This Article  • Full text  • PDF  • eTable  • Reply to article  • Send to a friend  • Save in My Folder  • Save to citation manager  • Permissions  Citing Articles  • Citation map  • Citing articles on HighWire  • Citing articles on Web of Science (1)  • Contact me when this article is cited  Related Content  • Similar articles in this journal  Topic Collections  • Aging/ Geriatrics  • Choroidal Neovascularization  • Macular Degeneration  • Retinal/ Chorioretinal Disorders  • Ophthalmological Disorders, Other  • Ophthalmological Procedures, Other  • Statistics and Research Methods  • Prognosis/ Outcomes  • Alert me on articles by topic  Social Bookmarking   What's this?

Barbara S. Hawkins, PhD; Neil M. Bressler, MD; Sandra M. Reynolds, MA

Arch Ophthalmol. 2009;127(6):725-731.

Objective  To compare 2-year visual acuity outcomes between similar participants assigned to sham and no-treatment control arms in randomized clinical trials.

Methods  We retrospectively matched sham controls from 2 randomized trials to no-treatment controls (no sham or placebo) from 3 trials on 8 baseline prognostic criteria (full matches) or on 4 to 7 criteria (partial matches). Outcomes were compared using data from those who had 2-year visual acuity measurements and also using the last observation carried forward method to impute missing 2-year measurements.

Results  A full match to a no-treatment control was identified for 72 of 321 sham controls (22%); a partial match was identified for another 93 sham controls (29%). Among the fully matched pairs, no important difference in 2-year visual acuity outcomes was observed. However, 2-year outcomes differed somewhat between sham and no-treatment controls within the partially matched pairs.

Conclusions  Findings from fully matched pairs suggest that sham treatment to mask participants in clinical trials may be unnecessary when visual acuity is the outcome of interest. However, findings from the partially matched pairs do not fully support this conclusion. This analysis challenges the necessity for sham (placebo) controls in randomized clinical trials in ophthalmology when visual acuity is the primary outcome of interest.

Author Affiliations: Wilmer Eye Institute, School of Medicine (Drs Hawkins and Bressler) and Department of Epidemiology, Bloomberg School of Public Health (Dr Hawkins and Ms Reynolds), Johns Hopkins University, Baltimore, Maryland.

CiteULike    Connotea    Del.icio.us    Digg    Reddit    Technorati    Twitter     What's this?

THIS ARTICLE HAS BEEN CITED BY OTHER ARTICLES

To Mask or Not to Mask
Beck
Arch Ophthalmol 2009;127:801-802.
FULL TEXT