How to reduce the number of patients needed for randomized trials: A basic introduction Journal Article
| Author: | Vickers, A. |
| Article Title: | How to reduce the number of patients needed for randomized trials: A basic introduction |
| Abstract: | Complementary therapies are often used to treat patients with persisting conditions. In a typical randomized trial, patients are assessed for symptom severity at baseline, randomized to treatment or control and then reassessed after a suitable follow-up period. It can be shown that the number of patients required for such trials can be reduced by the use of two methods: repeat measurement and analysis of co-variance (ANCOVA). An example is given of a trial of acupuncture for back pain. Administering the pain questionnaire twice at baseline and four times at follow-up reduces the number of patients by approximately 20% compared to single questionnaire administration. Use of ANCOVA decreases the number of patients by approximately a further 10%. There are considerable economic and ethical advantages to reducing sample size by a third; however, ANCOVA is statistically complex and expert statistical help is required. © 2002 Elsevier Science Ltd. All rights reserved. |
| Keywords: | controlled study; clinical trial; patient selection; follow up; controlled clinical trial; randomized controlled trial; medical assessment; backache; questionnaire; disease severity; statistical analysis; randomized controlled trials; alternative medicine; acupuncture; symptomatology; pain measurement; analysis of variance; medical ethics; pain assessment; economic aspect; sample size; acupuncture therapy; back pain; analysis of covariance; humans; human; article |
| Journal Title: | Complementary Therapies in Medicine |
| Volume: | 9 |
| Issue: | 4 |
| ISSN: | 0965-2299 |
| Publisher: | Elsevier Inc. |
| Date Published: | 2001-12-01 |
| Start Page: | 234 |
| End Page: | 236 |
| Language: | English |
| DOI: | 10.1054/ctim.2001.0467 |
| PUBMED: | 12184352 |
| PROVIDER: | scopus |
| DOI/URL: | |
| Notes: | Export Date: 21 May 2015 -- Source: Scopus |
