Please use this identifier to cite or link to this item:
Title: The impact of missing data on clinical trials: a re-analysis of a placebo controllied trial of hypericum perforatum (St John's Wort) and sertraline in major depressive disorder.
Authors: Grobler, Anneke C.
Matthews, Glenda
Issue Date: 2014
Source: PSYCHOPHARMACOLOGY, 231 (9), p. 1987-1999
Abstract: Rationale and objective Hypericum perforatum (St John's wort) is used to treat depression, but the effectiveness has not been established. Recent guidelines described the analysis of clinical trials with missing data, inspiring the reanalysis of this trial using proper missing data methods. The objective was to determine whether hypericum was superior to placebo in treating major depression. Methods A placebo-controlled, randomized clinical trial was conducted for 8 weeks to determine the effectiveness of hypericum or sertraline in reducing depression, measured using the Hamilton depression scale. We performed sensitivity analyses under different assumptions about the missing data process. Results Three hundred forty participants were randomized, with 28 % lost to follow-up. The missing data mechanism was not missing completely at random. Under missing at random assumptions, some sensitivity analyses found no difference between either treatment armand placebo, while some sensitivity analyses found a significant difference from baseline to week 8 between sertraline and placebo (−1.28, 95 % credible interval [−2.48; −0.08]), but not between hypericum and placebo (0.56, [−0.64;1.76]). The results were similar when the missing data process was assumed to be missing not at random. Conclusions There is no difference between hypericum and placebo, regardless of the assumption about the missing data process. There is a significant difference between sertraline and placebo with some statistical methods used. It is important to conduct an analysis that takes account of missing data using valid statistically principled methods. The assumptions about the missing data process could influence the results.
Notes: Grobler, AC (reprint author), Univ KwaZulu Natal, Nelson R Mandela Sch Med, Ctr AIDS Programme Res South Africa CAPRISA, Private Bag X7, ZA-4013 Durban, South Africa,
Keywords: St John's wort; hypericum perforatum; herbal medicine; antidepressant; sertraline; Hamilton depression scale; Bayesian; multiple imputation; missing at random; missing not at random
Document URI:
ISSN: 0033-3158
e-ISSN: 1432-2072
DOI: 10.1007/s00213-013-3344-x
ISI #: 000334514200010
Rights: © Springer-Verlag Berlin Heidelberg 2013
Category: A1
Type: Journal Contribution
Validations: ecoom 2015
Appears in Collections:Research publications

Files in This Item:
File Description SizeFormat 
  Restricted Access
Published version467.65 kBAdobe PDFView/Open    Request a copy
Show full item record


checked on Sep 3, 2020


checked on May 21, 2022

Page view(s)

checked on May 20, 2022


checked on May 20, 2022

Google ScholarTM



Items in DSpace are protected by copyright, with all rights reserved, unless otherwise indicated.