title: Comparative efficiency research (COMER): meta-analysis of cost-effectiveness studies.
abstract: BACKGROUND
  The aim of this study was to create a new meta-analysis method for cost-effectiveness studies using comparative efficiency research (COMER).
  
  
  METHODS
  We built a new score named total incremental net benefit (TINB), with inverse variance weighting of incremental net benefits (INB). This permits determination of whether an alternative is cost-effective, given a specific threshold (TINB > 0 test). Before validation of the model, the structure of dependence between costs and quality-adjusted life years (QoL) was analysed using copula distributions. The goodness-of-fit of a Spanish prospective observational study (n = 498) was analysed using the Independent, Gaussian, T, Gumbel, Clayton, Frank and Placket copulas. Validation was carried out by simulating a copula distribution with log-normal distribution for costs and gamma distribution for disutilities. Hypothetical cohorts were created by varying the sample size (n: 15-500) and assuming three scenarios (1-cost-effective; 2-non-cost-effective; 3-dominant). The COMER result was compared to the theoretical result according to the incremental cost-effectiveness ratio (ICER) and the INB, assuming a margin of error of 2,000 and 500 monetary units, respectively.
  
  
  RESULTS
  The Frank copula with positive dependence (-0.4279) showed a goodness-of-fit sufficient to represent costs and QoL (p-values 0.524 and 0.808). The theoretical INB was within the 95% confidence interval of the TINB, based on 15 individuals with a probability > 80% for scenarios 1 and 2, and > 90% for scenario 3. The TINB > 0 test with 15 individuals showed p-values of 0.0105 (SD: 0.0411) for scenario 1, 0.613 (SD: 0.265) for scenario 2 and < 0.0001 for scenario 3.
  
  
  CONCLUSIONS
  COMER is a valid tool for combining cost-effectiveness studies and may be of use to health decision makers.
authors.affiliation: Statistical Department, Facultat de Biologia, University of Barcelona, Avda Diagonal 645, 08028 Barcelona, Spain. ccrespo@ub.edu.
authors.forename: Carlos
authors.initials: C
authors.lastname: Crespo
authors.forename: Antonio
authors.initials: A
authors.lastname: Monleon
authors.forename: Walter
authors.initials: W
authors.lastname: Díaz
authors.forename: Martín
authors.initials: M
authors.lastname: Ríos
mesh_terms: D057186:Comparative Effectiveness Research; D003362:Cost-Benefit Analysis / Q000706:statistics & numerical data*; D003627:Data Interpretation, Statistical; D006801:Humans; D015201:Meta-Analysis as Topic; D011446:Prospective Studies; D019057:Quality-Adjusted Life Years