The Library
The power of low back pain trials : a systematic review of power, sample size, and reporting of sample size calculations over time, in trials published between 1980 and 2012
Tools
Froud, Robert J., Rajendran, Dévan, Patel, Shilpa, Bright, Philip, Bjørkli, Tom, Eldridge, Sandra, Buchbinder, Rachelle and Underwood, Martin (2017) The power of low back pain trials : a systematic review of power, sample size, and reporting of sample size calculations over time, in trials published between 1980 and 2012. Spine, 42 (11). E680-E686. doi:10.1097/BRS.0000000000001953 ISSN 0362-2436.
|
PDF
WRAP-power-low-back-spine-trials-Froud-2016.pdf - Accepted Version - Requires a PDF viewer. Available under License Creative Commons: Attribution-Noncommercial 4.0. Download (1280Kb) | Preview |
Official URL: http://doi.org/10.1097/BRS.0000000000001953
Abstract
Study Design. A systematic review of non-specific low back pain (LBP) trials published between 1980 and 2012.
Objectives. To explore what proportion of trials have been powered to detect different bands of effect size; whether there is evidence that sample size in LBP trials has increasing; what proportion of trial reports include a sample size calculation; and whether likelihood of reporting sample size calculations has increased.
Summary of Background Data. Clinical trials should have a sample size sufficient to detect a minimally important difference for a given power and type I error rate. An underpowered trial is one within which probability of type II error is too high. Meta-analyses do not mitigate underpowered trials.
Methods. Reviewers independently abstracted data on sample size at point of analysis, whether a sample size calculation was reported, and year of publication. Descriptive analyses were used to explore ability to detect effect sizes, and regression analyses to explore the relationship between sample size, or reporting sample size calculations, and time.
Results. We included 383 trials. One-third were powered to detect a standardised mean difference of 0.5 or more, and 5% were powered to detect 0.3 or more. The average sample size was 153 people, which increased only slightly (~4 people/year) from 1980 to 2000, and declined slightly (~4.5 people/year) from 2005 to 2011 (P < 0.00005). Sample size calculations were reported in 41% of trials. The odds of reporting a sample size calculation (compared to not reporting one) increased until 2005 and then declined (ORyear=1.06, ORyear^2=0.99; P < 0.00005).
Conclusions. Sample sizes in back pain trials and the reporting of sample size calculations may need to be increased. It may be justifiable to power a trial to detect only large effects in the case of novel interventions.
Item Type: | Journal Article | ||||||||||||||||||
---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
Alternative Title: | |||||||||||||||||||
Subjects: | R Medicine > R Medicine (General) R Medicine > RD Surgery |
||||||||||||||||||
Divisions: | Faculty of Science, Engineering and Medicine > Medicine > Warwick Medical School > Clinical Trials Unit Faculty of Science, Engineering and Medicine > Medicine > Warwick Medical School > Health Sciences Faculty of Science, Engineering and Medicine > Medicine > Warwick Medical School |
||||||||||||||||||
Library of Congress Subject Headings (LCSH): | Backache, Systematic reviews (Medical research) | ||||||||||||||||||
Journal or Publication Title: | Spine | ||||||||||||||||||
Publisher: | Lippincott Williams & Wilkins | ||||||||||||||||||
ISSN: | 0362-2436 | ||||||||||||||||||
Official Date: | 1 June 2017 | ||||||||||||||||||
Dates: |
|
||||||||||||||||||
Volume: | 42 | ||||||||||||||||||
Number: | 11 | ||||||||||||||||||
Page Range: | E680-E686 | ||||||||||||||||||
DOI: | 10.1097/BRS.0000000000001953 | ||||||||||||||||||
Status: | Peer Reviewed | ||||||||||||||||||
Publication Status: | Published | ||||||||||||||||||
Access rights to Published version: | Restricted or Subscription Access | ||||||||||||||||||
Date of first compliant deposit: | 4 October 2016 | ||||||||||||||||||
Date of first compliant Open Access: | 23 May 2017 | ||||||||||||||||||
Funder: | Campus Kristiania, University of Warwick, Monash University, St. Bartholomew's Hospital (London, England), National Health and Medical Research Council (Australia) (NHMRC) | ||||||||||||||||||
RIOXX Funder/Project Grant: |
|
||||||||||||||||||
Related URLs: |
Request changes or add full text files to a record
Repository staff actions (login required)
View Item |
Downloads
Downloads per month over past year