title: Mixed-treatment comparison of anabolic (teriparatide and PTH 1-84) therapies in women with severe osteoporosis.
abstract: OBJECTIVE
  The recent development of compounds with anabolic action on bone have increased the range of therapeutic options for the treatment of osteoporosis and the prevention of fractures. Two major PTH analogs, the synthetic full-length 1-84 PTH molecule and the recombinant 1-34 N-terminal fragment (teriparatide), are available for the treatment of osteoporosis in many countries. There have bee no comparative trials on the bone anabolic effects of these compounds.
  
  
  METHODS
  In this study we applied a mixed treatment comparison (MTC) to compare the efficacy of teriparatide versus PTH 1-84 for the prevention of vertebral and non-vertebral fractures in women with severe osteoporosis. With this approach the relative treatment effect of one intervention over another can be obtained in the absence of head-to-head comparison. Among the candidate papers selected for analysis, two randomized controlled trials investigating the effects of teriparatide and PTH 1-84 met the selection criteria and underwent MTC analysis.
  
  
  RESULTS
  Based on a fixed-effect MTC model analysis of data from two RCTs, teriparatide (20 µg/day) showed a 70% and 94% probability of being the best treatment for the prevention of vertebral and non-vertebral fractures, respectively. Together with a lack of statistical significance, this study has additional limitations. Some differences in trial procedures and populations exist; another limitation concerns the impossibility of carrying out a randomized-effect model MTC, due to sample exiguity. Furthermore, in order to consider unknown or unmeasured differences of covariates across trials, a random-effects approach would be preferred in order to assess the presence of heterogeneity across comparisons. In contrast, in our analysis a fixed-effect MTC model only was used.
  
  
  CONCLUSIONS
  Teriparatide is expected to provide a greater efficacy over PTH 1-84 with both vertebral and non-vertebral fracture prevention in postmenopausal women with severe osteoporosis.
authors.affiliation: Operative Unit of Rheumatology, San Pietro Fateebenefratelli Hospital, Rome, Italy.
authors.forename: A
authors.initials: A
authors.lastname: Migliore
authors.forename: S
authors.initials: S
authors.lastname: Broccoli
authors.forename: U
authors.initials: U
authors.lastname: Massafra
authors.forename: E
authors.initials: E
authors.lastname: Bizzi
authors.forename: B
authors.initials: B
authors.lastname: Frediani
mesh_terms: D000368:Aged; D045930:Anabolic Agents / Q000627:therapeutic use; D050071:Bone Density Conservation Agents / Q000627:therapeutic use*; D005260:Female; D050723:Fractures, Bone / Q000517:prevention & control*; D006801:Humans; D008875:Middle Aged; D010024:Osteoporosis / Q000188:drug therapy*; D015663:Osteoporosis, Postmenopausal / Q000188:drug therapy; D010281:Parathyroid Hormone / Q000627:therapeutic use*; D016103:Spinal Fractures / Q000517:prevention & control; D019379:Teriparatide / Q000627:therapeutic use*
chemical_list: D045930:Anabolic Agents; D050071:Bone Density Conservation Agents; D010281:Parathyroid Hormone; D019379:Teriparatide