Aim: To determine a) re-fracture rates and b) predictors of re-fracture following treatment with teriparatide in a cohort of patients at high risk of fracture.
Methods:Retrospective observational study of 106 subjects initiated on teriparatide therapy between 2010 and 2015. Relevant anthropometric, clinical and technical data were documented from chart review. Predictors of fracture post teriparatide therapy were identified by Cox regression analysis.
Results:At commencement of teriparatide therapy, subjects were 72.9±14.9 years of age (mean ± SD) with a median number of prior fractures of 3 (IQR 2-4). BMD T-scores at the FN and LS were -2.4±0.9 and -2.6±1.2, resp. Prior to teriparatide, 89 patients had received bisphosphonates for a median of 5.0 (IQR 2-8) years, while 11 had received denosumab for 1.0 (IQR 0.5-1.5) year. Teriparatide was given for 17.3±2.8 months, after which 95% of subjects were re-commenced on anti-resorptive therapy.
During 11 (mean 4.0±2.0) years of follow-up, n=23 (22%) subjects re-fractured following completion of teriparatide therapy (39% of re-fractures occurred within 2 years). The majority of re-fractures (74%) were non-hip, non-vertebral. The only significant predictor of re-fracture post-teriparatide was a higher dietary calcium intake (HR 1.79, 95%CI 1.18-2.726), while age, gender, prior fractures, baseline BMD, change in BMD, type of pre- or post-teriparatide therapy were non-predictive.
Conclusion: Following sequential anabolic/anti-resorptive therapy, 78% of subjects who previously fractured on anti-resorptive therapy remained fracture-free for up to 11 years. In this high-risk cohort, higher dietary calcium intake was the only significant predictor of re-fracture post-teriparatide.