Risk factors for contralateral hip fractures following femoral neck fractures in elderly: analysis of the Hungarian nationwide health insurance database

This study aims to investigate the significance of demographic and clinical factors on incidence of second (contralateral) hip fracture in elderly Hungarian population using the nationwide health insurance database in Hungary.The study included a total of 3,783 patients (917 males, 2,866 females) treated for primary monotraumatic femoral neck fractures caused by low-energy trauma in the year 2000. Cox regression and Kaplan-Meier survival analyses, and log-rank test were performed to evaluate the following prognostic factors: age, gender, place of living, type of primary fracture and surgical intervention, hospital providing treatment for primary fracture, and comorbidities.A total of 312 patients (8.2%) suffered second hip fractures. The univariate Cox regression analysis showed a significantly higher risk for second hip fracture in patients having advanced age (p=0.001), female gender (p=0.022), living in capital (p=0.024), and having arthroplasty (p=0.001). Advanced age (p≤0.001) and having arthroplasty (p=0.004) were significant risk factors for second hip fractures according to multivariate analysis. Log-rank test showed significantly longer survival in females (p<0.001) than in males and in patients with arthroplasty (p=0.013) compared with those having osteosynthesis.Identification of high-risk groups for second hip fractures is needed to establish effective prevention strategies. Our study demonstrates that the risk of suffering from second hip fractures is higher in females, elderly population, those living in the capital, and patients having undergone arthroplasty.