title: A local influence sensitivity analysis for incomplete longitudinal depression data.
abstract: In the analyses of incomplete longitudinal clinical trial data, there has been a shift, away from simple ad hoc methods that are valid only if the data are missing completely at random (MCAR), to more principled (likelihood-based or Bayesian) ignorable analyses, which are valid under the less restrictive missing at random (MAR) assumption. The availability of the necessary standard statistical software allows for such analyses in practice. Although the possibility of data missing not at random (MNAR) cannot be ruled out, it is argued that analyses valid under MNAR are not well suited for the primary analysis in clinical trials. Therefore, rather than either forgetting about or blindly shifting to an MNAR framework, the optimal place for MNAR analyses is within a sensitivity analysis context. Such analyses can be used, for example, to assess how sensitive results from an ignorable analysis are to possible departures from MAR and how much results are affected by influential observations. In this article, we apply the local influence sensitivity tool (Verbeke et al., 2001) to a longitudinal depression trial, thereby applying it to continuous outcomes from clinical trials.
authors.affiliation: Eli Lilly & Company, Indianapolis, Indiana, USA.
authors.forename: Shuyi
authors.initials: S
authors.lastname: Shen
authors.forename: Caroline
authors.initials: C
authors.lastname: Beunckens
authors.forename: Craig
authors.initials: C
authors.lastname: Mallinckrodt
authors.forename: Geert
authors.initials: G
authors.lastname: Molenberghs
mesh_terms: D000928:Antidepressive Agents / Q000627:therapeutic use; D001499:Bayes Theorem; D002986:Clinical Trials as Topic / Q000379:methods*; D003627:Data Interpretation, Statistical; D003863:Depression / Q000188:drug therapy; D006801:Humans; D016013:Likelihood Functions; D008137:Longitudinal Studies; D015233:Models, Statistical; D010352:Patient Dropouts; D011569:Psychiatric Status Rating Scales; D012107:Research Design
chemical_list: D000928:Antidepressive Agents