Abstract
Background: N-of-1 trials (multiple crossover studies conducted in single individuals) may be ideal for determining individual treatment effects and as a tool to estimate heterogeneity of treatment effects (HTE) in a population. However, comprehensive data on n-of-1 trial methodology and analysis is lacking. We performed this study to describe n-of-1 trial characteristics, examine treatment changes resulting from n-of-1 trial participation, and to determine if trial reporting is adequate for estimating HTE. Methods: We undertook a systematic review of n-of-1 trials published between 1985 and December 2010. Included trials were those having individual treatment episodes as the unit of randomization and reporting individual-specific treatment effects. We abstracted trial characteristics, treatment change information, and analytic Methods. Results: We included 108 trials reporting on 2154 participants. Approximately half (49%) of the trials used a statistical cutoff to determine a superior treatment, whereas the remainder used a graphical comparison (25%) or a clinical significance cutoff (20%). Sixty-seven trials, reporting on 488 people, provided treatment change information: 54% of participants had subsequent treatment decisions consistent with the Results of the trial, 8% had decisions inconsistent with trial Results, and 38% had ambiguous Results. Less than half of the trials (45%) reported adequate information to facilitate the calculation of HTE. Conclusion: N-of-1 trials are a useful tool for enhancing therapeutic precision in a range of conditions and should be conducted more often. To facilitate future meta-analysis, and the estimation of HTE, researchers reporting n-of-1 trial Results should clearly describe individual data.
| Original language | English (US) |
|---|---|
| Pages (from-to) | 761-768 |
| Number of pages | 8 |
| Journal | Medical Care |
| Volume | 49 |
| Issue number | 8 |
| DOIs | |
| State | Published - Aug 2011 |
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Keywords
- clinical trials
- evidence-based medicine
- n-of-1 trials
- systematic review
ASJC Scopus subject areas
- Public Health, Environmental and Occupational Health
Cite this
N-of-1 trials in the medical literature : A systematic review. / Gabler, Nicole B.; Duan, Naihua; Vohra, Sunita; Kravitz, Richard L.
In: Medical Care, Vol. 49, No. 8, 08.2011, p. 761-768.Research output: Contribution to journal › Article
}
TY - JOUR
T1 - N-of-1 trials in the medical literature
T2 - A systematic review
AU - Gabler, Nicole B.
AU - Duan, Naihua
AU - Vohra, Sunita
AU - Kravitz, Richard L
PY - 2011/8
Y1 - 2011/8
N2 - Background: N-of-1 trials (multiple crossover studies conducted in single individuals) may be ideal for determining individual treatment effects and as a tool to estimate heterogeneity of treatment effects (HTE) in a population. However, comprehensive data on n-of-1 trial methodology and analysis is lacking. We performed this study to describe n-of-1 trial characteristics, examine treatment changes resulting from n-of-1 trial participation, and to determine if trial reporting is adequate for estimating HTE. Methods: We undertook a systematic review of n-of-1 trials published between 1985 and December 2010. Included trials were those having individual treatment episodes as the unit of randomization and reporting individual-specific treatment effects. We abstracted trial characteristics, treatment change information, and analytic Methods. Results: We included 108 trials reporting on 2154 participants. Approximately half (49%) of the trials used a statistical cutoff to determine a superior treatment, whereas the remainder used a graphical comparison (25%) or a clinical significance cutoff (20%). Sixty-seven trials, reporting on 488 people, provided treatment change information: 54% of participants had subsequent treatment decisions consistent with the Results of the trial, 8% had decisions inconsistent with trial Results, and 38% had ambiguous Results. Less than half of the trials (45%) reported adequate information to facilitate the calculation of HTE. Conclusion: N-of-1 trials are a useful tool for enhancing therapeutic precision in a range of conditions and should be conducted more often. To facilitate future meta-analysis, and the estimation of HTE, researchers reporting n-of-1 trial Results should clearly describe individual data.
AB - Background: N-of-1 trials (multiple crossover studies conducted in single individuals) may be ideal for determining individual treatment effects and as a tool to estimate heterogeneity of treatment effects (HTE) in a population. However, comprehensive data on n-of-1 trial methodology and analysis is lacking. We performed this study to describe n-of-1 trial characteristics, examine treatment changes resulting from n-of-1 trial participation, and to determine if trial reporting is adequate for estimating HTE. Methods: We undertook a systematic review of n-of-1 trials published between 1985 and December 2010. Included trials were those having individual treatment episodes as the unit of randomization and reporting individual-specific treatment effects. We abstracted trial characteristics, treatment change information, and analytic Methods. Results: We included 108 trials reporting on 2154 participants. Approximately half (49%) of the trials used a statistical cutoff to determine a superior treatment, whereas the remainder used a graphical comparison (25%) or a clinical significance cutoff (20%). Sixty-seven trials, reporting on 488 people, provided treatment change information: 54% of participants had subsequent treatment decisions consistent with the Results of the trial, 8% had decisions inconsistent with trial Results, and 38% had ambiguous Results. Less than half of the trials (45%) reported adequate information to facilitate the calculation of HTE. Conclusion: N-of-1 trials are a useful tool for enhancing therapeutic precision in a range of conditions and should be conducted more often. To facilitate future meta-analysis, and the estimation of HTE, researchers reporting n-of-1 trial Results should clearly describe individual data.
KW - clinical trials
KW - evidence-based medicine
KW - n-of-1 trials
KW - systematic review
UR - http://www.scopus.com/inward/record.url?scp=79961030340&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=79961030340&partnerID=8YFLogxK
U2 - 10.1097/MLR.0b013e318215d90d
DO - 10.1097/MLR.0b013e318215d90d
M3 - Article
C2 - 21478771
AN - SCOPUS:79961030340
VL - 49
SP - 761
EP - 768
JO - Medical Care
JF - Medical Care
SN - 0025-7079
IS - 8
ER -