .…”