title: Methodologic ramifications of paying attention to sex and gender differences in clinical research.
abstract: BACKGROUND
  Methodologic standards for studies on sex and gender differences should be developed to improve reporting of studies and facilitate their inclusion in systematic reviews. The essence of these studies lies within the concept of effect modification.
  
  
  OBJECTIVE
  This article reviews important methodologic issues in the design and reporting of pharmacogenetic studies.
  
  
  RESULTS
  Differences in effect based on sex or gender should preferably be expressed in absolute terms (risk differences) to facilitate clinical decisions on treatment. Information on the distribution of potential effect modifiers or prognostic factors should be available to prevent a biased comparison of differences in effect between genotypes. Other considerations included the possibility of selective nonavailability of biomaterial and the choice of a statistical model to study effect modification.
  
  
  CONCLUSIONS
  To ensure high study quality, additional methodologic issues should be taken into account when designing and reporting studies on sex and gender differences.
authors.affiliation: Department of Epidemiology, University of Maastricht, Maastricht, The Netherlands. mh.prins@epid.unimaas.nl
authors.forename: Martin H
authors.initials: MH
authors.lastname: Prins
authors.forename: Kim M
authors.initials: KM
authors.lastname: Smits
authors.forename: Luc J
authors.initials: LJ
authors.lastname: Smits
mesh_terms: D035843:Biomedical Research / Q000379:methods; D002986:Clinical Trials as Topic / Q000379:methods*; D005260:Female; D006801:Humans; D008297:Male; D010597:Pharmacogenetics; D012107:Research Design; D012737:Sex Factors