Mortality risk for operated and nonoperated vertebral fracture patients in the medicare population

Abstract

Vertebral compression fractures (VCFs) are associated with increased mortality risk, but the association between surgical treatment and survivorship is unclear. We evaluated the mortality risk for VCF patients undergoing conservative treatment (nonoperated), kyphoplasty, and vertebroplasty. Survival of VCF patients in the 100% U.S. Medicare data set (2005–2008) was estimated by the Kaplan-Meier method, and the differences in mortality rates at up to 4 years were assessed by Cox regression (adjusted for comorbidities) between operated and nonoperated patients and between kyphoplasty and vertebroplasty patients. An instrumental variables analysis was used to evaluate mortality-rate difference between kyphoplasty and vertebroplasty patients. A total of 858,978 VCF patients were identified, including 119,253 kyphoplasty patients and 63,693 vertebroplasty patients. At up to 4 years of follow-up, patients in the operated cohort had a higher adjusted survival rate of 60.8% compared with 50.0% for patients in the nonoperated cohort (p < .001) and were 37% less likely to die [adjusted hazard ratio (HR) = 0.63, p < .001]. The adjusted survival rates for VCF patients following vertebroplasty or kyphoplasty were 57.3% and 62.8%, respectively (p < .001). The relative risk of mortality for kyphoplasty patients was 23% lower than that for vertebroplasty patients (adjusted HR = 0.77, p < .001). Using physician preference as an instrument, the absolute difference in the adjusted survival rate at 3 years was 7.29% higher in patients receiving kyphoplasty than vertebroplasty (p < .001), compared with a crude absolute rate difference of 5.09%. This study established the mortality risk associated with VCFs diagnosed between 2005 and 2008 with respect to different treatment modalities for elderly patients in the entire Medicare population. © 2011 American Society for Bone and Mineral Research.