Reduced risk of back pain following teriparatide treatment: a meta-analysis

Vertebral fractures are the most common osteoporotic fracture and may result in back pain with functional limitations and diminished quality of life. Teriparatide [rhPTH (1-34)] has been shown to increase bone mass and reduce the risk of vertebral and other osteoporotic fractures. The aim of this study was to evaluate the effects of teriparatide on the risk of back pain in patients with osteoporosis. A systematic review of the literature was performed, and five trials were identified and included in our analyses. All trials were randomized, double-blinded, and parallel with either new vertebral fracture (n=1) or bone mineral density as the primary endpoint (n=4). Four studies were in postmenopausal women with osteoporosis, and one was in men with idiopathic or hypogonadal osteoporosis. Two trials were placebo controlled, two trials were alendronate controlled, and one trial involved teriparatide plus hormone replacement therapy versus hormone replacement therapy alone. Reports of back pain, defined as new or worsened back pain after initiating the study drug, were obtained from adverse event databases, and the risk of back pain was analyzed using a multivariate Cox proportional hazards model. Results were not statistically heterogeneous (P=0.60) across trials, and there were no differences between groups administered teriparatide 20 or 40 mcg/day doses (P=0.64). The rates of back pain, moderate or severe back pain, and severe back pain per 100 patient-years were numerically lower in the teriparatide versus comparator groups in each study. Compared with the pooled comparator, patients in the pooled teriparatide group had reduced risk for any back pain [relative risk, 0.66 (95% CI, 0.55-0.80)], moderate or severe back pain [relative risk, 0.60 (95% CI, 0.48-0.75)] and severe back pain [relative risk, 0.44 (95% CI, 0.28-0.68)]. Separate meta-analyses comparing teriparatide versus placebo or antiresorptive drugs gave similar results. In conclusion, patients randomized to teriparatide had a reduced risk of new or worsening back pain compared to patients randomized to placebo, hormone replacement therapy or alendronate.