Understanding Spontaneous Improvement in Clinical Trials
Author Information
Author(s): Krogsbøll Lasse Theis, Hróbjartsson Asbjørn, Gøtzsche Peter C
Primary Institution: The Nordic Cochrane Centre, Rigshospitalet
Hypothesis
To quantify the contributions of spontaneous improvement, placebo effects, and active interventions to observed changes in clinical conditions.
Conclusion
Both spontaneous improvement and placebo effects significantly contribute to treatment outcomes, varying by clinical condition and intervention type.
Supporting Evidence
- Spontaneous improvement accounted for 24% of the treatment effect.
- Placebo effects contributed 20% to the treatment effect.
- Active interventions showed a significant change from baseline across all conditions.
Takeaway
Sometimes people get better on their own or just because they think they will, even without treatment. This study looked at how much of the improvement is due to the treatment versus these other factors.
Methodology
Systematic review and meta-analysis of randomized trials with three arms: no treatment, placebo, and active intervention.
Potential Biases
Potential bias due to lack of blinding in no-treatment and placebo groups.
Limitations
A quarter of eligible trials did not report necessary data for meta-analysis.
Participant Demographics
Included 2900 patients across various clinical conditions.
Statistical Information
P-Value
-0.24 for no treatment, -0.44 for placebo, -1.01 for active treatment
Confidence Interval
95% confidence interval -0.36 to -0.12 for no treatment, -0.61 to -0.28 for placebo, -1.16 to -0.86 for active treatment
Statistical Significance
p<0.05
Digital Object Identifier (DOI)
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