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Keywords:

  • teriparatide;
  • fracture;
  • BMD;
  • femoral neck;
  • bone turnover;
  • amino-terminal extension peptide of procollagen type I

Abstract

Response to osteoporosis therapy is often assessed by serial BMD testing. Patients who lose BMD without secondary causes of bone loss may be considered to be “nonresponders” to treatment. We examined vertebral fracture (VF) risk, change in lumbar spine (LS) BMD, and change in amino-terminal extension peptide of procollagen type I (PINP) in postmenopausal women whose femoral neck (FN) BMD decreased, increased, or was unchanged after receiving teriparatide (TPTD) or placebo (PL) in the Fracture Prevention Trial. FN and LS BMD were measured at baseline and 12 mo. VFs were assessed by lateral spine radiographs at baseline and study endpoint. A BMD change from baseline of >4% was considered to be clinically significant. Decreases of >4% FN BMD were less common in women receiving TPTD (10%) versus PL (16%, p < 0.05), yet women on TPTD who lost FN BMD still had significant reductions in VF risk compared with PL (RR = 0.11; 95% CI = 0.03–0.45). VF risk reduction with TPTD compared with PL was similar across categories of FN BMD change from baseline at 12 mo (loss >4%, loss 0–4%, gain 0–4%, or gain >4%; interaction p = 0.40). Irrespective of FN BMD loss or gain, TPTD-treated women had statistically significant increases in LS BMD and PINP compared with PL. In both groups, losses or gains in FN BMD at 12 mo corresponded to losses or gains in BMC rather than changes in bone area. In conclusion, loss of FN BMD at 12 mo in postmenopausal women with osteoporosis treated with TPTD is nevertheless consistent with a good treatment response in terms of VF risk reduction.