Secondary fracture risk after hip fracture in older patients: an updated sex-specific systematic review and meta analysis with GRADE and PAF assessment.

Abstract

The incidence and risk factors of secondary hip fractures is unknown. This study aims to evaluate the sex-specific incidence and risk factors of secondary hip fractures in elderly patients after hip fracture. We did a systematic search of PubMed, Web of Science, Cochrane Library, Embase, MEDLINE, CBM, CNKI, VIP, and Wanfang Database from January 1, 2000 to August 1, 2025, for cohort studies that assessed incidence and risk factors among patients with secondary hip fracture. Eligible studies were appraised using the Newcastle-Ottawa Scale. The primary outcomes were incidence rates for secondary hip fracture, reported separately for man and woman. The secondary outcomes were risk factors for secondary hip fractures. Effect sizes included odds ratio (OR) with 95% confidence intervals (CI). Sensitivity analyses and subgroup analyses were performed to explore sources of heterogeneity. We used the population attributable fraction (PAF) and the grading of recommendations, assessment, development and evaluation (GRADE) to assess contribution and evidence quality. 19 eligible studies were included. The pooled incidence of secondary hip fractures among older adults was 10.63% (95% CI, 9.9%-11.4%), higher in females (14.94%; 95% CI, 0.123-0.178) than in males (9.89%; 95% CI, 0.083-0.116). Significant risk factors were reduced gluteus medius/minimus (G.Med/MinM) and gluteus maximus muscle density, reduced bone mineral density at hip, femoral neck, and intertrochanteric regions, osteoporosis, cognitive impairment, and calcium/vitamin D deficiency. Among these, G.Med/MinM density lower (moderate quality evidence, PAF, 6.54%, 95% CI 0.038-0.093), and calcium/vitamin D deficiency (moderate quality evidence, PAF,1.12%, 95% CI 0.007-0.016) were important factors. Roughly one in ten older adults suffers a secondary hip fracture, with substantially higher rates in women. Muscle degeneration and inadequate calcium/vitamin D intake emerged as the most influential and potentially modifiable contributors. Targeted postoperative interventions addressing these factors may reduce recurrent fracture burden in aging populations. CRD420251136318.