Risk of New Vertebral Fracture in the Year Following a Fracture

TLDR

Vertebral fractures markedly raise lifetime fracture risk, yet the risk of a subsequent vertebral fracture in the immediate year after an initial fracture has not been quantified. The study aimed to determine the incidence of new vertebral fractures within one year following an incident vertebral fracture. Researchers analyzed data from four large, 3‑year osteoporosis trials involving 2,725 postmenopausal women on placebo, with vertebral fracture status recorded at baseline across 373 centers worldwide. In the first year after an incident fracture, 6.6% of women sustained a new vertebral fracture, with those having baseline fractures experiencing a five‑fold higher risk (RR 5.1) and, among those who fractured, a 19.2% incidence in the following year, rising to a nine‑fold risk (RR 9.3) when prevalent fractures were present.

Abstract

ContextVertebral fractures significantly increase lifetime risk of future fractures, but risk of further vertebral fractures in the period immediately following a vertebral fracture has not been evaluated.ObjectiveTo determine the incidence of further vertebral fracture in the year following a vertebral fracture.Design and SettingAnalysis of data from 4 large 3-year osteoporosis treatment trials conducted at 373 study centers in North America, Europe, Australia, and New Zealand from November 1993 to April 1998.SubjectsPostmenopausal women who had been randomized to a placebo group and for whom vertebral fracture status was known at entry (n = 2725).Main Outcome MeasureOccurrence of radiographically identified vertebral fracture during the year following an incident vertebral fracture.ResultsSubjects were a mean age of 74 years and had a mean of 28 years since menopause. The cumulative incidence of new vertebral fractures in the first year was 6.6%. Presence of 1 or more vertebral fractures at baseline increased risk of sustaining a vertebral fracture by 5-fold during the initial year of the study compared with the incidence in subjects without prevalent vertebral fractures at baseline (relative risk [RR], 5.1; 95% confidence interval [CI], 3.1-8.4; P<.001). Among the 381 participants who developed an incident vertebral fracture, the incidence of a new vertebral fracture in the subsequent year was 19.2% (95% CI, 13.6%-24.8%). This risk was also increased in the presence of prevalent vertebral fractures (RR, 9.3; 95% CI, 1.2-71.6; P = .03).ConclusionOur data indicate that women who develop a vertebral fracture are at substantial risk for additional fracture within the next year.