Timing of symptomatic subsequent vertebral compression fracture associated with different demographic factors

Background: Symptomatic subsequent vertebral compression fracture (VCF; SVCF) is a common complication associated with poor outcomes. Accumulating evidence shows that demographic factors and incidences of symptomatic SVCFs differ during different periods after the primary vertebroplasty (VP). Purpose: To investigate the incidence and demographic factors of symptomatic SVCFs after the primary VP in different periods using registry data in the Taiwan National Health Insurance Research Database. Methods: This retrospective cohort study included 28,343 patients aged ≥ 50 years with painful VCF treated with VP from 2002 to 2016. Symptomatic SVCF was defined as SVCF requiring another VP or re-admission. During the 2-year follow-up, 1955 patients received subsequent VP while 1,407 were readmitted. Cox proportional hazard models were used to compare the risks of subsequent VP or readmission. Results: The cumulative incident rate of subsequent VP and re-hospitalization was 0.87 [95% confidence interval (CI), 0.82 ~ 0.92] and 0.62 (95% CI, 0.58 ~ 0.66) per 100 person-months, respectively, within the first 6 months after the primary VP, and it decreased over time. A multiple Cox regression model showed that age, osteopenia or osteoporosis, Charlson comorbidity index (CCI) were significant independent risk factors of subsequent VP or readmission within the first 6 months. Conclusions: This study demonstrated that the incidence of symptomatic SVCF peaked in the first 6 months after the primary VP. Age, osteoporosis or osteopenia, and CCI were determined to be risk factors in the first 6 months, but only osteoporosis or osteopenia and CCI were risk factors thereafter.