Attrition from randomized controlled trials of pharmacological weight loss agents: a systematic review and analysis

  1. A. N. Fabricatore1,
  2. T. A. Wadden1,
  3. R. H. Moore1,2,
  4. M. L. Butryn1,3,
  5. E. A. Gravallese1,
  6. N. E. Erondu4,
  7. S. B. Heymsfield4,
  8. A. M. Nguyen5

Article first published online: 6 MAR 2009

DOI: 10.1111/j.1467-789X.2009.00567.x

Issue

Obesity Reviews

Obesity Reviews

Volume 10, Issue 3, pages 333–341, May 2009

Additional Information

How to Cite

Fabricatore, A. N., Wadden, T. A., Moore, R. H., Butryn, M. L., Gravallese, E. A., Erondu, N. E., Heymsfield, S. B. and Nguyen, A. M. (2009), Attrition from randomized controlled trials of pharmacological weight loss agents: a systematic review and analysis. Obesity Reviews, 10: 333–341. doi: 10.1111/j.1467-789X.2009.00567.x

Author Information

  1. 1

    Center for Weight and Eating Disorders, Department of Psychiatry, University of Pennsylvania School of Medicine, Philadelphia, PA, USA;

  2. 2

    Center for Clinical Epidemiology and Biostatistics, University of Pennsylvania School of Medicine, Philadelphia, PA, USA;

  3. 3

    Department of Psychology, Drexel University, Philadelphia, PA, USA;

  4. 4

    Merck Research Laboratories, Rahway, NJ, USA;

  5. 5

    Merck Research Laboratories, North Wales, PA, USA

*AN Fabricatore, 3535 Market Street, Ste. 3108, Philadelphia, PA 19104-3309, USA. E-mail: fabricat@mail.med.upenn.edu

Publication History

  1. Issue published online: 24 APR 2009
  2. Article first published online: 6 MAR 2009
  3. Received 5 August 2008; revised 5 January 2009; accepted 19 January 2009

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Keywords:

  • Attrition;
  • obesity;
  • pharmacotherapy;
  • retention

Summary

Clinical trials of obesity treatments have been limited by substantial dropout. Participant-level variables do not reliably predict attrition, and study-level variables have not yet been examined. We searched MEDLINE and identified 24 large randomized controlled trials of weight loss medications. These trials were comprised of 23 placebo and 32 drug groups. Two authors independently extracted the following for each treatment group: (i) treatment received; (ii) design characteristics (inclusion of a lead-in period, selection of participants with weight-related comorbidities, study location and number of study visits); (iii) sample characteristics (sample size, % female, and mean baseline age and body mass index); and (iv) attrition (total, adverse event [AE]-related and non-AE-related) at 1 year. The primary outcome was total attrition, which was significantly related to treatment (i.e. 34.9%, 28.6%, 28.3% and 35.1% in placebo, orlistat, sibutramine and rimonabant groups, respectively, P < 0.0001). In adjusted multivariable models, total attrition was significantly lower in groups that completed a pre-randomization lead-in period than in those that did not (29.1% vs. 39.9%, P < 0.01). Gender also was significantly related to total attrition; groups with more women had higher dropout (P < 0.01). The pattern was similar for predicting non-AE-related attrition. Findings suggest ways to design studies that maximize retention.

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