Display Settings:

Format

Send to:

Choose Destination
We are sorry, but NCBI web applications do not support your browser and may not function properly. More information
    J Clin Psychol. 2007 Apr;63(4):373-7.

    Powerful spin in the conclusion of Wampold et al.'s re-analysis of placebo versus no-treatment trials despite similar results as in original review.

    Source

    Hróbjartsson, The Nordic CochraneCentre, Rigshospitalet, Department 7112, Blegdamsvej 9, DK 2100 Copenhagen Ø, Denmark.ah@cochrane.dk

    Abstract

    B. E. Wampold, T. Minami, S. C. Tierney, T. W. Baskin, and K. S. Bhati (2005) re-analyzed trials included in our systematic review of randomized clinical trials that compared placebo with no treatment (A. Hróbjartsson & P. C. Gøtzsche, 2001). Based on 11 trials, B. E. Wampold et al. concluded that " ... the placebo effect is robust" (p. 850). We (2001) concluded, based on 130 trials, that "we found little evidence in general that placebos have powerful clinical effects" (p. 1599). In this commentary, we examine the reasons for this discrepancy. For trials with continuous outcomes, our analyses (82 trials) and that of B. E. Wampold et al. (5 trials) resulted in pooled standardized mean differences that were small and essentially identical: -0.28 (95% confidence interval = -0.38 to -0.19) versus -0.29 (95% confidence interval = -0.52 to -0.06). There was considerable risk of bias (e.g., reporting bias, sample-size bias). Similarly, for trials with binary outcomes, our analysis (32 trials) and that of B. E. Wampold et al. (6 trials) found no statistically significant pooled effect of placebo interventions and were essentially identical: relative risk 0.95 (95% confidence interval = 0.88-1.02) versus odds ratio 0.99 (95% confidence interval = 0.81-1.23). Thus, B. E. Wampold et al.'s conclusion was not substantiated by their data, and is best characterized as powerful spin. .

    Comment in

    Comment on

    PMID:
    17279532
    [PubMed - indexed for MEDLINE]

      Supplemental Content

      Icon for John Wiley & Sons, Inc.

      Save items

      Recent activity

      Your browsing activity is empty.

      Activity recording is turned off.

      Turn recording back on

      See more...
      Write to the Help Desk