Effectiveness of non-benzodiazepine hypnotics in treatment of adult insomnia: meta-analysis of data submitted to the Food and Drug Administration.
Level 1 - systematic review of randomized trials
Systematic review and meta-analysis of randomized controlled trials
PubMed 23248080 · doi:10.1136/bmj.e8343
What was done
Systematic review and meta-analysis of FDA regulatory trial datasets for currently approved non-benzodiazepine hypnotics (eszopiclone, zaleplon, and zolpidem) in adults with insomnia. Investigators evaluated randomized, double-blind, parallel, placebo-controlled trials. Outcomes included change scores from baseline to post-test for primary endpoints (polysomnographic and subjective sleep latency) analyzed via random-effects weighted raw and standardized mean differences, secondary sleep outcomes, and weighted least squares meta-regression for moderator effects.
What was found
Across 13 studies involving 4,378 participants and 65 drug-placebo comparisons, Z drugs showed small, statistically significant reductions compared with placebo in polysomnographic sleep latency (weighted standardized mean difference 95% CI -0.57 to -0.16; weighted mean raw difference of -22 minutes, 95% CI -33 to -11 minutes) and subjective sleep latency (weighted standardized mean difference -0.33, 95% CI -0.62 to -0.04). No significant effects were observed for secondary outcomes, though few studies reported them. Greater latency reductions were linked to earlier publication year, larger doses, longer treatment duration, younger or female populations, and zolpidem.
Why it matters
While Z drugs produce a statistically significant reduction in time to fall asleep compared to placebo, the standalone pharmacological effect is modest, indicating that a substantial portion of perceived clinical improvement stems from the placebo response.
Limits
Analysis was restricted to data submitted to the FDA for drug approvals. There were insufficient studies reporting secondary outcomes (such as total sleep time, awakenings, and sleep efficiency) to draw firm conclusions on overall sleep architecture or quality.
Cited by
- partial Meta-analyses demonstrate that hypnotic sleeping medications show a lack of meaningful clinical benefit above and beyond a placebo.