Document 0299
 DOCN  M9550299
 TI    Assessing drug compliance using longitudinal marker data, with
       application to AIDS.
 DT    9505
 AU    Kim HM; Lagakos SW; Department of Biostatistics, Harvard School of
       Public Health,; Boston, MA 02115.
 SO    Stat Med. 1994 Oct 15-30;13(19-20):2141-53. Unique Identifier : AIDSLINE
       MED/95149008
 AB    The assessment of non-compliance to a study medication is an important
       issue in the evaluation of clinical trials of self-administered drugs.
       Traditional methods for evaluating the compliance of subjects include
       self-reported questionnaires and pharmacologic assays of drug levels in
       randomly-drawn blood samples, but each of these has important
       limitations. This paper adapts and extends changepoint methods to assess
       compliance from longitudinal data on laboratory markers that are
       affected by the drug. The maximum likelihood estimators for two models
       are developed and examined. The effect of the drug on the marker
       process, as well as the spacing of the observations of the marker
       process relative to the time of non-compliance determine which model
       parameters are estimable. For the situations examined, the method of
       maximum likelihood is found to perform well in most cases. However, when
       non-compliance begins shortly before the last observation of the marker
       process, these (as well as any other) estimators cannot reliably
       distinguish non-compliance from compliance. The methods are illustrated
       with an example from a recent clinical trial of persons infected with
       HIV.
 DE    Acquired Immunodeficiency Syndrome/*DRUG THERAPY/EPIDEMIOLOGY  Antiviral
       Agents/ADMINISTRATION & DOSAGE/THERAPEUTIC USE  *Biological Markers
       Erythrocyte Indices  Human  Likelihood Functions  *Models, Statistical
       *Patient Compliance  Placebos  Self Administration  Support, U.S. Gov't,
       P.H.S.  Zidovudine/THERAPEUTIC USE  JOURNAL ARTICLE

       SOURCE: National Library of Medicine.  NOTICE: This material may be
       protected by Copyright Law (Title 17, U.S.Code).